Guide to the Secure Configuration of Red Hat Virtualization 4

with profile DRAFT - DISA STIG for Red Hat Virtualization Host (RHVH)
This *draft* profile contains configuration checks that align to the DISA STIG for Red Hat Virtualization Host (RHVH).

The SCAP Security Guide Project
https://www.open-scap.org/security-policies/scap-security-guide

This guide presents a catalog of security-relevant configuration settings for Red Hat Virtualization 4. It is a rendering of content structured in the eXtensible Configuration Checklist Description Format (XCCDF) in order to support security automation. The SCAP content is is available in the scap-security-guide package which is developed at https://www.open-scap.org/security-policies/scap-security-guide.

Providing system administrators with such guidance informs them how to securely configure systems under their control in a variety of network roles. Policy makers and baseline creators can use this catalog of settings, with its associated references to higher-level security control catalogs, in order to assist them in security baseline creation. This guide is a catalog, not a checklist, and satisfaction of every item is not likely to be possible or sensible in many operational scenarios. However, the XCCDF format enables granular selection and adjustment of settings, and their association with OVAL and OCIL content provides an automated checking capability. Transformations of this document, and its associated automated checking content, are capable of providing baselines that meet a diverse set of policy objectives. Some example XCCDF Profiles, which are selections of items that form checklists and can be used as baselines, are available with this guide. They can be processed, in an automated fashion, with tools that support the Security Content Automation Protocol (SCAP). The DISA STIG, which provides required settings for US Department of Defense systems, is one example of a baseline created from this guidance.

Do not attempt to implement any of the settings in this guide without first testing them in a non-operational environment. The creators of this guidance assume no responsibility whatsoever for its use by other parties, and makes no guarantees, expressed or implied, about its quality, reliability, or any other characteristic.

Profile Information

Profile Title	DRAFT - DISA STIG for Red Hat Virtualization Host (RHVH)
Profile ID	xccdf_org.ssgproject.content_profile_rhvh-stig

CPE Platforms

cpe:/o:redhat:enterprise_linux:8::hypervisor
cpe:/a:redhat:enterprise_virtualization_manager:4

Revision History

Current version: 0.1.76

draft (as of 2024-12-21)

System Settings
Services
System Accounting with auditd
1. Configure auditd Rules for Comprehensive Auditing
2. Configure auditd Data Retention

Checklist

Group Guide to the Secure Configuration of Red Hat Virtualization 4 Group contains 101 groups and 375 rules

Group System Settings Group contains 62 groups and 233 rules

[ref] Contains rules that check correct system settings.

Group Installing and Maintaining Software Group contains 12 groups and 35 rules

[ref] The following sections contain information on security-relevant choices during the initial operating system installation process and the setup of software updates.

Group System and Software Integrity Group contains 7 groups and 21 rules

[ref] System and software integrity can be gained by installing antivirus, increasing system encryption strength with FIPS, verifying installed software, enabling SELinux, installing an Intrusion Prevention System, etc. However, installing or enabling integrity checking tools cannot prevent intrusions, but they can detect that an intrusion may have occurred. Requirements for integrity checking may be highly dependent on the environment in which the system will be used. Snapshot-based approaches such as AIDE may induce considerable overhead in the presence of frequent software updates.

Group Software Integrity Checking Group contains 2 groups and 10 rules

[ref] Both the AIDE (Advanced Intrusion Detection Environment) software and the RPM package management system provide mechanisms for verifying the integrity of installed software. AIDE uses snapshots of file metadata (such as hashes) and compares these to current system files in order to detect changes.

The RPM package management system can conduct integrity checks by comparing information in its metadata database with files installed on the system.

Group Verify Integrity with RPM Group contains 3 rules

[ref] The RPM package management system includes the ability to verify the integrity of installed packages by comparing the installed files with information about the files taken from the package metadata stored in the RPM database. Although an attacker could corrupt the RPM database (analogous to attacking the AIDE database as described above), this check can still reveal modification of important files. To list which files on the system differ from what is expected by the RPM database:

$ rpm -qVa

See the man page for rpm to see a complete explanation of each column.

Rule Verify File Hashes with RPM [ref]

Without cryptographic integrity protections, system executables and files can be altered by unauthorized users without detection. The RPM package management system can check the hashes of installed software packages, including many that are important to system security. To verify that the cryptographic hash of system files and commands matches vendor values, run the following command to list which files on the system have hashes that differ from what is expected by the RPM database:

$ rpm -Va --noconfig | grep '^..5'

If the file was not expected to change, investigate the cause of the change using audit logs or other means. The package can then be reinstalled to restore the file. Run the following command to determine which package owns the file:

$ rpm -qf FILENAME

The package can be reinstalled from a yum repository using the command:

$ sudo yum reinstall PACKAGENAME

Alternatively, the package can be reinstalled from trusted media using the command:

$ sudo rpm -Uvh PACKAGENAME

Warning: This rule can take a long time to perform the check and might consume a considerable amount of resources depending on the number of packages present on the system. It is not a problem in most cases, but especially systems with a large number of installed packages can be affected.

Rationale:

The hashes of important files like system executables should match the information given by the RPM database. Executables with erroneous hashes could be a sign of nefarious activity on the system.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_rpm_verify_hashes

References:

cis-csc	11, 2, 3, 9
cjis	5.10.4.1
cobit5	APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02
cui	3.3.8, 3.4.1
disa	CCI-000366, CCI-001749
hipaa	164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i)
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6
iso27001-2013	A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4
nist	CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3)
nist-csf	PR.DS-6, PR.DS-8, PR.IP-1
pcidss	Req-11.5
os-srg	SRG-OS-000480-GPOS-00227
pcidss4	11.5.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if ! ( { rpm --quiet -q kernel ;} && { rpm --quiet -q rpm-ostree ;} && { rpm --quiet -q bootc ;} ); then

# Find which files have incorrect hash (not in /etc, because of the system related config files) and then get files names
files_with_incorrect_hash="$(rpm -Va --noconfig | grep -E '^..5' | awk '{print $NF}' )"

if [ -n "$files_with_incorrect_hash" ]; then
    # From files names get package names and change newline to space, because rpm writes each package to new line
    packages_to_reinstall="$(rpm -qf $files_with_incorrect_hash | tr '\n' ' ')"

    
    yum reinstall -y $packages_to_reinstall
    
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	high
Disruption:	medium
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_hashes

- name: 'Set fact: Package manager reinstall command'
  set_fact:
    package_manager_reinstall_cmd: yum reinstall -y
  when:
  - not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  - ansible_distribution in [ "Fedora", "RedHat", "CentOS", "OracleLinux" ]
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_hashes

- name: 'Set fact: Package manager reinstall command (zypper)'
  set_fact:
    package_manager_reinstall_cmd: zypper in -f -y
  when:
  - not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  - ansible_distribution == "SLES"
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_hashes

- name: Read files with incorrect hash
  command: rpm -Va --nodeps --nosize --nomtime --nordev --nocaps --nolinkto --nouser
    --nogroup --nomode --noghost --noconfig
  register: files_with_incorrect_hash
  changed_when: false
  failed_when: files_with_incorrect_hash.rc > 1
  check_mode: false
  when:
  - not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  - (package_manager_reinstall_cmd is defined)
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_hashes

- name: Create list of packages
  command: rpm -qf "{{ item }}"
  with_items: '{{ files_with_incorrect_hash.stdout_lines | map(''regex_findall'',
    ''^[.]+[5]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
    | list | unique }}'
  register: list_of_packages
  changed_when: false
  check_mode: false
  when:
  - not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  - files_with_incorrect_hash.stdout_lines is defined
  - (files_with_incorrect_hash.stdout_lines | length > 0)
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_hashes

- name: Reinstall packages of files with incorrect hash
  command: '{{ package_manager_reinstall_cmd }} ''{{ item }}'''
  with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
    | unique }}'
  when:
  - not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  - files_with_incorrect_hash.stdout_lines is defined
  - (package_manager_reinstall_cmd is defined and (files_with_incorrect_hash.stdout_lines
    | length > 0))
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_hashes

Rule Verify and Correct Ownership with RPM [ref]

The RPM package management system can check file ownership permissions of installed software packages, including many that are important to system security. After locating a file with incorrect permissions, which can be found with:

rpm -Va | awk '{ if (substr($0,6,1)=="U" || substr($0,7,1)=="G") print $NF }'

run the following command to determine which package owns it:

$ rpm -qf FILENAME

Next, run the following command to reset its permissions to the correct values:

$ sudo rpm --restore PACKAGENAME

Warning: Profiles may require that specific files be owned by root while the default owner defined by the vendor is different. Such files will be reported as a finding and need to be evaluated according to your policy and deployment environment.

Rationale:

Ownership of binaries and configuration files that is incorrect could allow an unauthorized user to gain privileges that they should not have. The ownership set by the vendor should be maintained. Any deviations from this baseline should be investigated.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_rpm_verify_ownership

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9
cjis	5.10.4.1
cobit5	APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.07, DSS06.02, MEA02.01
cui	3.3.8, 3.4.1
disa	CCI-001494, CCI-001496
isa-62443-2009	4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2
nist	CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3)
nist-csf	PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1
pcidss	Req-11.5
os-srg	SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000278-GPOS-00108
pcidss4	11.5.2

Remediation Shell script ⇲

Complexity:	high
Disruption:	medium
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if ! ( { rpm --quiet -q kernel ;} && { rpm --quiet -q rpm-ostree ;} && { rpm --quiet -q bootc ;} ); then

# Declare array to hold set of RPM packages we need to correct permissions for
declare -A SETPERMS_RPM_DICT

# Create a list of files on the system having permissions different from what
# is expected by the RPM database
readarray -t FILES_WITH_INCORRECT_PERMS < <(rpm -Va --nofiledigest | awk '{ if (substr($0,6,1)=="U" || substr($0,7,1)=="G") print $NF }')

for FILE_PATH in "${FILES_WITH_INCORRECT_PERMS[@]}"
do
        RPM_PACKAGE=$(rpm -qf "$FILE_PATH")
	# Use an associative array to store packages as it's keys, not having to care about duplicates.
	SETPERMS_RPM_DICT["$RPM_PACKAGE"]=1
done

# For each of the RPM packages left in the list -- reset its permissions to the
# correct values
for RPM_PACKAGE in "${!SETPERMS_RPM_DICT[@]}"
do
        rpm --restore "${RPM_PACKAGE}"
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	high
Disruption:	medium
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_ownership

- name: Read list of files with incorrect ownership
  command: rpm -Va --nodeps --nosignature --nofiledigest --nosize --nomtime --nordev
    --nocaps --nolinkto --nomode
  register: files_with_incorrect_ownership
  failed_when: files_with_incorrect_ownership.rc > 1
  changed_when: false
  check_mode: false
  when: not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_ownership

- name: Create list of packages
  command: rpm -qf "{{ item }}"
  with_items: '{{ files_with_incorrect_ownership.stdout_lines | map(''regex_findall'',
    ''^[.]+[U|G]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
    | list | unique }}'
  register: list_of_packages
  changed_when: false
  check_mode: false
  when:
  - not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  - (files_with_incorrect_ownership.stdout_lines | length > 0)
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_ownership

- name: Correct file ownership with RPM
  command: rpm --restore '{{ item }}'
  with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
    | unique }}'
  when:
  - not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  - (files_with_incorrect_ownership.stdout_lines | length > 0)
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_ownership

Rule Verify and Correct File Permissions with RPM [ref]

The RPM package management system can check file access permissions of installed software packages, including many that are important to system security. Verify that the file permissions of system files and commands match vendor values. Check the file permissions with the following command:

$ sudo rpm -Va | awk '{ if (substr($0,2,1)=="M") print $NF }'

Output indicates files that do not match vendor defaults. After locating a file with incorrect permissions, run the following command to determine which package owns it:

$ rpm -qf FILENAME

Next, run the following command to reset its permissions to the correct values:

$ sudo rpm --restore PACKAGENAME

Warning: Profiles may require that specific files have stricter file permissions than defined by the vendor. Such files will be reported as a finding and need to be evaluated according to your policy and deployment environment.

Rationale:

Permissions on system binaries and configuration files that are too generous could allow an unauthorized user to gain privileges that they should not have. The permissions set by the vendor should be maintained. Any deviations from this baseline should be investigated.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_rpm_verify_permissions

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9
cjis	5.10.4.1
cobit5	APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.07, DSS06.02, MEA02.01
cui	3.3.8, 3.4.1
disa	CCI-001493, CCI-001494, CCI-001495, CCI-001496
hipaa	164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i)
isa-62443-2009	4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2
nist	CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), CM-6(a)
nist-csf	PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1
pcidss	Req-11.5
os-srg	SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099, SRG-OS-000278-GPOS-00108
pcidss4	11.5.2

Remediation Shell script ⇲

Complexity:	high
Disruption:	medium
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if ! ( { rpm --quiet -q kernel ;} && { rpm --quiet -q rpm-ostree ;} && { rpm --quiet -q bootc ;} ); then

# Declare array to hold set of RPM packages we need to correct permissions for
declare -A SETPERMS_RPM_DICT

# Create a list of files on the system having permissions different from what
# is expected by the RPM database
readarray -t FILES_WITH_INCORRECT_PERMS < <(rpm -Va --nofiledigest | awk '{ if (substr($0,2,1)=="M") print $NF }')

for FILE_PATH in "${FILES_WITH_INCORRECT_PERMS[@]}"
do
        # NOTE: some files maybe controlled by more then one package
        readarray -t RPM_PACKAGES < <(rpm -qf "${FILE_PATH}")
        for RPM_PACKAGE in "${RPM_PACKAGES[@]}"
        do
                # Use an associative array to store packages as it's keys, not having to care about duplicates.
                SETPERMS_RPM_DICT["$RPM_PACKAGE"]=1
        done
done

# For each of the RPM packages left in the list -- reset its permissions to the
# correct values
for RPM_PACKAGE in "${!SETPERMS_RPM_DICT[@]}"
do
	rpm --restore "${RPM_PACKAGE}"
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	high
Disruption:	medium
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_permissions

- name: Read list of files with incorrect permissions
  command: rpm -Va --nodeps --nosignature --nofiledigest --nosize --nomtime --nordev
    --nocaps --nolinkto --nouser --nogroup
  register: files_with_incorrect_permissions
  failed_when: files_with_incorrect_permissions.rc > 1
  changed_when: false
  check_mode: false
  when: not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_permissions

- name: Create list of packages
  command: rpm -qf "{{ item }}"
  with_items: '{{ files_with_incorrect_permissions.stdout_lines | map(''regex_findall'',
    ''^[.]+[M]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
    | list | unique }}'
  register: list_of_packages
  changed_when: false
  check_mode: false
  when:
  - not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  - (files_with_incorrect_permissions.stdout_lines | length > 0)
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_permissions

- name: Correct file permissions with RPM
  command: rpm --restore '{{ item }}'
  with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
    | unique }}'
  when:
  - not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages )
  - (files_with_incorrect_permissions.stdout_lines | length > 0)
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.3.8
  - NIST-800-171-3.4.1
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(c)
  - NIST-800-53-CM-6(d)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - NIST-800-53-SI-7(6)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - high_complexity
  - high_severity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy
  - rpm_verify_permissions

Group Verify Integrity with AIDE Group contains 7 rules

[ref] AIDE conducts integrity checks by comparing information about files with previously-gathered information. Ideally, the AIDE database is created immediately after initial system configuration, and then again after any software update. AIDE is highly configurable, with further configuration information located in

/usr/share/doc/aide-VERSION

Rule Install AIDE [ref]

The aide package can be installed with the following command:

$ sudo yum install aide

Rationale:

The AIDE package must be installed if it is to be available for integrity checking.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_aide_installed

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9
cjis	5.10.1.3
cobit5	APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06
disa	CCI-002696, CCI-001744
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6
ism	1034, 1288, 1341, 1417
iso27001-2013	A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3
nist	CM-6(a)
nist-csf	DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3
pcidss	Req-11.5
os-srg	SRG-OS-000445-GPOS-00199
anssi	R76, R79
pcidss4	11.5.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "aide" ; then
    yum install -y "aide"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[[packages]]
name = "aide"
version = "*"

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_aide_installed

- name: Ensure aide is installed
  package:
    name: aide
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_aide_installed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable


package --add=aide

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include install_aide

class install_aide {
  package { 'aide':
    ensure => 'installed',
  }
}

Rule Build and Test AIDE Database [ref]

Run the following command to generate a new database:

$ sudo /usr/sbin/aide --init

By default, the database will be written to the file /var/lib/aide/aide.db.new.gz. Storing the database, the configuration file /etc/aide.conf, and the binary /usr/sbin/aide (or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity. The newly-generated database can be installed as follows:

$ sudo cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz

To initiate a manual check, run the following command:

$ sudo /usr/sbin/aide --check

If this check produces any unexpected output, investigate.

Rationale:

For AIDE to be effective, an initial database of "known-good" information about files must be captured and it should be able to be verified against the installed files.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_aide_build_database

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9
cjis	5.10.1.3
cobit5	APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06
disa	CCI-002696, CCI-001744
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6
iso27001-2013	A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3
nist	CM-6(a)
nist-csf	DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3
pcidss	Req-11.5
os-srg	SRG-OS-000445-GPOS-00199
anssi	R76, R79
pcidss4	11.5.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "aide" ; then
    yum install -y "aide"
fi

/usr/sbin/aide --init
/bin/cp -p /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_build_database
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Build and Test AIDE Database - Ensure AIDE Is Installed
  ansible.builtin.package:
    name: '{{ item }}'
    state: present
  with_items:
  - aide
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_build_database
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Build and Test AIDE Database - Build and Test AIDE Database
  ansible.builtin.command: /usr/sbin/aide --init
  changed_when: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_build_database
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Build and Test AIDE Database - Check Whether the Stock AIDE Database Exists
  ansible.builtin.stat:
    path: /var/lib/aide/aide.db.new.gz
  register: aide_database_stat
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_build_database
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Build and Test AIDE Database - Stage AIDE Database
  ansible.builtin.copy:
    src: /var/lib/aide/aide.db.new.gz
    dest: /var/lib/aide/aide.db.gz
    backup: true
    remote_src: true
  when:
  - '"kernel" in ansible_facts.packages'
  - (aide_database_stat.stat.exists is defined and aide_database_stat.stat.exists)
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_build_database
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure Periodic Execution of AIDE [ref]

At a minimum, AIDE should be configured to run a weekly scan. To implement a daily execution of AIDE at 4:05am using cron, add the following line to /etc/crontab:

05 4 * * * root /usr/sbin/aide --check

To implement a weekly execution of AIDE at 4:05am using cron, add the following line to /etc/crontab:

05 4 * * 0 root /usr/sbin/aide --check

AIDE can be executed periodically through other means; this is merely one example. The usage of cron's special time codes, such as @daily and @weekly is acceptable.

Rationale:

By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.

Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security.

Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's Information Management Officer (IMO)/Information System Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_aide_periodic_cron_checking

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9
cjis	5.10.1.3
cobit5	APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06
disa	CCI-002702, CCI-001744, CCI-002699
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6
iso27001-2013	A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3
nist	SI-7, SI-7(1), CM-6(a)
nist-csf	DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3
pcidss	Req-11.5
os-srg	SRG-OS-000363-GPOS-00150, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201
anssi	R76
pcidss4	11.5.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "aide" ; then
    yum install -y "aide"
fi

if ! grep -q "/usr/sbin/aide --check" /etc/crontab ; then
    echo "05 4 * * * root /usr/sbin/aide --check" >> /etc/crontab
else
    sed -i '\!^.* --check.*$!d' /etc/crontab
    echo "05 4 * * * root /usr/sbin/aide --check" >> /etc/crontab
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_periodic_cron_checking
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure AIDE is installed
  package:
    name: '{{ item }}'
    state: present
  with_items:
  - aide
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_periodic_cron_checking
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set cron package name - RedHat
  set_fact:
    cron_pkg_name: cronie
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_os_family == "RedHat" or ansible_os_family == "Suse"
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_periodic_cron_checking
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set cron package name - Debian
  set_fact:
    cron_pkg_name: cron
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_os_family == "Debian"
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_periodic_cron_checking
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Install cron
  package:
    name: '{{ cron_pkg_name }}'
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_periodic_cron_checking
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Periodic Execution of AIDE
  cron:
    name: run AIDE check
    minute: 5
    hour: 4
    weekday: 0
    user: root
    job: /usr/sbin/aide --check
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - PCI-DSS-Req-11.5
  - PCI-DSSv4-11.5.2
  - aide_periodic_cron_checking
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure Notification of Post-AIDE Scan Details [ref]

AIDE should notify appropriate personnel of the details of a scan after the scan has been run. If AIDE has already been configured for periodic execution in /etc/crontab, append the following line to the existing AIDE line:

 | /bin/mail -s "$(hostname) - AIDE Integrity Check" root@localhost

Otherwise, add the following line to /etc/crontab:

05 4 * * * root /usr/sbin/aide --check | /bin/mail -s "$(hostname) - AIDE Integrity Check" root@localhost

AIDE can be executed periodically through other means; this is merely one example.

Rationale:

Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security.

Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's Information Management Officer (IMO)/Information System Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_aide_scan_notification

References:

cis-csc	1, 11, 12, 13, 15, 16, 2, 3, 5, 7, 8, 9
cobit5	BAI01.06, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07
disa	CCI-002702, CCI-001744, CCI-002699
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 6.2, SR 7.6
iso27001-2013	A.12.1.2, A.12.4.1, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1
nist	CM-6(a), CM-3(5)
nist-csf	DE.CM-1, DE.CM-7, PR.IP-1, PR.IP-3
os-srg	SRG-OS-000363-GPOS-00150, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201
anssi	R76

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "aide" ; then
    yum install -y "aide"
fi
var_aide_scan_notification_email='root@localhost'



CRONTAB=/etc/crontab
CRONDIRS='/etc/cron.d /etc/cron.daily /etc/cron.weekly /etc/cron.monthly'

# NOTE: on some platforms, /etc/crontab may not exist
if [ -f /etc/crontab ]; then
	CRONTAB_EXIST=/etc/crontab
fi

if [ -f /var/spool/cron/root ]; then
	VARSPOOL=/var/spool/cron/root
fi

if ! grep -qR '^.*/usr/sbin/aide\s*\-\-check.*|.*\/bin\/mail\s*-s\s*".*"\s*.*@.*$' $CRONTAB_EXIST $VARSPOOL $CRONDIRS; then
	echo "0 5 * * * root /usr/sbin/aide  --check | /bin/mail -s \"\$(hostname) - AIDE Integrity Check\" $var_aide_scan_notification_email" >> $CRONTAB
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-3(5)
  - NIST-800-53-CM-6(a)
  - aide_scan_notification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_aide_scan_notification_email # promote to variable
  set_fact:
    var_aide_scan_notification_email: !!str root@localhost
  tags:
    - always

- name: Ensure AIDE is installed
  package:
    name: '{{ item }}'
    state: present
  with_items:
  - aide
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-3(5)
  - NIST-800-53-CM-6(a)
  - aide_scan_notification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Notification of Post-AIDE Scan Details
  cron:
    name: run AIDE check
    minute: 5
    hour: 4
    weekday: 0
    user: root
    job: /usr/sbin/aide  --check | /bin/mail -s "$(hostname) - AIDE Integrity Check"
      {{ var_aide_scan_notification_email }}
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-3(5)
  - NIST-800-53-CM-6(a)
  - aide_scan_notification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure AIDE to Use FIPS 140-2 for Validating Hashes [ref]

By default, the sha512 option is added to the NORMAL ruleset in AIDE. If using a custom ruleset or the sha512 option is missing, add sha512 to the appropriate ruleset. For example, add sha512 to the following line in /etc/aide.conf:

NORMAL = FIPSR+sha512

AIDE rules can be configured in multiple ways; this is merely one example that is already configured by default.

Warning: System Crypto Modules must be provided by a vendor that undergoes FIPS-140 certifications. FIPS-140 is applicable to all Federal agencies that use cryptographic-based security systems to protect sensitive information in computer and telecommunication systems (including voice systems) as defined in Section 5131 of the Information Technology Management Reform Act of 1996, Public Law 104-106. This standard shall be used in designing and implementing cryptographic modules that Federal departments and agencies operate or are operated for them under contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf To meet this, the system has to have cryptographic software provided by a vendor that has undergone this certification. This means providing documentation, test results, design information, and independent third party review by an accredited lab. While open source software is capable of meeting this, it does not meet FIPS-140 unless the vendor submits to this process.

Rationale:

File integrity tools use cryptographic hashes for verifying file contents and directories have not been altered. These hashes must be FIPS 140-2 approved cryptographic hashes.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_aide_use_fips_hashes

References:

cis-csc	2, 3
cobit5	APO01.06, BAI03.05, BAI06.01, DSS06.02
cui	3.13.11
disa	CCI-000366
isa-62443-2009	4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8
iso27001-2013	A.11.2.4, A.12.2.1, A.12.5.1, A.14.1.2, A.14.1.3, A.14.2.4
nist	SI-7, SI-7(1), CM-6(a)
nist-csf	PR.DS-6, PR.DS-8
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "aide" ; then
    yum install -y "aide"
fi

aide_conf="/etc/aide.conf"
forbidden_hashes=(sha1 rmd160 sha256 whirlpool tiger haval gost crc32)

groups=$(LC_ALL=C grep "^[A-Z][A-Za-z_]*" $aide_conf | cut -f1 -d ' ' | tr -d ' ' | sort -u)

for group in $groups
do
	config=$(grep "^$group\s*=" $aide_conf | cut -f2 -d '=' | tr -d ' ')

	if ! [[ $config = *sha512* ]]
	then
		config=$config"+sha512"
	fi

	for hash in "${forbidden_hashes[@]}"
	do
		config=$(echo $config | sed "s/$hash//")
	done

	config=$(echo $config | sed "s/^\+*//")
	config=$(echo $config | sed "s/\+\++/+/")
	config=$(echo $config | sed "s/\+$//")

	sed -i "s/^$group\s*=.*/$group = $config/g" $aide_conf
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_use_fips_hashes
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Configure AIDE to Use FIPS 140-2 for Validating Hashes - Ensure aide is installed
  ansible.builtin.package:
    name: aide
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_use_fips_hashes
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Configure AIDE to Use FIPS 140-2 for Validating Hashes - Set-fact aide config
    file and forbidden hashes
  ansible.builtin.set_fact:
    aide_conf: /etc/aide.conf
    forbidden_hashes:
    - sha1
    - rmd160
    - sha256
    - whirlpool
    - tiger
    - haval
    - gost
    - crc32
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_use_fips_hashes
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Configure AIDE to Use FIPS 140-2 for Validating Hashes - Remove forbidden
    hashes
  ansible.builtin.replace:
    path: '{{ aide_conf }}'
    regexp: (^\s*[A-Z][A-Za-z_]*\s*=.*?)({{ item }}\+|\+?{{ item }})(.*)
    replace: \1\3
  loop: '{{ forbidden_hashes }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_use_fips_hashes
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Configure AIDE to Use FIPS 140-2 for Validating Hashes - Set sha512
  ansible.builtin.replace:
    path: '{{ aide_conf }}'
    regexp: (^\s*[A-Z][A-Za-z_]*\s*=)((?:(?!\+?sha512).)*)\s*$
    replace: \1\2+sha512
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_use_fips_hashes
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Configure AIDE to Verify Access Control Lists (ACLs) [ref]

By default, the acl option is added to the FIPSR ruleset in AIDE. If using a custom ruleset or the acl option is missing, add acl to the appropriate ruleset. For example, add acl to the following line in /etc/aide.conf:

FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256

AIDE rules can be configured in multiple ways; this is merely one example that is already configured by default. The remediation provided with this rule adds acl to all rule sets available in /etc/aide.conf

Rationale:

ACLs can provide permissions beyond those permitted through the file mode and must be verified by the file integrity tools.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_aide_verify_acls

References:

cis-csc	2, 3
cobit5	APO01.06, BAI03.05, BAI06.01, DSS06.02
disa	CCI-000366
isa-62443-2009	4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8
iso27001-2013	A.11.2.4, A.12.2.1, A.12.5.1, A.14.1.2, A.14.1.3, A.14.2.4
nist	SI-7, SI-7(1), CM-6(a)
nist-csf	PR.DS-6, PR.DS-8
os-srg	SRG-OS-000480-GPOS-00227
anssi	R76

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "aide" ; then
    yum install -y "aide"
fi

aide_conf="/etc/aide.conf"


groups=$(LC_ALL=C grep "^[A-Z][A-Za-z_]*" $aide_conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u)


for group in $groups
do
	config=$(grep "^$group\s*=" $aide_conf | cut -f2 -d '=' | tr -d ' ')

	if ! [[ $config = *acl* ]]
	then
		if [[ -z $config ]]
		then
			config="acl"
		else
			config=$config"+acl"
		fi
	fi
	sed -i "s/^$group\s*=.*/$group = $config/g" $aide_conf
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather list of packages
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_verify_acls
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

- name: Get rules groups
  shell: |
    set -o pipefail
    LC_ALL=C grep "^[A-Z][A-Za-z_]*" /etc/aide.conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u || true
  when:
  - '"kernel" in ansible_facts.packages'
  - '''aide'' in ansible_facts.packages'
  register: find_rules_groups_results
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_verify_acls
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure the acl rule is present when aide is installed.
  replace:
    path: /etc/aide.conf
    regexp: (^\s*{{ item }}\s*=\s*)(?!.*acl)([^\s]*)
    replace: \g<1>\g<2>+acl
  when:
  - '"kernel" in ansible_facts.packages'
  - find_rules_groups_results is not skipped and "'aide' in ansible_facts.packages"
  with_items: '{{ find_rules_groups_results.stdout_lines | map(''trim'') | list }}'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_verify_acls
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure AIDE to Verify Extended Attributes [ref]

By default, the xattrs option is added to the FIPSR ruleset in AIDE. If using a custom ruleset or the xattrs option is missing, add xattrs to the appropriate ruleset. For example, add xattrs to the following line in /etc/aide.conf:

FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256

AIDE rules can be configured in multiple ways; this is merely one example that is already configured by default. The remediation provided with this rule adds xattrs to all rule sets available in /etc/aide.conf

Rationale:

Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_aide_verify_ext_attributes

References:

cis-csc	2, 3
cobit5	APO01.06, BAI03.05, BAI06.01, DSS06.02
disa	CCI-000366
isa-62443-2009	4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8
iso27001-2013	A.11.2.4, A.12.2.1, A.12.5.1, A.14.1.2, A.14.1.3, A.14.2.4
nist	SI-7, SI-7(1), CM-6(a)
nist-csf	PR.DS-6, PR.DS-8
os-srg	SRG-OS-000480-GPOS-00227
anssi	R76

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "aide" ; then
    yum install -y "aide"
fi

aide_conf="/etc/aide.conf"


groups=$(LC_ALL=C grep "^[A-Z][A-Za-z_]*" $aide_conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u)


for group in $groups
do
	config=$(grep "^$group\s*=" $aide_conf | cut -f2 -d '=' | tr -d ' ')

	if ! [[ $config = *xattrs* ]]
	then
		if [[ -z $config ]]
		then
			config="xattrs"
		else
			config=$config"+xattrs"
		fi
	fi
	sed -i "s/^$group\s*=.*/$group = $config/g" $aide_conf
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather list of packages
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_verify_ext_attributes
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

- name: Get rules groups
  shell: |
    set -o pipefail
    LC_ALL=C grep "^[A-Z][A-Za-z_]*" /etc/aide.conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u || true
  when:
  - '"kernel" in ansible_facts.packages'
  - '''aide'' in ansible_facts.packages'
  register: find_rules_groups_results
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_verify_ext_attributes
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure the xattrs rule is present when aide is installed.
  replace:
    path: /etc/aide.conf
    regexp: (^\s*{{ item }}\s*=\s*)(?!.*xattrs)([^\s]*)
    replace: \g<1>\g<2>+xattrs
  when:
  - '"kernel" in ansible_facts.packages'
  - find_rules_groups_results is not skipped and "'aide' in ansible_facts.packages"
  with_items: '{{ find_rules_groups_results.stdout_lines | map(''trim'') | list }}'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-7
  - NIST-800-53-SI-7(1)
  - aide_verify_ext_attributes
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

Group Federal Information Processing Standard (FIPS) Group contains 2 rules

[ref] The Federal Information Processing Standard (FIPS) is a computer security standard which is developed by the U.S. Government and industry working groups to validate the quality of cryptographic modules. The FIPS standard provides four security levels to ensure adequate coverage of different industries, implementation of cryptographic modules, and organizational sizes and requirements.

FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets industry and government requirements. For government systems, this allows Security Levels 1, 2, 3, or 4 for use on Red Hat Virtualization 4.

See http://csrc.nist.gov/publications/PubsFIPS.html for more information.

Rule Enable Dracut FIPS Module [ref]

To enable FIPS mode, run the following command:

fips-mode-setup --enable

To enable FIPS, the system requires that the fips module is added in dracut configuration. Check if /etc/dracut.conf.d/40-fips.conf contain add_dracutmodules+=" fips "

Warning: The system needs to be rebooted for these changes to take effect.

Rationale:

Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_enable_dracut_fips_module

References:

disa	CCI-002450, CCI-000068, CCI-002418, CCI-000877
ism	1446
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1
nist	SC-12(2), SC-12(3), IA-7, SC-13, CM-6(a), SC-12
ospp	FCS_RBG_EXT.1
os-srg	SRG-OS-000478-GPOS-00223

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) && rpm --quiet -q kernel ); then

fips-mode-setup --enable
FIPS_CONF="/etc/dracut.conf.d/40-fips.conf"
if ! grep "^add_dracutmodules+=\" fips \"" $FIPS_CONF; then
    echo "add_dracutmodules+=\" fips \"" >> $FIPS_CONF
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Rule Enable FIPS Mode [ref]

To enable FIPS mode, run the following command:

fips-mode-setup --enable

The fips-mode-setup command will configure the system in FIPS mode by automatically configuring the following:

Setting the kernel FIPS mode flag (/proc/sys/crypto/fips_enabled) to 1
Creating /etc/system-fips
Setting the system crypto policy in /etc/crypto-policies/config to FIPS:OSPP
Loading the Dracut fips module

Warning: The system needs to be rebooted for these changes to take effect.

Warning: This rule DOES NOT CHECK if the components of the operating system are FIPS certified. You can find the list of FIPS certified modules at https://csrc.nist.gov/projects/cryptographic-module-validation-program/validated-modules/search. This rule checks if the system is running in FIPS mode. See the rule description for more information about what it means.

Rationale:

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_enable_fips_mode

References:

disa	CCI-002450, CCI-000068, CCI-002418, CCI-000877
ism	1446
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1
nist	CM-3(6), SC-12(2), SC-12(3), IA-7, SC-13, CM-6(a), SC-12
ospp	FCS_COP.1(1), FCS_COP.1(2), FCS_COP.1(3), FCS_COP.1(4), FCS_CKM.1, FCS_CKM.2, FCS_TLSC_EXT.1, FCS_RBG_EXT.1
os-srg	SRG-OS-000478-GPOS-00223, SRG-OS-000396-GPOS-00176

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) && rpm --quiet -q kernel ); then

var_system_crypto_policy='FIPS:OSPP'


fips-mode-setup --enable

stderr_of_call=$(update-crypto-policies --set ${var_system_crypto_policy} 2>&1 > /dev/null)
rc=$?

if test "$rc" = 127; then
	echo "$stderr_of_call" >&2
	echo "Make sure that the script is installed on the remediated system." >&2
	echo "See output of the 'dnf provides update-crypto-policies' command" >&2
	echo "to see what package to (re)install" >&2

	false  # end with an error code
elif test "$rc" != 0; then
	echo "Error invoking the update-crypto-policies script: $stderr_of_call" >&2
	false  # end with an error code
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations]
fips = true

Remediation Ansible snippet ⇲

Complexity:	medium
Disruption:	medium
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-3(6)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-7
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - enable_fips_mode
  - high_severity
  - medium_complexity
  - medium_disruption
  - reboot_required
  - restrict_strategy
- name: XCCDF Value var_system_crypto_policy # promote to variable
  set_fact:
    var_system_crypto_policy: !!str FIPS:OSPP
  tags:
    - always

- name: Enable FIPS Mode - Check to See the Current Status of FIPS Mode
  ansible.builtin.command: /usr/bin/fips-mode-setup --check
  register: is_fips_enabled
  failed_when: false
  changed_when: false
  when: ( not ( lookup("env", "container") == "bwrap-osbuild" ) and "kernel" in ansible_facts.packages
    )
  tags:
  - NIST-800-53-CM-3(6)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-7
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - enable_fips_mode
  - high_severity
  - medium_complexity
  - medium_disruption
  - reboot_required
  - restrict_strategy

- name: Enable FIPS Mode - Enable FIPS Mode
  ansible.builtin.command: /usr/bin/fips-mode-setup --enable
  when:
  - ( not ( lookup("env", "container") == "bwrap-osbuild" ) and "kernel" in ansible_facts.packages
    )
  - is_fips_enabled.stdout.find('FIPS mode is enabled.') == -1
  tags:
  - NIST-800-53-CM-3(6)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-7
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - enable_fips_mode
  - high_severity
  - medium_complexity
  - medium_disruption
  - reboot_required
  - restrict_strategy

- name: Enable FIPS Mode - Configure Crypto Policy
  ansible.builtin.lineinfile:
    path: /etc/crypto-policies/config
    regexp: ^(?!#)(\S+)$
    line: '{{ var_system_crypto_policy }}'
    create: true
  when: ( not ( lookup("env", "container") == "bwrap-osbuild" ) and "kernel" in ansible_facts.packages
    )
  tags:
  - NIST-800-53-CM-3(6)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-7
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - enable_fips_mode
  - high_severity
  - medium_complexity
  - medium_disruption
  - reboot_required
  - restrict_strategy

- name: Enable FIPS Mode - Verify that Crypto Policy is Set (runtime)
  ansible.builtin.command: /usr/bin/update-crypto-policies --set {{ var_system_crypto_policy
    }}
  when: ( not ( lookup("env", "container") == "bwrap-osbuild" ) and "kernel" in ansible_facts.packages
    )
  tags:
  - NIST-800-53-CM-3(6)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-7
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - enable_fips_mode
  - high_severity
  - medium_complexity
  - medium_disruption
  - reboot_required
  - restrict_strategy

Group System Cryptographic Policies Group contains 6 rules

[ref] Linux has the capability to centrally configure cryptographic polices. The command update-crypto-policies is used to set the policy applicable for the various cryptographic back-ends, such as SSL/TLS libraries. The configured cryptographic policies will be the default policy used by these backends unless the application user configures them otherwise. When the system has been configured to use the centralized cryptographic policies, the administrator is assured that any application that utilizes the supported backends will follow a policy that adheres to the configured profile. Currently the supported backends are:

GnuTLS library
OpenSSL library
NSS library
OpenJDK
Libkrb5
BIND
OpenSSH

Applications and languages which rely on any of these backends will follow the system policies as well. Examples are apache httpd, nginx, php, and others.

Rule Configure BIND to use System Crypto Policy [ref]

Crypto Policies provide a centralized control over crypto algorithms usage of many packages. BIND is supported by crypto policy, but the BIND configuration may be set up to ignore it. To check that Crypto Policies settings are configured correctly, ensure that the /etc/named.conf includes the appropriate configuration: In the options section of /etc/named.conf, make sure that the following line is not commented out or superseded by later includes: include "/etc/crypto-policies/back-ends/bind.config";

Rationale:

Overriding the system crypto policy makes the behavior of the BIND service violate expectations, and makes system configuration more fragmented.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_configure_bind_crypto_policy

References:

disa	CCI-002418, CCI-002422
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1
nist	SC-13, SC-12(2), SC-12(3)
os-srg	SRG-OS-000423-GPOS-00187, SRG-OS-000426-GPOS-00190

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q bind; then

function remediate_bind_crypto_policy() {
	CONFIG_FILE="/etc/named.conf"
	if test -f "$CONFIG_FILE"; then
		sed -i 's|options {|&\n\tinclude "/etc/crypto-policies/back-ends/bind.config";|' "$CONFIG_FILE"
		return 0
	else
		echo "Aborting remediation as '$CONFIG_FILE' was not even found." >&2
		return 1
	fi
}

remediate_bind_crypto_policy

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - configure_bind_crypto_policy
  - configure_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

- name: Configure BIND to use System Crypto Policy - Check BIND configuration file
    exists
  ansible.builtin.stat:
    path: /etc/named.conf
  register: bind_config_file
  when: '"bind" in ansible_facts.packages'
  tags:
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - configure_bind_crypto_policy
  - configure_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

- name: Configure BIND to use System Crypto Policy - Aborting remediation, file not
    found
  ansible.builtin.debug:
    msg: Aborting remediation as '/etc/named.conf' was not found.
  when:
  - '"bind" in ansible_facts.packages'
  - not bind_config_file.stat.exists
  tags:
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - configure_bind_crypto_policy
  - configure_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

- name: Configure BIND to use System Crypto Policy - Insert crypto-policy into BIND
    config
  ansible.builtin.lineinfile:
    path: /etc/named.conf
    insertafter: ^\s*options\s*{
    line: ' include "/etc/crypto-policies/back-ends/bind.config";'
    state: present
  when:
  - '"bind" in ansible_facts.packages'
  - bind_config_file.stat.exists
  tags:
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - configure_bind_crypto_policy
  - configure_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

Rule Configure System Cryptography Policy [ref]

To configure the system cryptography policy to use ciphers only from the FIPS:OSPP policy, run the following command:

$ sudo update-crypto-policies --set FIPS:OSPP

The rule checks if settings for selected crypto policy are configured as expected. Configuration files in the /etc/crypto-policies/back-ends are either symlinks to correct files provided by Crypto-policies package or they are regular files in case crypto policy customizations are applied. Crypto policies may be customized by crypto policy modules, in which case it is delimited from the base policy using a colon.

Warning: The system needs to be rebooted for these changes to take effect.

Rationale:

Centralized cryptographic policies simplify applying secure ciphers across an operating system and the applications that run on that operating system. Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_configure_crypto_policy

References:

disa	CCI-000068, CCI-003123, CCI-002450, CCI-000877, CCI-002418, CCI-001453, CCI-002890
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.312(e)(1), 164.312(e)(2)(ii)
ism	1446
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1
nist	AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13, SC-12(2), SC-12(3)
ospp	FCS_COP.1(1), FCS_COP.1(2), FCS_COP.1(3), FCS_COP.1(4), FCS_CKM.1, FCS_CKM.2, FCS_TLSC_EXT.1
os-srg	SRG-OS-000396-GPOS-00176, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174
pcidss4	2.2.7, 2.2

Remediation Shell script ⇲


var_system_crypto_policy='FIPS:OSPP'


stderr_of_call=$(update-crypto-policies --set ${var_system_crypto_policy} 2>&1 > /dev/null)
rc=$?

if test "$rc" = 127; then
	echo "$stderr_of_call" >&2
	echo "Make sure that the script is installed on the remediated system." >&2
	echo "See output of the 'dnf provides update-crypto-policies' command" >&2
	echo "to see what package to (re)install" >&2

	false  # end with an error code
elif test "$rc" != 0; then
	echo "Error invoking the update-crypto-policies script: $stderr_of_call" >&2
	false  # end with an error code
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: XCCDF Value var_system_crypto_policy # promote to variable
  set_fact:
    var_system_crypto_policy: !!str FIPS:OSPP
  tags:
    - always

- name: Configure System Cryptography Policy
  lineinfile:
    path: /etc/crypto-policies/config
    regexp: ^(?!#)(\S+)$
    line: '{{ var_system_crypto_policy }}'
    create: true
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.7
  - configure_crypto_policy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Verify that Crypto Policy is Set (runtime)
  command: /usr/bin/update-crypto-policies --set {{ var_system_crypto_policy }}
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.7
  - configure_crypto_policy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

Rule Configure Kerberos to use System Crypto Policy [ref]

Crypto Policies provide a centralized control over crypto algorithms usage of many packages. Kerberos is supported by crypto policy, but it's configuration may be set up to ignore it. To check that Crypto Policies settings for Kerberos are configured correctly, examine that there is a symlink at /etc/krb5.conf.d/crypto-policies targeting /etc/cypto-policies/back-ends/krb5.config. If the symlink exists, Kerberos is configured to use the system-wide crypto policy settings.

Rationale:

Overriding the system crypto policy makes the behavior of Kerberos violate expectations, and makes system configuration more fragmented.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_configure_kerberos_crypto_policy

References:

disa	CCI-000803
ism	0418, 1055, 1402
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1
nist	SC-13, SC-12(2), SC-12(3)
os-srg	SRG-OS-000120-GPOS-00061

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	configure


rm -f /etc/krb5.conf.d/crypto-policies
ln -s /etc/crypto-policies/back-ends/krb5.config /etc/krb5.conf.d/crypto-policies

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	configure

- name: Configure Kerberos to use System Crypto Policy
  file:
    src: /etc/crypto-policies/back-ends/krb5.config
    path: /etc/krb5.conf.d/crypto-policies
    state: link
  tags:
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - configure_kerberos_crypto_policy
  - configure_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - reboot_required

Rule Configure Libreswan to use System Crypto Policy [ref]

Crypto Policies provide a centralized control over crypto algorithms usage of many packages. Libreswan is supported by system crypto policy, but the Libreswan configuration may be set up to ignore it. To check that Crypto Policies settings are configured correctly, ensure that the /etc/ipsec.conf includes the appropriate configuration file. In /etc/ipsec.conf, make sure that the following line is not commented out or superseded by later includes: include /etc/crypto-policies/back-ends/libreswan.config

Rationale:

Overriding the system crypto policy makes the behavior of the Libreswan service violate expectations, and makes system configuration more fragmented.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_configure_libreswan_crypto_policy

References:

disa	CCI-000068
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1
nist	CM-6(a), MA-4(6), SC-13, SC-12(2), SC-12(3)
pcidss	Req-2.2
os-srg	SRG-OS-000033-GPOS-00014

Remediation Shell script ⇲


function remediate_libreswan_crypto_policy() {
    CONFIG_FILE="/etc/ipsec.conf"
    if ! grep -qP "^\s*include\s+/etc/crypto-policies/back-ends/libreswan.config\s*(?:#.*)?$" "$CONFIG_FILE" ; then
        # the file might not end with a new line
        echo -e '\ninclude /etc/crypto-policies/back-ends/libreswan.config' >> "$CONFIG_FILE"
    fi
    return 0
}

remediate_libreswan_crypto_policy

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Configure Libreswan to use System Crypto Policy
  lineinfile:
    path: /etc/ipsec.conf
    line: include /etc/crypto-policies/back-ends/libreswan.config
    create: true
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSS-Req-2.2
  - configure_libreswan_crypto_policy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

Rule Configure OpenSSL library to use System Crypto Policy [ref]

Crypto Policies provide a centralized control over crypto algorithms usage of many packages. OpenSSL is supported by crypto policy, but the OpenSSL configuration may be set up to ignore it. To check that Crypto Policies settings are configured correctly, you have to examine the OpenSSL config file available under /etc/pki/tls/openssl.cnf. This file has the ini format, and it enables crypto policy support if there is a [ crypto_policy ] section that contains the .include /etc/crypto-policies/back-ends/opensslcnf.config directive.

Rationale:

Overriding the system crypto policy makes the behavior of the Java runtime violates expectations, and makes system configuration more fragmented.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_configure_openssl_crypto_policy

References:

disa	CCI-001453
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1
nist	AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13, SC-12(2), SC-12(3)
pcidss	Req-2.2
os-srg	SRG-OS-000250-GPOS-00093

Remediation Shell script ⇲


OPENSSL_CRYPTO_POLICY_SECTION='[ crypto_policy ]'
OPENSSL_CRYPTO_POLICY_SECTION_REGEX='\[\s*crypto_policy\s*\]'

OPENSSL_CRYPTO_POLICY_INCLUSION='.include /etc/crypto-policies/back-ends/opensslcnf.config'

OPENSSL_CRYPTO_POLICY_INCLUSION_REGEX='^\s*\.include\s*(?:=\s*)?/etc/crypto-policies/back-ends/opensslcnf.config$'



  


function remediate_openssl_crypto_policy() {
	CONFIG_FILE=/etc/pki/tls/openssl.cnf
	if test -f "$CONFIG_FILE"; then
		if ! grep -q "^\\s*$OPENSSL_CRYPTO_POLICY_SECTION_REGEX" "$CONFIG_FILE"; then
			printf '\n%s\n\n%s' "$OPENSSL_CRYPTO_POLICY_SECTION" "$OPENSSL_CRYPTO_POLICY_INCLUSION" >> "$CONFIG_FILE"
			return 0
		elif ! grep -q "^\\s*$OPENSSL_CRYPTO_POLICY_INCLUSION_REGEX" "$CONFIG_FILE"; then
			sed -i "s|$OPENSSL_CRYPTO_POLICY_SECTION_REGEX|&\\n\\n$OPENSSL_CRYPTO_POLICY_INCLUSION\\n|" "$CONFIG_FILE"
			return 0
		fi
	else
		echo "Aborting remediation as '$CONFIG_FILE' was not even found." >&2
		return 1
	fi
}

remediate_openssl_crypto_policy

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	unknown

- name: Configure OpenSSL library to use System Crypto Policy - Search for crypto_policy
    Section
  ansible.builtin.find:
    paths: /etc/pki/tls
    patterns: openssl.cnf
    contains: ^\s*\[\s*crypto_policy\s*]
  register: test_crypto_policy_group
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSS-Req-2.2
  - configure_openssl_crypto_policy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy

- name: Configure OpenSSL library to use System Crypto Policy - Search for crypto_policy
    Section Together With .include Directive
  ansible.builtin.find:
    paths: /etc/pki/tls
    patterns: openssl.cnf
    contains: ^\s*\.include\s*(?:=\s*)?/etc/crypto-policies/back-ends/opensslcnf.config$
  register: test_crypto_policy_include_directive
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSS-Req-2.2
  - configure_openssl_crypto_policy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy

- name: Configure OpenSSL library to use System Crypto Policy - Add .include Line
    for opensslcnf.config File in crypto_policy Section
  ansible.builtin.lineinfile:
    create: true
    insertafter: ^\s*\[\s*crypto_policy\s*]\s*
    line: .include /etc/crypto-policies/back-ends/opensslcnf.config
    path: /etc/pki/tls/openssl.cnf
  when:
  - test_crypto_policy_group.matched > 0
  - test_crypto_policy_include_directive.matched == 0
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSS-Req-2.2
  - configure_openssl_crypto_policy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy

- name: Configure OpenSSL library to use System Crypto Policy - Add crypto_policy
    Section With .include for opensslcnf.config File
  ansible.builtin.lineinfile:
    create: true
    line: |-
      [crypto_policy]
      .include /etc/crypto-policies/back-ends/opensslcnf.config
    path: /etc/pki/tls/openssl.cnf
  when: test_crypto_policy_group.matched == 0
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - PCI-DSS-Req-2.2
  - configure_openssl_crypto_policy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy

Rule Configure SSH to use System Crypto Policy [ref]

Crypto Policies provide a centralized control over crypto algorithms usage of many packages. SSH is supported by crypto policy, but the SSH configuration may be set up to ignore it. To check that Crypto Policies settings are configured correctly, ensure that the CRYPTO_POLICY variable is either commented or not set at all in the /etc/sysconfig/sshd.

Rationale:

Overriding the system crypto policy makes the behavior of the SSH service violate expectations, and makes system configuration more fragmented.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_configure_ssh_crypto_policy

References:

disa	CCI-001453
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.312(e)(1), 164.312(e)(2)(ii)
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1
nist	AC-17(a), AC-17(2), CM-6(a), MA-4(6), SC-13
ospp	FCS_SSH_EXT.1, FCS_SSHS_EXT.1, FCS_SSHC_EXT.1
pcidss	Req-2.2
os-srg	SRG-OS-000250-GPOS-00093
pcidss4	2.2.7, 2.2

Remediation Shell script ⇲


SSH_CONF="/etc/sysconfig/sshd"

sed -i "/^\s*CRYPTO_POLICY.*$/Id" $SSH_CONF

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Configure SSH to use System Crypto Policy
  lineinfile:
    dest: /etc/sysconfig/sshd
    state: absent
    regexp: (?i)^\s*CRYPTO_POLICY.*$
  tags:
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(6)
  - NIST-800-53-SC-13
  - PCI-DSS-Req-2.2
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.7
  - configure_ssh_crypto_policy
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required

Group Operating System Vendor Support and Certification Group contains 1 rule

[ref] The assurance of a vendor to provide operating system support and maintenance for their product is an important criterion to ensure product stability and security over the life of the product. A certified product that follows the necessary standards and government certification requirements guarantees that known software vulnerabilities will be remediated, and proper guidance for protecting and securing the operating system will be given.

Rule The Installed Operating System Is FIPS 140-2 Certified [ref]

To enable processing of sensitive information the operating system must provide certified cryptographic modules compliant with FIPS 140-2 standard.

Warning: There is no remediation besides switching to a different operating system.

Rationale:

The Federal Information Processing Standard (FIPS) Publication 140-2, (FIPS PUB 140-2) is a computer security standard. The standard specifies security requirements for cryptographic modules used to protect sensitive unclassified information. Refer to the full FIPS 140-2 standard at http://csrc.nist.gov/publications/fips/fips140-2/fips1402.pdf for further details on the requirements. FIPS 140-2 validation is required by U.S. law when information systems use cryptography to protect sensitive government information. In order to achieve FIPS 140-2 certification, cryptographic modules are subject to extensive testing by independent laboratories, accredited by National Institute of Standards and Technology (NIST).

Severity:

high

Rule ID:

xccdf_org.ssgproject.content_rule_installed_OS_is_FIPS_certified

References:

disa	CCI-000803, CCI-002450
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1
nist	SC-12(2), SC-12(3), IA-7, SC-13, CM-6(a), SC-12

Group Endpoint Protection Software Group contains 2 rules

[ref] Endpoint protection security software that is not provided or supported by Red Hat can be installed to provide complementary or duplicative security capabilities to those provided by the base platform. Add-on software may not be appropriate for some specialized systems.

Rule Install Virus Scanning Software [ref]

Virus scanning software can be used to protect a system from penetration from computer viruses and to limit their spread through intermediate systems. The virus scanning software should be configured to perform scans dynamically on accessed files. If this capability is not available, the system must be configured to scan, at a minimum, all altered files on the system on a daily basis. If the system processes inbound SMTP mail, the virus scanner must be configured to scan all received mail.

Rationale:

Virus scanning software can be used to detect if a system has been compromised by computer viruses, as well as to limit their spread to other systems.

Severity:

high

Rule ID:

xccdf_org.ssgproject.content_rule_install_antivirus

References:

cis-csc	12, 13, 14, 4, 7, 8
cobit5	APO01.06, APO13.02, BAI02.01, BAI06.01, DSS04.07, DSS05.01, DSS05.02, DSS05.03, DSS06.06
disa	CCI-000366, CCI-001239, CCI-001668
isa-62443-2009	4.3.4.3.8, 4.4.3.2
isa-62443-2013	SR 3.2, SR 3.3, SR 3.4, SR 4.1
iso27001-2013	A.12.2.1, A.14.2.8, A.8.2.3
nist	CM-6(a)
nist-csf	DE.CM-4, DE.DP-3, PR.DS-1
os-srg	SRG-OS-000480-GPOS-00227

Rule Install Intrusion Detection Software [ref]

The base Red Hat Virtualization 4 platform already includes a sophisticated auditing system that can detect intruder activity, as well as SELinux, which provides host-based intrusion prevention capabilities by confining privileged programs and user sessions which may become compromised.

Warning: In DoD environments, supplemental intrusion detection and antivirus tools, such as the McAfee Host-based Security System, are available to integrate with existing infrastructure. Per DISA guidance, when these supplemental tools interfere with proper functioning of SELinux, SELinux takes precedence. Should further clarification be required, DISA contact information is published publicly at https://public.cyber.mil/stigs/

Rationale:

Host-based intrusion detection tools provide a system-level defense when an intruder gains access to a system or network.

Severity:

high

Rule ID:

xccdf_org.ssgproject.content_rule_install_hids

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 7, 8, 9
cobit5	APO01.06, APO13.01, DSS01.03, DSS01.05, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02
disa	CCI-001263
isa-62443-2009	4.3.3.4
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a)
nist-csf	DE.CM-1, PR.AC-5, PR.DS-5, PR.PT-4
pcidss	Req-11.4

Group Disk Partitioning Group contains 5 rules

[ref] To ensure separation and protection of data, there are top-level system directories which should be placed on their own physical partition or logical volume. The installer's default partitioning scheme creates separate logical volumes for /, /boot, and swap.

If starting with any of the default layouts, check the box to \"Review and modify partitioning.\" This allows for the easy creation of additional logical volumes inside the volume group already created, though it may require making /'s logical volume smaller to create space. In general, using logical volumes is preferable to using partitions because they can be more easily adjusted later.
If creating a custom layout, create the partitions mentioned in the previous paragraph (which the installer will require anyway), as well as separate ones described in the following sections.

If a system has already been installed, and the default partitioning scheme was used, it is possible but nontrivial to modify it to create separate logical volumes for the directories listed above. The Logical Volume Manager (LVM) makes this possible.

Rule Encrypt Partitions [ref]

Red Hat Virtualization 4 natively supports partition encryption through the Linux Unified Key Setup-on-disk-format (LUKS) technology. The easiest way to encrypt a partition is during installation time.

For manual installations, select the Encrypt checkbox during partition creation to encrypt the partition. When this option is selected the system will prompt for a passphrase to use in decrypting the partition. The passphrase will subsequently need to be entered manually every time the system boots.

For automated/unattended installations, it is possible to use Kickstart by adding the --encrypted and --passphrase= options to the definition of each partition to be encrypted. For example, the following line would encrypt the root partition:

part / --fstype=ext4 --size=100 --onpart=hda1 --encrypted --passphrase=PASSPHRASE

Any PASSPHRASE is stored in the Kickstart in plaintext, and the Kickstart must then be protected accordingly. Omitting the --passphrase= option from the partition definition will cause the installer to pause and interactively ask for the passphrase during installation.

By default, the Anaconda installer uses aes-xts-plain64 cipher with a minimum 512 bit key size which should be compatible with FIPS enabled.

Detailed information on encrypting partitions using LUKS or LUKS ciphers can be found on the Red Hat Virtualization 4 Documentation web site:
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/security_hardening/encrypting-block-devices-using-luks_security-hardening .

Rationale:

The risk of a system's physical compromise, particularly mobile systems such as laptops, places its data at risk of compromise. Encrypting this data mitigates the risk of its loss if the system is lost.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_encrypt_partitions

References:

cis-csc	13, 14
cobit5	APO01.06, BAI02.01, BAI06.01, DSS04.07, DSS05.03, DSS05.04, DSS05.07, DSS06.02, DSS06.06
cui	3.13.16
disa	CCI-002476, CCI-001199, CCI-002475
hipaa	164.308(a)(1)(ii)(D), 164.308(b)(1), 164.310(d), 164.312(a)(1), 164.312(a)(2)(iii), 164.312(a)(2)(iv), 164.312(b), 164.312(c), 164.314(b)(2)(i), 164.312(d)
isa-62443-2013	SR 3.4, SR 4.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R4.2, CIP-007-3 R5.1
nist	CM-6(a), SC-28, SC-28(1), SC-13, AU-9(3)
nist-csf	PR.DS-1, PR.DS-5
os-srg	SRG-OS-000405-GPOS-00184, SRG-OS-000185-GPOS-00079, SRG-OS-000404-GPOS-00183

Rule Ensure /home Located On Separate Partition [ref]

If user home directories will be stored locally, create a separate partition for /home at installation time (or migrate it later using LVM). If /home will be mounted from another system such as an NFS server, then creating a separate partition is not necessary at installation time, and the mountpoint can instead be configured later.

Rationale:

Ensuring that /home is mounted on its own partition enables the setting of more restrictive mount options, and also helps ensure that users cannot trivially fill partitions used for log or audit data storage.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_partition_for_home

References:

cis-csc	12, 15, 8
cobit5	APO13.01, DSS05.02
disa	CCI-000366
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.13.1.1, A.13.2.1, A.14.1.3
nist	CM-6(a), SC-5(2)
nist-csf	PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R28

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	high
Reboot:	false
Strategy:	enable


part /home

Rule Ensure /tmp Located On Separate Partition [ref]

The /tmp directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volume at installation time, or migrate it using LVM.

Rationale:

The /tmp partition is used as temporary storage by many programs. Placing /tmp in its own partition enables the setting of more restrictive mount options, which can help protect programs which use it.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_partition_for_tmp

References:

cis-csc	12, 15, 8
cobit5	APO13.01, DSS05.02
disa	CCI-000366
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.13.1.1, A.13.2.1, A.14.1.3
nist	CM-6(a), SC-5(2)
nist-csf	PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	high
Reboot:	false
Strategy:	enable


part /tmp

Rule Ensure /var Located On Separate Partition [ref]

The /var directory is used by daemons and other system services to store frequently-changing data. Ensure that /var has its own partition or logical volume at installation time, or migrate it using LVM.

Rationale:

Ensuring that /var is mounted on its own partition enables the setting of more restrictive mount options. This helps protect system services such as daemons or other programs which use it. It is not uncommon for the /var directory to contain world-writable directories installed by other software packages.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_partition_for_var

References:

cis-csc	12, 15, 8
cobit5	APO13.01, DSS05.02
disa	CCI-000366
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.13.1.1, A.13.2.1, A.14.1.3
nist	CM-6(a), SC-5(2)
nist-csf	PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R28

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	high
Reboot:	false
Strategy:	enable


part /var

Rule Ensure /var/log/audit Located On Separate Partition [ref]

Audit logs are stored in the /var/log/audit directory. Ensure that /var/log/audit has its own partition or logical volume at installation time, or migrate it using LVM. Make absolutely certain that it is large enough to store all audit logs that will be created by the auditing daemon.

Rationale:

Placing /var/log/audit in its own partition enables better separation between audit files and other files, and helps ensure that auditing cannot be halted due to the partition running out of space.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_partition_for_var_log_audit

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 8
cobit5	APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.02, DSS05.04, DSS05.07, MEA02.01
disa	CCI-000366, CCI-001849
hipaa	164.312(a)(2)(ii)
isa-62443-2009	4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.17.2.1
nerc-cip	CIP-007-3 R6.5
nist	CM-6(a), AU-4, SC-5(2)
nist-csf	PR.DS-4, PR.PT-1, PR.PT-4
ospp	FMT_SMF_EXT.1
os-srg	SRG-OS-000341-GPOS-00132, SRG-OS-000480-GPOS-00227
app-srg-ctr	SRG-APP-000357-CTR-000800
anssi	R71

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	high
Reboot:	false
Strategy:	enable


part /var/log/audit

Group GNOME Desktop Environment Group contains 1 rule

[ref] GNOME is a graphical desktop environment bundled with many Linux distributions that allow users to easily interact with the operating system graphically rather than textually. The GNOME Graphical Display Manager (GDM) provides login, logout, and user switching contexts as well as display server management.

GNOME is developed by the GNOME Project and is considered the default Red Hat Graphical environment.

For more information on GNOME and the GNOME Project, see https://www.gnome.org.

Rule Remove the GDM Package Group [ref]

By removing the gdm package, the system no longer has GNOME installed installed. If X Windows is not installed then the system cannot boot into graphical user mode. This prevents the system from being accidentally or maliciously booted into a graphical.target mode. To do so, run the following command:

$ sudo yum remove gdm

Rationale:

Unnecessary service packages must not be installed to decrease the attack surface of the system. A graphical environment is unnecessary for certain types of systems including a virtualization hypervisor.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_gdm_removed

References:

nist	CM-7(a), CM-7(b), CM-6(a)
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q gdm; then

# CAUTION: This remediation script will remove gdm
#	   from the system, and may remove any packages
#	   that depend on gdm. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "gdm" ; then
yum remove -y "gdm"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_gdm_removed

- name: Ensure gdm is removed
  package:
    name: gdm
    state: absent
  when: '"gdm" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_gdm_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=gdm

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_gdm

class remove_gdm {
  package { 'gdm':
    ensure => 'purged',
  }
}

Group Sudo Group contains 2 rules

[ref] Sudo, which stands for "su 'do'", provides the ability to delegate authority to certain users, groups of users, or system administrators. When configured for system users and/or groups, Sudo can allow a user or group to execute privileged commands that normally only root is allowed to execute.

For more information on Sudo and addition Sudo configuration options, see https://www.sudo.ws.

Rule Ensure Users Re-Authenticate for Privilege Escalation - sudo !authenticate [ref]

The sudo !authenticate option, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that the !authenticate option does not exist in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/.

Rationale:

Without re-authentication, users may access resources or perform tasks for which they do not have authorization.

When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sudo_remove_no_authenticate

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004895
isa-62443-2009	4.3.3.5.1, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-11, CM-6(a)
nist-csf	PR.AC-1, PR.AC-7
os-srg	SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


for f in /etc/sudoers /etc/sudoers.d/* ; do
  if [ ! -e "$f" ] ; then
    continue
  fi
  matching_list=$(grep -P '^(?!#).*[\s]+\!authenticate.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      # comment out "!authenticate" matches to preserve user data
      sed -i "s/^${entry}$/# &/g" $f
    done <<< "$matching_list"

    /usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
  fi
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Find /etc/sudoers.d/ files
  ansible.builtin.find:
    paths:
    - /etc/sudoers.d/
  register: sudoers
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-11
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_remove_no_authenticate

- name: Remove lines containing !authenticate from sudoers files
  ansible.builtin.replace:
    regexp: (^(?!#).*[\s]+\!authenticate.*$)
    replace: '# \g<1>'
    path: '{{ item.path }}'
    validate: /usr/sbin/visudo -cf %s
  with_items:
  - path: /etc/sudoers
  - '{{ sudoers.files }}'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-11
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_remove_no_authenticate

Rule Only the VDSM User Can Use sudo NOPASSWD [ref]
The sudo `NOPASSWD` tag, when specified, allows a user to execute commands using sudo without having to authenticate. Only the `vdsm` user should have this capability in any sudo configuration snippets in `/etc/sudoers.d/`.
Rationale:	Without re-authentication, users may access resources or perform tasks for which they do not have authorization. When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.
Severity:	medium
Rule ID:	xccdf_org.ssgproject.content_rule_sudo_vdsm_nopasswd

Group Updating Software Group contains 6 rules

[ref] The yum command line tool is used to install and update software packages. The system also provides a graphical software update tool in the System menu, in the Administration submenu, called Software Update.

Red Hat Virtualization 4 systems contain an installed software catalog called the RPM database, which records metadata of installed packages. Consistently using yum or the graphical Software Update for all software installation allows for insight into the current inventory of installed software on the system.

Rule Ensure yum Removes Previous Package Versions [ref]

yum should be configured to remove previous software components after new versions have been installed. To configure yum to remove the previous software components after updating, set the clean_requirements_on_remove to 1 in /etc/yum.conf.

Rationale:

Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by some adversaries.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_clean_components_post_updating

References:

cis-csc	18, 20, 4
cobit5	APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02
cui	3.4.8
disa	CCI-002617
isa-62443-2009	4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9
iso27001-2013	A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3
nist	SI-2(6), CM-11(a), CM-11(b), CM-6(a)
nist-csf	ID.RA-1, PR.IP-12
os-srg	SRG-OS-000437-GPOS-00194

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q yum; then

if grep --silent ^clean_requirements_on_remove /etc/yum.conf ; then
        sed -i "s/^clean_requirements_on_remove.*/clean_requirements_on_remove=1/g" /etc/yum.conf
else
        echo -e "\n# Set clean_requirements_on_remove to 1 per security requirements" >> /etc/yum.conf
        echo "clean_requirements_on_remove=1" >> /etc/yum.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-11(a)
  - NIST-800-53-CM-11(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-2(6)
  - clean_components_post_updating
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure yum Removes Previous Package Versions - Ensure YUM Removes Previous
    Package Versions
  ansible.builtin.lineinfile:
    dest: /etc/yum.conf
    regexp: ^#?clean_requirements_on_remove
    line: clean_requirements_on_remove=1
    insertafter: \[main\]
    create: true
  when: '"yum" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-11(a)
  - NIST-800-53-CM-11(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-2(6)
  - clean_components_post_updating
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure gpgcheck Enabled In Main yum Configuration [ref]

The gpgcheck option controls whether RPM packages' signatures are always checked prior to installation. To configure yum to check package signatures before installing them, ensure the following line appears in /etc/yum.conf in the [main] section:

gpgcheck=1

Rationale:

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization.
Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA).

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_ensure_gpgcheck_globally_activated

References:

cis-csc	11, 2, 3, 9
cjis	5.10.4.1
cobit5	APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02
cui	3.4.8
disa	CCI-003992
hipaa	164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i)
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6
iso27001-2013	A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4
nist	CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b)
nist-csf	PR.DS-6, PR.DS-8, PR.IP-1
ospp	FPT_TUD_EXT.1, FPT_TUD_EXT.2
pcidss	Req-6.2
os-srg	SRG-OS-000366-GPOS-00153
anssi	R59
pcidss4	6.3.3, 6.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q yum; then

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^gpgcheck")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^gpgcheck\\>" "/etc/yum.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^gpgcheck\\>.*/$escaped_formatted_output/gi" "/etc/yum.conf"
else
    if [[ -s "/etc/yum.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/yum.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/yum.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/yum.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-11(a)
  - NIST-800-53-CM-11(b)
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SA-12
  - NIST-800-53-SA-12(10)
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SI-7
  - PCI-DSS-Req-6.2
  - PCI-DSSv4-6.3
  - PCI-DSSv4-6.3.3
  - configure_strategy
  - ensure_gpgcheck_globally_activated
  - high_severity
  - low_complexity
  - medium_disruption
  - no_reboot_needed

- name: Ensure GPG check is globally activated
  ini_file:
    dest: /etc/yum.conf
    section: main
    option: gpgcheck
    value: 1
    no_extra_spaces: true
    create: false
  when: '"yum" in ansible_facts.packages'
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-11(a)
  - NIST-800-53-CM-11(b)
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SA-12
  - NIST-800-53-SA-12(10)
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SI-7
  - PCI-DSS-Req-6.2
  - PCI-DSSv4-6.3
  - PCI-DSSv4-6.3.3
  - configure_strategy
  - ensure_gpgcheck_globally_activated
  - high_severity
  - low_complexity
  - medium_disruption
  - no_reboot_needed

Rule Ensure gpgcheck Enabled for Local Packages [ref]

yum should be configured to verify the signature(s) of local packages prior to installation. To configure yum to verify signatures of local packages, set the localpkg_gpgcheck to 1 in /etc/yum.conf.

Rationale:

Changes to any software components can have significant effects to the overall security of the operating system. This requirement ensures the software has not been tampered and has been provided by a trusted vendor.

Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_ensure_gpgcheck_local_packages

References:

cis-csc	11, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05
cui	3.4.8
disa	CCI-003992
hipaa	164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i)
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4
nist	CM-11(a), CM-11(b), CM-6(a), CM-5(3), SA-12, SA-12(10)
nist-csf	PR.IP-1
ospp	FPT_TUD_EXT.1, FPT_TUD_EXT.2
os-srg	SRG-OS-000366-GPOS-00153
anssi	R59

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q yum; then

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^localpkg_gpgcheck")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^localpkg_gpgcheck\\>" "/etc/yum.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^localpkg_gpgcheck\\>.*/$escaped_formatted_output/gi" "/etc/yum.conf"
else
    if [[ -s "/etc/yum.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/yum.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/yum.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/yum.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	unknown

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-11(a)
  - NIST-800-53-CM-11(b)
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SA-12
  - NIST-800-53-SA-12(10)
  - ensure_gpgcheck_local_packages
  - high_severity
  - low_complexity
  - medium_disruption
  - no_reboot_needed
  - unknown_strategy

- name: Ensure GPG check Enabled for Local Packages (yum)
  block:

  - name: Check stats of yum
    stat:
      path: /etc/yum.conf
    register: pkg

  - name: Check if config file of yum is a symlink
    ansible.builtin.set_fact:
      pkg_config_file_symlink: '{{ pkg.stat.lnk_target if pkg.stat.lnk_target is match("^/.*")
        else "/etc/yum.conf" | dirname ~ "/" ~ pkg.stat.lnk_target }}'
    when: pkg.stat.lnk_target is defined

  - name: Ensure GPG check Enabled for Local Packages (yum)
    ini_file:
      dest: '{{ pkg_config_file_symlink |  default("/etc/yum.conf") }}'
      section: main
      option: localpkg_gpgcheck
      value: 1
      no_extra_spaces: true
      create: true
  when: '"yum" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-11(a)
  - NIST-800-53-CM-11(b)
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SA-12
  - NIST-800-53-SA-12(10)
  - ensure_gpgcheck_local_packages
  - high_severity
  - low_complexity
  - medium_disruption
  - no_reboot_needed
  - unknown_strategy

Rule Ensure gpgcheck Enabled for All yum Package Repositories [ref]

To ensure signature checking is not disabled for any repos, remove any lines from files in /etc/yum.repos.d of the form:

gpgcheck=0

Rationale:

Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA)."

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_ensure_gpgcheck_never_disabled

References:

cis-csc	11, 2, 3, 9
cjis	5.10.4.1
cobit5	APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02
cui	3.4.8
disa	CCI-003992
hipaa	164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i)
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6
iso27001-2013	A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4
nist	CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b)
nist-csf	PR.DS-6, PR.DS-8, PR.IP-1
ospp	FPT_TUD_EXT.1, FPT_TUD_EXT.2
pcidss	Req-6.2
os-srg	SRG-OS-000366-GPOS-00153
anssi	R59
pcidss4	6.3.3, 6.3

Remediation Shell script ⇲


sed -i 's/gpgcheck\s*=.*/gpgcheck=1/g' /etc/yum.repos.d/*

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	enable

- name: Grep for yum repo section names
  shell: |
    set -o pipefail
    grep -HEr '^\[.+\]' -r /etc/yum.repos.d/
  register: repo_grep_results
  failed_when: repo_grep_results.rc not in [0, 1]
  changed_when: false
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-11(a)
  - NIST-800-53-CM-11(b)
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SA-12
  - NIST-800-53-SA-12(10)
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SI-7
  - PCI-DSS-Req-6.2
  - PCI-DSSv4-6.3
  - PCI-DSSv4-6.3.3
  - enable_strategy
  - ensure_gpgcheck_never_disabled
  - high_severity
  - low_complexity
  - medium_disruption
  - no_reboot_needed

- name: Set gpgcheck=1 for each yum repo
  ini_file:
    path: '{{ item[0] }}'
    section: '{{ item[1] }}'
    option: gpgcheck
    value: '1'
    no_extra_spaces: true
  loop: '{{ repo_grep_results.stdout |regex_findall( ''(.+\.repo):\[(.+)\]\n?'' )
    if repo_grep_results is not skipped else [] }}'
  when: repo_grep_results is not skipped
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-11(a)
  - NIST-800-53-CM-11(b)
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SA-12
  - NIST-800-53-SA-12(10)
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SI-7
  - PCI-DSS-Req-6.2
  - PCI-DSSv4-6.3
  - PCI-DSSv4-6.3.3
  - enable_strategy
  - ensure_gpgcheck_never_disabled
  - high_severity
  - low_complexity
  - medium_disruption
  - no_reboot_needed

Rule Ensure Red Hat GPG Key Installed [ref]

To ensure the system can cryptographically verify base software packages come from Red Hat (and to connect to the Red Hat Network to receive them), the Red Hat GPG key must properly be installed. To install the Red Hat GPG key, run:

$ sudo subscription-manager register

If the system is not connected to the Internet or an RHN Satellite, then install the Red Hat GPG key from trusted media such as the Red Hat installation CD-ROM or DVD. Assuming the disc is mounted in /media/cdrom, use the following command as the root user to import it into the keyring:

$ sudo rpm --import /media/cdrom/RPM-GPG-KEY

Alternatively, the key may be pre-loaded during the RHEL installation. In such cases, the key can be installed by running the following command:

sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

Rationale:

Changes to software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. The Red Hat GPG key is necessary to cryptographically verify packages are from Red Hat.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_ensure_redhat_gpgkey_installed

References:

cis-csc	11, 2, 3, 9
cjis	5.10.4.1
cobit5	APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02
cui	3.4.8
disa	CCI-003992
hipaa	164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i)
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4
isa-62443-2013	SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6
iso27001-2013	A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4
nerc-cip	CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1
nist	CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a)
nist-csf	PR.DS-6, PR.DS-8, PR.IP-1
ospp	FPT_TUD_EXT.1, FPT_TUD_EXT.2
pcidss	Req-6.2
os-srg	SRG-OS-000366-GPOS-00153
anssi	R59
pcidss4	6.3.3, 6.3

Remediation Shell script ⇲

# The two fingerprints below are retrieved from https://access.redhat.com/security/team/key
readonly REDHAT_RELEASE_FINGERPRINT="567E347AD0044ADE55BA8A5F199E2F91FD431D51"
readonly REDHAT_AUXILIARY_FINGERPRINT="6A6AA7C97C8890AEC6AEBFE2F76F66C3D4082792"

# Location of the key we would like to import (once it's integrity verified)
readonly REDHAT_RELEASE_KEY="/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release"

RPM_GPG_DIR_PERMS=$(stat -c %a "$(dirname "$REDHAT_RELEASE_KEY")")

# Verify /etc/pki/rpm-gpg directory permissions are safe
if [ "${RPM_GPG_DIR_PERMS}" -le "755" ]
then
  # If they are safe, try to obtain fingerprints from the key file
  # (to ensure there won't be e.g. CRC error).

  readarray -t GPG_OUT < <(gpg --show-keys --with-fingerprint --with-colons "$REDHAT_RELEASE_KEY" | grep -A1 "^pub" | grep "^fpr" | cut -d ":" -f 10)

  GPG_RESULT=$?
  # No CRC error, safe to proceed
  if [ "${GPG_RESULT}" -eq "0" ]
  then
    echo "${GPG_OUT[*]}" | grep -vE "${REDHAT_RELEASE_FINGERPRINT}|${REDHAT_AUXILIARY_FINGERPRINT}" || {
      # If $REDHAT_RELEASE_KEY file doesn't contain any keys with unknown fingerprint, import it
      rpm --import "${REDHAT_RELEASE_KEY}"
    }
  fi
fi

Remediation Ansible snippet ⇲

Complexity:	medium
Disruption:	medium
Reboot:	false
Strategy:	restrict

- name: Read permission of GPG key directory
  stat:
    path: /etc/pki/rpm-gpg/
  register: gpg_key_directory_permission
  check_mode: false
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SI-7
  - PCI-DSS-Req-6.2
  - PCI-DSSv4-6.3
  - PCI-DSSv4-6.3.3
  - ensure_redhat_gpgkey_installed
  - high_severity
  - medium_complexity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Read signatures in GPG key
  command: gpg --with-fingerprint --with-colons "/etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release"
  changed_when: false
  register: gpg_fingerprints
  check_mode: false
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SI-7
  - PCI-DSS-Req-6.2
  - PCI-DSSv4-6.3
  - PCI-DSSv4-6.3.3
  - ensure_redhat_gpgkey_installed
  - high_severity
  - medium_complexity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Set Fact - Installed GPG Fingerprints
  set_fact:
    gpg_installed_fingerprints: |-
      {{ gpg_fingerprints.stdout | regex_findall('^pub.*
      (?:^fpr[:]*)([0-9A-Fa-f]*)', '\1') | list }}
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SI-7
  - PCI-DSS-Req-6.2
  - PCI-DSSv4-6.3
  - PCI-DSSv4-6.3.3
  - ensure_redhat_gpgkey_installed
  - high_severity
  - medium_complexity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Set Fact - Valid fingerprints
  set_fact:
    gpg_valid_fingerprints:
    - 567E347AD0044ADE55BA8A5F199E2F91FD431D51
    - 6A6AA7C97C8890AEC6AEBFE2F76F66C3D4082792
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SI-7
  - PCI-DSS-Req-6.2
  - PCI-DSSv4-6.3
  - PCI-DSSv4-6.3.3
  - ensure_redhat_gpgkey_installed
  - high_severity
  - medium_complexity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Import RedHat GPG key
  rpm_key:
    state: present
    key: /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
  when:
  - gpg_key_directory_permission.stat.mode <= '0755'
  - (gpg_installed_fingerprints | difference(gpg_valid_fingerprints)) | length ==
    0
  - gpg_installed_fingerprints | length > 0
  - ansible_distribution == "RedHat"
  tags:
  - CJIS-5.10.4.1
  - NIST-800-171-3.4.8
  - NIST-800-53-CM-5(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SI-7
  - PCI-DSS-Req-6.2
  - PCI-DSSv4-6.3
  - PCI-DSSv4-6.3.3
  - ensure_redhat_gpgkey_installed
  - high_severity
  - medium_complexity
  - medium_disruption
  - no_reboot_needed
  - restrict_strategy

Rule Ensure Software Patches Installed [ref]

NOTE: U.S. Defense systems are required to be patched within 30 days or sooner as local policy dictates.

Warning: Red Hat Virtualization 4 does not have a corresponding OVAL CVE Feed. Therefore, this will result in a "not checked" result during a scan.

Rationale:

Installing software updates is a fundamental mitigation against the exploitation of publicly-known vulnerabilities. If the most recent security patches and updates are not installed, unauthorized users may take advantage of weaknesses in the unpatched software. The lack of prompt attention to patching could result in a system compromise.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_security_patches_up_to_date

References:

cis-csc	18, 20, 4
cjis	5.10.4.1
cobit5	APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02
disa	CCI-000366
isa-62443-2009	4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9
iso27001-2013	A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3
nist	SI-2(5), SI-2(c), CM-6(a)
nist-csf	ID.RA-1, PR.IP-12
ospp	FMT_MOF_EXT.1
pcidss	Req-6.2
os-srg	SRG-OS-000480-GPOS-00227
anssi	R61
pcidss4	6.3.3, 6.3

Group Account and Access Control Group contains 17 groups and 66 rules

[ref] In traditional Unix security, if an attacker gains shell access to a certain login account, they can perform any action or access any file to which that account has access. Therefore, making it more difficult for unauthorized people to gain shell access to accounts, particularly to privileged accounts, is a necessary part of securing a system. This section introduces mechanisms for restricting access to accounts under Red Hat Virtualization 4.

Group Warning Banners for System Accesses Group contains 1 rule

[ref] Each system should expose as little information about itself as possible.

System banners, which are typically displayed just before a login prompt, give out information about the service or the host's operating system. This might include the distribution name and the system kernel version, and the particular version of a network service. This information can assist intruders in gaining access to the system as it can reveal whether the system is running vulnerable software. Most network services can be configured to limit what information is displayed.

Many organizations implement security policies that require a system banner provide notice of the system's ownership, provide warning to unauthorized users, and remind authorized users of their consent to monitoring.

Rule Modify the System Login Banner [ref]

To configure the system login banner edit /etc/issue. Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is either:

You are accessing a U.S. Government (USG) Information System (IS) that
is provided for USG-authorized use only. By using this IS (which includes
any device attached to this IS), you consent to the following conditions:

-The USG routinely intercepts and monitors communications on this IS
for purposes including, but not limited to, penetration testing, COMSEC
monitoring, network operations and defense, personnel misconduct (PM), law
enforcement (LE), and counterintelligence (CI) investigations.

-At any time, the USG may inspect and seize data stored on this IS.

-Communications using, or data stored on, this IS are not private,
are subject to routine monitoring, interception, and search, and may be
disclosed or used for any USG-authorized purpose.

-This IS includes security measures (e.g., authentication and access
controls) to protect USG interests -- not for your personal benefit or
privacy.

-Notwithstanding the above, using this IS does not constitute consent
to PM, LE or CI investigative searching or monitoring of the content of
privileged communications, or work product, related to personal
representation or services by attorneys, psychotherapists, or clergy, and
their assistants. Such communications and work product are private and
confidential. See User Agreement for details.

OR:

I've read & consent to terms in IS user agreem't.

Rationale:

Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.

System use notifications are required only for access via login interfaces with human users and are not required when such human interfaces do not exist.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_banner_etc_issue

References:

cis-csc	1, 12, 15, 16
cobit5	DSS05.04, DSS05.10, DSS06.10
cui	3.1.9
disa	CCI-001387, CCI-001384, CCI-000048, CCI-001386, CCI-001388, CCI-001385
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nist	AC-8(a), AC-8(c)
nist-csf	PR.AC-7
os-srg	SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

login_banner_text='^(You[\s\n]+are[\s\n]+accessing[\s\n]+a[\s\n]+U\.S\.[\s\n]+Government[\s\n]+\(USG\)[\s\n]+Information[\s\n]+System[\s\n]+\(IS\)[\s\n]+that[\s\n]+is[\s\n]+provided[\s\n]+for[\s\n]+USG\-authorized[\s\n]+use[\s\n]+only\.[\s\n]+By[\s\n]+using[\s\n]+this[\s\n]+IS[\s\n]+\(which[\s\n]+includes[\s\n]+any[\s\n]+device[\s\n]+attached[\s\n]+to[\s\n]+this[\s\n]+IS\),[\s\n]+you[\s\n]+consent[\s\n]+to[\s\n]+the[\s\n]+following[\s\n]+conditions\:(?:[\n]+|(?:\\n)+)\-The[\s\n]+USG[\s\n]+routinely[\s\n]+intercepts[\s\n]+and[\s\n]+monitors[\s\n]+communications[\s\n]+on[\s\n]+this[\s\n]+IS[\s\n]+for[\s\n]+purposes[\s\n]+including,[\s\n]+but[\s\n]+not[\s\n]+limited[\s\n]+to,[\s\n]+penetration[\s\n]+testing,[\s\n]+COMSEC[\s\n]+monitoring,[\s\n]+network[\s\n]+operations[\s\n]+and[\s\n]+defense,[\s\n]+personnel[\s\n]+misconduct[\s\n]+\(PM\),[\s\n]+law[\s\n]+enforcement[\s\n]+\(LE\),[\s\n]+and[\s\n]+counterintelligence[\s\n]+\(CI\)[\s\n]+investigations\.(?:[\n]+|(?:\\n)+)\-At[\s\n]+any[\s\n]+time,[\s\n]+the[\s\n]+USG[\s\n]+may[\s\n]+inspect[\s\n]+and[\s\n]+seize[\s\n]+data[\s\n]+stored[\s\n]+on[\s\n]+this[\s\n]+IS\.(?:[\n]+|(?:\\n)+)\-Communications[\s\n]+using,[\s\n]+or[\s\n]+data[\s\n]+stored[\s\n]+on,[\s\n]+this[\s\n]+IS[\s\n]+are[\s\n]+not[\s\n]+private,[\s\n]+are[\s\n]+subject[\s\n]+to[\s\n]+routine[\s\n]+monitoring,[\s\n]+interception,[\s\n]+and[\s\n]+search,[\s\n]+and[\s\n]+may[\s\n]+be[\s\n]+disclosed[\s\n]+or[\s\n]+used[\s\n]+for[\s\n]+any[\s\n]+USG\-authorized[\s\n]+purpose\.(?:[\n]+|(?:\\n)+)\-This[\s\n]+IS[\s\n]+includes[\s\n]+security[\s\n]+measures[\s\n]+\(e\.g\.,[\s\n]+authentication[\s\n]+and[\s\n]+access[\s\n]+controls\)[\s\n]+to[\s\n]+protect[\s\n]+USG[\s\n]+interests\-\-not[\s\n]+for[\s\n]+your[\s\n]+personal[\s\n]+benefit[\s\n]+or[\s\n]+privacy\.(?:[\n]+|(?:\\n)+)\-Notwithstanding[\s\n]+the[\s\n]+above,[\s\n]+using[\s\n]+this[\s\n]+IS[\s\n]+does[\s\n]+not[\s\n]+constitute[\s\n]+consent[\s\n]+to[\s\n]+PM,[\s\n]+LE[\s\n]+or[\s\n]+CI[\s\n]+investigative[\s\n]+searching[\s\n]+or[\s\n]+monitoring[\s\n]+of[\s\n]+the[\s\n]+content[\s\n]+of[\s\n]+privileged[\s\n]+communications,[\s\n]+or[\s\n]+work[\s\n]+product,[\s\n]+related[\s\n]+to[\s\n]+personal[\s\n]+representation[\s\n]+or[\s\n]+services[\s\n]+by[\s\n]+attorneys,[\s\n]+psychotherapists,[\s\n]+or[\s\n]+clergy,[\s\n]+and[\s\n]+their[\s\n]+assistants\.[\s\n]+Such[\s\n]+communications[\s\n]+and[\s\n]+work[\s\n]+product[\s\n]+are[\s\n]+private[\s\n]+and[\s\n]+confidential\.[\s\n]+See[\s\n]+User[\s\n]+Agreement[\s\n]+for[\s\n]+details\.|I've[\s\n]+read[\s\n]+\&[\s\n]+consent[\s\n]+to[\s\n]+terms[\s\n]+in[\s\n]+IS[\s\n]+user[\s\n]+agreem't\.)$'


# Multiple regexes transform the banner regex into a usable banner
# 0 - Remove anchors around the banner text
login_banner_text=$(echo "$login_banner_text" | sed 's/^\^\(.*\)\$$/\1/g')
# 1 - Keep only the first banners if there are multiple
#    (dod_banners contains the long and short banner)
login_banner_text=$(echo "$login_banner_text" | sed 's/^(\(.*\.\)|.*)$/\1/g')
# 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
login_banner_text=$(echo "$login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
# 3 - Adds newlines. (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "\n")
login_banner_text=$(echo "$login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\\\n)+)/\n/g')
# 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
login_banner_text=$(echo "$login_banner_text" | sed 's/\\//g')
formatted=$(echo "$login_banner_text" | fold -sw 80)
cat <<EOF >/etc/issue
$formatted
EOF

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Group Protect Accounts by Configuring PAM Group contains 4 groups and 20 rules

[ref] PAM, or Pluggable Authentication Modules, is a system which implements modular authentication for Linux programs. PAM provides a flexible and configurable architecture for authentication, and it should be configured to minimize exposure to unnecessary risk. This section contains guidance on how to accomplish that.

PAM is implemented as a set of shared objects which are loaded and invoked whenever an application wishes to authenticate a user. Typically, the application must be running as root in order to take advantage of PAM, because PAM's modules often need to be able to access sensitive stores of account information, such as /etc/shadow. Traditional privileged network listeners (e.g. sshd) or SUID programs (e.g. sudo) already meet this requirement. An SUID root application, userhelper, is provided so that programs which are not SUID or privileged themselves can still take advantage of PAM.

PAM looks in the directory /etc/pam.d for application-specific configuration information. For instance, if the program login attempts to authenticate a user, then PAM's libraries follow the instructions in the file /etc/pam.d/login to determine what actions should be taken.

One very important file in /etc/pam.d is /etc/pam.d/system-auth. This file, which is included by many other PAM configuration files, defines 'default' system authentication measures. Modifying this file is a good way to make far-reaching authentication changes, for instance when implementing a centralized authentication service.

Warning: Be careful when making changes to PAM's configuration files. The syntax for these files is complex, and modifications can have unexpected consequences. The default configurations shipped with applications should be sufficient for most users.

Warning: Running authconfig or system-config-authentication will re-write the PAM configuration files, destroying any manually made changes and replacing them with a series of system defaults. One reference to the configuration file syntax can be found at https://fossies.org/linux/Linux-PAM-docs/doc/sag/Linux-PAM_SAG.pdf.

Group Set Lockouts for Failed Password Attempts Group contains 5 rules

[ref] The pam_faillock PAM module provides the capability to lock out user accounts after a number of failed login attempts. Its documentation is available in /usr/share/doc/pam-VERSION/txts/README.pam_faillock.

Warning: Locking out user accounts presents the risk of a denial-of-service attack. The lockout policy must weigh whether the risk of such a denial-of-service attack outweighs the benefits of thwarting password guessing attacks.

Rule Limit Password Reuse [ref]

Do not allow users to reuse recent passwords. This can be accomplished by using the remember option for the pam_unix or pam_pwhistory PAM modules.

Warning: Newer versions of authselect contain an authselect feature to easily and properly enable pam_pwhistory.so module. If this feature is not yet available in your system, an authselect custom profile must be used to avoid integrity issues in PAM files.

Rationale:

Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_unix_remember

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.1.1
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.5.8
disa	CCI-000200
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(f), IA-5(1)(e)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.2.5
os-srg	SRG-OS-000077-GPOS-00045
anssi	R31
pcidss4	8.3.7, 8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_unix_remember='5'






if [ -f /usr/bin/authselect ]; then
    if authselect list-features sssd | grep -q with-pwhistory; then
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi
        authselect enable-feature with-pwhistory

        authselect apply-changes -b
    else
        
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi

        CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
        # If not already in use, a custom profile is created preserving the enabled features.
        if [[ ! $CURRENT_PROFILE == custom/* ]]; then
            ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
            authselect create-profile hardening -b $CURRENT_PROFILE
            CURRENT_PROFILE="custom/hardening"
            
            authselect apply-changes -b --backup=before-hardening-custom-profile
            authselect select $CURRENT_PROFILE
            for feature in $ENABLED_FEATURES; do
                authselect enable-feature $feature;
            done
            
            authselect apply-changes -b --backup=after-hardening-custom-profile
        fi
        PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
        PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

        authselect apply-changes -b
        
        if ! grep -qP "^\s*password\s+requisite\s+pam_pwhistory.so\s*.*" "$PAM_FILE_PATH"; then
            # Line matching group + control + module was not found. Check group + module.
            if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                # The control is updated only if one single line matches.
                sed -i -E --follow-symlinks "s/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1requisite \2/" "$PAM_FILE_PATH"
            else
                LAST_MATCH_LINE=$(grep -nP "^password.*requisite.*pam_pwquality\.so" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
                if [ ! -z $LAST_MATCH_LINE ]; then
                    sed -i --follow-symlinks $LAST_MATCH_LINE" a password     requisite    pam_pwhistory.so" "$PAM_FILE_PATH"
                else
                    echo "password    requisite    pam_pwhistory.so" >> "$PAM_FILE_PATH"
                fi
            fi
        fi
    fi
else

    
    if ! grep -qP "^\s*password\s+requisite\s+pam_pwhistory.so\s*.*" "/etc/pam.d/system-auth"; then
        # Line matching group + control + module was not found. Check group + module.
        if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "/etc/pam.d/system-auth")" -eq 1 ]; then
            # The control is updated only if one single line matches.
            sed -i -E --follow-symlinks "s/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1requisite \2/" "/etc/pam.d/system-auth"
        else
            LAST_MATCH_LINE=$(grep -nP "^password.*requisite.*pam_pwquality\.so" "/etc/pam.d/system-auth" | tail -n 1 | cut -d: -f 1)
            if [ ! -z $LAST_MATCH_LINE ]; then
                sed -i --follow-symlinks $LAST_MATCH_LINE" a password     requisite    pam_pwhistory.so" "/etc/pam.d/system-auth"
            else
                echo "password    requisite    pam_pwhistory.so" >> "/etc/pam.d/system-auth"
            fi
        fi
    fi

fi

PWHISTORY_CONF="/etc/security/pwhistory.conf"
if [ -f $PWHISTORY_CONF ]; then
    regex="^\s*remember\s*="
    line="remember = $var_password_pam_unix_remember"
    if ! grep -q $regex $PWHISTORY_CONF; then
        echo $line >> $PWHISTORY_CONF
    else
        sed -i --follow-symlinks 's|^\s*\(remember\s*=\s*\)\(\S\+\)|\1'"$var_password_pam_unix_remember"'|g' $PWHISTORY_CONF
    fi
    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then
            
            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"
                
                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done
                
                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi
        
    if grep -qP "^\s*password\s.*\bpam_pwhistory.so\s.*\bremember\b" "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks "s/(.*password.*pam_pwhistory.so.*)\bremember\b=?[[:alnum:]]*(.*)/\1\2/g" "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then
            
            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi
else
    PAM_FILE_PATH="/etc/pam.d/system-auth"
    if [ -f /usr/bin/authselect ]; then
        
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi

        CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
        # If not already in use, a custom profile is created preserving the enabled features.
        if [[ ! $CURRENT_PROFILE == custom/* ]]; then
            ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
            authselect create-profile hardening -b $CURRENT_PROFILE
            CURRENT_PROFILE="custom/hardening"
            
            authselect apply-changes -b --backup=before-hardening-custom-profile
            authselect select $CURRENT_PROFILE
            for feature in $ENABLED_FEATURES; do
                authselect enable-feature $feature;
            done
            
            authselect apply-changes -b --backup=after-hardening-custom-profile
        fi
        PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
        PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

        authselect apply-changes -b
    fi
    

    if ! grep -qP "^\s*password\s+requisite\s+pam_pwhistory.so\s*.*" "$PAM_FILE_PATH"; then
        # Line matching group + control + module was not found. Check group + module.
        if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
            # The control is updated only if one single line matches.
            sed -i -E --follow-symlinks "s/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1requisite \2/" "$PAM_FILE_PATH"
        else
            echo "password    requisite    pam_pwhistory.so" >> "$PAM_FILE_PATH"
        fi
    fi
    # Check the option
    if ! grep -qP "^\s*password\s+requisite\s+pam_pwhistory.so\s*.*\sremember\b" "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks "/\s*password\s+requisite\s+pam_pwhistory.so.*/ s/$/ remember=$var_password_pam_unix_remember/" "$PAM_FILE_PATH"
    else
        sed -i -E --follow-symlinks "s/(\s*password\s+requisite\s+pam_pwhistory.so\s+.*)(remember=)[[:alnum:]]+\s*(.*)/\1\2$var_password_pam_unix_remember \3/" "$PAM_FILE_PATH"
    fi
    if [ -f /usr/bin/authselect ]; then
        
        authselect apply-changes -b
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-IA-5(1)(e)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.5
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.7
  - accounts_password_pam_unix_remember
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value var_password_pam_unix_remember # promote to variable
  set_fact:
    var_password_pam_unix_remember: !!str 5
  tags:
    - always

- name: Limit Password Reuse - Check if system relies on authselect tool
  ansible.builtin.stat:
    path: /usr/bin/authselect
  register: result_authselect_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-IA-5(1)(e)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.5
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.7
  - accounts_password_pam_unix_remember
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Limit Password Reuse - Collect the available authselect features
  ansible.builtin.command:
    cmd: authselect list-features sssd
  register: result_authselect_available_features
  changed_when: false
  when:
  - '"pam" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-IA-5(1)(e)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.5
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.7
  - accounts_password_pam_unix_remember
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Limit Password Reuse - Enable pam_pwhistory.so using authselect feature
  block:

  - name: Limit Password Reuse - Check integrity of authselect current profile
    ansible.builtin.command:
      cmd: authselect check
    register: result_authselect_check_cmd
    changed_when: false
    failed_when: false

  - name: Limit Password Reuse - Informative message based on the authselect integrity
      check result
    ansible.builtin.assert:
      that:
      - result_authselect_check_cmd.rc == 0
      fail_msg:
      - authselect integrity check failed. Remediation aborted!
      - This remediation could not be applied because an authselect profile was not
        selected or the selected profile is not intact.
      - It is not recommended to manually edit the PAM files when authselect tool
        is available.
      - In cases where the default authselect profile does not cover a specific demand,
        a custom authselect profile is recommended.
      success_msg:
      - authselect integrity check passed

  - name: Limit Password Reuse - Get authselect current features
    ansible.builtin.shell:
      cmd: authselect current | tail -n+3 | awk '{ print $2 }'
    register: result_authselect_features
    changed_when: false
    when:
    - result_authselect_check_cmd is success

  - name: Limit Password Reuse - Ensure "with-pwhistory" feature is enabled using
      authselect tool
    ansible.builtin.command:
      cmd: authselect enable-feature with-pwhistory
    register: result_authselect_enable_feature_cmd
    when:
    - result_authselect_check_cmd is success
    - result_authselect_features.stdout is not search("with-pwhistory")

  - name: Limit Password Reuse - Ensure authselect changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_enable_feature_cmd is not skipped
    - result_authselect_enable_feature_cmd is success
  when:
  - '"pam" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  - result_authselect_available_features.stdout is search("with-pwhistory")
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-IA-5(1)(e)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.5
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.7
  - accounts_password_pam_unix_remember
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Limit Password Reuse - Enable pam_pwhistory.so in appropriate PAM files
  block:

  - name: Limit Password Reuse - Define the PAM file to be edited as a local fact
    ansible.builtin.set_fact:
      pam_file_path: /etc/pam.d/system-auth

  - name: Limit Password Reuse - Check if system relies on authselect tool
    ansible.builtin.stat:
      path: /usr/bin/authselect
    register: result_authselect_present

  - name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
      is present
    block:

    - name: Limit Password Reuse - Check integrity of authselect current profile
      ansible.builtin.command:
        cmd: authselect check
      register: result_authselect_check_cmd
      changed_when: false
      failed_when: false

    - name: Limit Password Reuse - Informative message based on the authselect integrity
        check result
      ansible.builtin.assert:
        that:
        - result_authselect_check_cmd.rc == 0
        fail_msg:
        - authselect integrity check failed. Remediation aborted!
        - This remediation could not be applied because an authselect profile was
          not selected or the selected profile is not intact.
        - It is not recommended to manually edit the PAM files when authselect tool
          is available.
        - In cases where the default authselect profile does not cover a specific
          demand, a custom authselect profile is recommended.
        success_msg:
        - authselect integrity check passed

    - name: Limit Password Reuse - Get authselect current profile
      ansible.builtin.shell:
        cmd: authselect current -r | awk '{ print $1 }'
      register: result_authselect_profile
      changed_when: false
      when:
      - result_authselect_check_cmd is success

    - name: Limit Password Reuse - Define the current authselect profile as a local
        fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is match("custom/")

    - name: Limit Password Reuse - Define the new authselect custom profile as a local
        fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: custom/hardening
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is not match("custom/")

    - name: Limit Password Reuse - Get authselect current features to also enable
        them in the custom profile
      ansible.builtin.shell:
        cmd: authselect current | tail -n+3 | awk '{ print $2 }'
      register: result_authselect_features
      changed_when: false
      when:
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")

    - name: Limit Password Reuse - Check if any custom profile with the same name
        was already created
      ansible.builtin.stat:
        path: /etc/authselect/{{ authselect_custom_profile }}
      register: result_authselect_custom_profile_present
      changed_when: false
      when:
      - authselect_current_profile is not match("custom/")

    - name: Limit Password Reuse - Create an authselect custom profile based on the
        current profile
      ansible.builtin.command:
        cmd: authselect create-profile hardening -b {{ authselect_current_profile
          }}
      when:
      - result_authselect_check_cmd is success
      - authselect_current_profile is not match("custom/")
      - not result_authselect_custom_profile_present.stat.exists

    - name: Limit Password Reuse - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Limit Password Reuse - Ensure the authselect custom profile is selected
      ansible.builtin.command:
        cmd: authselect select {{ authselect_custom_profile }}
      register: result_pam_authselect_select_profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Limit Password Reuse - Restore the authselect features in the custom profile
      ansible.builtin.command:
        cmd: authselect enable-feature {{ item }}
      loop: '{{ result_authselect_features.stdout_lines }}'
      register: result_pam_authselect_restore_features
      when:
      - result_authselect_profile is not skipped
      - result_authselect_features is not skipped
      - result_pam_authselect_select_profile is not skipped

    - name: Limit Password Reuse - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - result_pam_authselect_restore_features is not skipped

    - name: Limit Password Reuse - Change the PAM file to be edited according to the
        custom authselect profile
      ansible.builtin.set_fact:
        pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
          | basename }}
    when:
    - result_authselect_present.stat.exists

  - name: Limit Password Reuse - Define a fact for control already filtered in case
      filters are used
    ansible.builtin.set_fact:
      pam_module_control: requisite

  - name: Limit Password Reuse - Check if expected PAM module line is present in {{
      pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      regexp: ^\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_pwhistory.so\s*.*
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_line_present

  - name: Limit Password Reuse - Include or update the PAM module line in {{ pam_file_path
      }}
    block:

    - name: Limit Password Reuse - Check if required PAM module line is present in
        {{ pam_file_path }} with different control
      ansible.builtin.lineinfile:
        path: '{{ pam_file_path }}'
        regexp: ^\s*password\s+.*\s+pam_pwhistory.so\s*
        state: absent
      check_mode: true
      changed_when: false
      register: result_pam_line_other_control_present

    - name: Limit Password Reuse - Ensure the correct control for the required PAM
        module line in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: ^(\s*password\s+).*(\bpam_pwhistory.so.*)
        replace: \1{{ pam_module_control }} \2
      register: result_pam_module_edit
      when:
      - result_pam_line_other_control_present.found == 1

    - name: Limit Password Reuse - Ensure the required PAM module line is included
        in {{ pam_file_path }}
      ansible.builtin.lineinfile:
        dest: '{{ pam_file_path }}'
        insertafter: ^password.*requisite.*pam_pwquality\.so
        line: password    {{ pam_module_control }}    pam_pwhistory.so
      register: result_pam_module_add
      when:
      - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
        > 1

    - name: Limit Password Reuse - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present is defined
      - result_authselect_present.stat.exists
      - |-
        (result_pam_module_add is defined and result_pam_module_add.changed)
         or (result_pam_module_edit is defined and result_pam_module_edit.changed)
    when:
    - result_pam_line_present.found is defined
    - result_pam_line_present.found == 0
  when:
  - '"pam" in ansible_facts.packages'
  - |
    (result_authselect_available_features.stdout is defined and result_authselect_available_features.stdout is not search("with-pwhistory")) or result_authselect_available_features is not defined
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-IA-5(1)(e)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.5
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.7
  - accounts_password_pam_unix_remember
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Limit Password Reuse - Check the presence of /etc/security/pwhistory.conf
    file
  ansible.builtin.stat:
    path: /etc/security/pwhistory.conf
  register: result_pwhistory_conf_check
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-IA-5(1)(e)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.5
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.7
  - accounts_password_pam_unix_remember
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Limit Password Reuse - pam_pwhistory.so parameters are configured in /etc/security/pwhistory.conf
    file
  block:

  - name: Limit Password Reuse - Ensure the pam_pwhistory.so remember parameter in
      /etc/security/pwhistory.conf
    ansible.builtin.lineinfile:
      path: /etc/security/pwhistory.conf
      regexp: ^\s*remember\s*=
      line: remember = {{ var_password_pam_unix_remember }}
      state: present

  - name: Limit Password Reuse - Ensure the pam_pwhistory.so remember parameter is
      removed from PAM files
    block:

    - name: Limit Password Reuse - Check if /etc/pam.d/system-auth file is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present

    - name: Limit Password Reuse - Check the proper remediation for the system
      block:

      - name: Limit Password Reuse - Define the PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Limit Password Reuse - Check if system relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
          is present
        block:

        - name: Limit Password Reuse - Check integrity of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Limit Password Reuse - Informative message based on the authselect
            integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile
              was not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect
              tool is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Limit Password Reuse - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Limit Password Reuse - Define the current authselect profile as a
            local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Limit Password Reuse - Define the new authselect custom profile as
            a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Limit Password Reuse - Get authselect current features to also enable
            them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Limit Password Reuse - Check if any custom profile with the same name
            was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Limit Password Reuse - Create an authselect custom profile based on
            the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Limit Password Reuse - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Limit Password Reuse - Ensure the authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Limit Password Reuse - Restore the authselect features in the custom
            profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Limit Password Reuse - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Limit Password Reuse - Change the PAM file to be edited according
            to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Limit Password Reuse - Define a fact for control already filtered in
          case filters are used
        ansible.builtin.set_fact:
          pam_module_control: ''

      - name: Limit Password Reuse - Ensure the "remember" option from "pam_pwhistory.so"
          is not present in {{ pam_file_path }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwhistory.so.*)\bremember\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Limit Password Reuse - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - result_pam_file_present.stat.exists
  when:
  - '"pam" in ansible_facts.packages'
  - result_pwhistory_conf_check.stat.exists
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-IA-5(1)(e)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.5
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.7
  - accounts_password_pam_unix_remember
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Limit Password Reuse - pam_pwhistory.so parameters are configured in PAM files
  block:

  - name: Limit Password Reuse - Define the PAM file to be edited as a local fact
    ansible.builtin.set_fact:
      pam_file_path: /etc/pam.d/system-auth

  - name: Limit Password Reuse - Check if system relies on authselect tool
    ansible.builtin.stat:
      path: /usr/bin/authselect
    register: result_authselect_present

  - name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
      is present
    block:

    - name: Limit Password Reuse - Check integrity of authselect current profile
      ansible.builtin.command:
        cmd: authselect check
      register: result_authselect_check_cmd
      changed_when: false
      failed_when: false

    - name: Limit Password Reuse - Informative message based on the authselect integrity
        check result
      ansible.builtin.assert:
        that:
        - result_authselect_check_cmd.rc == 0
        fail_msg:
        - authselect integrity check failed. Remediation aborted!
        - This remediation could not be applied because an authselect profile was
          not selected or the selected profile is not intact.
        - It is not recommended to manually edit the PAM files when authselect tool
          is available.
        - In cases where the default authselect profile does not cover a specific
          demand, a custom authselect profile is recommended.
        success_msg:
        - authselect integrity check passed

    - name: Limit Password Reuse - Get authselect current profile
      ansible.builtin.shell:
        cmd: authselect current -r | awk '{ print $1 }'
      register: result_authselect_profile
      changed_when: false
      when:
      - result_authselect_check_cmd is success

    - name: Limit Password Reuse - Define the current authselect profile as a local
        fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is match("custom/")

    - name: Limit Password Reuse - Define the new authselect custom profile as a local
        fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: custom/hardening
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is not match("custom/")

    - name: Limit Password Reuse - Get authselect current features to also enable
        them in the custom profile
      ansible.builtin.shell:
        cmd: authselect current | tail -n+3 | awk '{ print $2 }'
      register: result_authselect_features
      changed_when: false
      when:
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")

    - name: Limit Password Reuse - Check if any custom profile with the same name
        was already created
      ansible.builtin.stat:
        path: /etc/authselect/{{ authselect_custom_profile }}
      register: result_authselect_custom_profile_present
      changed_when: false
      when:
      - authselect_current_profile is not match("custom/")

    - name: Limit Password Reuse - Create an authselect custom profile based on the
        current profile
      ansible.builtin.command:
        cmd: authselect create-profile hardening -b {{ authselect_current_profile
          }}
      when:
      - result_authselect_check_cmd is success
      - authselect_current_profile is not match("custom/")
      - not result_authselect_custom_profile_present.stat.exists

    - name: Limit Password Reuse - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Limit Password Reuse - Ensure the authselect custom profile is selected
      ansible.builtin.command:
        cmd: authselect select {{ authselect_custom_profile }}
      register: result_pam_authselect_select_profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Limit Password Reuse - Restore the authselect features in the custom profile
      ansible.builtin.command:
        cmd: authselect enable-feature {{ item }}
      loop: '{{ result_authselect_features.stdout_lines }}'
      register: result_pam_authselect_restore_features
      when:
      - result_authselect_profile is not skipped
      - result_authselect_features is not skipped
      - result_pam_authselect_select_profile is not skipped

    - name: Limit Password Reuse - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - result_pam_authselect_restore_features is not skipped

    - name: Limit Password Reuse - Change the PAM file to be edited according to the
        custom authselect profile
      ansible.builtin.set_fact:
        pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
          | basename }}
    when:
    - result_authselect_present.stat.exists

  - name: Limit Password Reuse - Define a fact for control already filtered in case
      filters are used
    ansible.builtin.set_fact:
      pam_module_control: requisite

  - name: Limit Password Reuse - Check if expected PAM module line is present in {{
      pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      regexp: ^\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_pwhistory.so\s*.*
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_line_present

  - name: Limit Password Reuse - Include or update the PAM module line in {{ pam_file_path
      }}
    block:

    - name: Limit Password Reuse - Check if required PAM module line is present in
        {{ pam_file_path }} with different control
      ansible.builtin.lineinfile:
        path: '{{ pam_file_path }}'
        regexp: ^\s*password\s+.*\s+pam_pwhistory.so\s*
        state: absent
      check_mode: true
      changed_when: false
      register: result_pam_line_other_control_present

    - name: Limit Password Reuse - Ensure the correct control for the required PAM
        module line in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: ^(\s*password\s+).*(\bpam_pwhistory.so.*)
        replace: \1{{ pam_module_control }} \2
      register: result_pam_module_edit
      when:
      - result_pam_line_other_control_present.found == 1

    - name: Limit Password Reuse - Ensure the required PAM module line is included
        in {{ pam_file_path }}
      ansible.builtin.lineinfile:
        dest: '{{ pam_file_path }}'
        line: password    {{ pam_module_control }}    pam_pwhistory.so
      register: result_pam_module_add
      when:
      - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
        > 1

    - name: Limit Password Reuse - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present is defined
      - result_authselect_present.stat.exists
      - |-
        (result_pam_module_add is defined and result_pam_module_add.changed)
         or (result_pam_module_edit is defined and result_pam_module_edit.changed)
    when:
    - result_pam_line_present.found is defined
    - result_pam_line_present.found == 0

  - name: Limit Password Reuse - Define a fact for control already filtered in case
      filters are used
    ansible.builtin.set_fact:
      pam_module_control: requisite

  - name: Limit Password Reuse - Check if the required PAM module option is present
      in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      regexp: ^\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_pwhistory.so\s*.*\sremember\b
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_module_accounts_password_pam_unix_remember_option_present

  - name: Limit Password Reuse - Ensure the "remember" PAM option for "pam_pwhistory.so"
      is included in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      backrefs: true
      regexp: ^(\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_pwhistory.so.*)
      line: \1 remember={{ var_password_pam_unix_remember }}
      state: present
    register: result_pam_accounts_password_pam_unix_remember_add
    when:
    - result_pam_module_accounts_password_pam_unix_remember_option_present.found ==
      0

  - name: Limit Password Reuse - Ensure the required value for "remember" PAM option
      from "pam_pwhistory.so" in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      backrefs: true
      regexp: ^(\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_pwhistory.so\s+.*)(remember)=[0-9a-zA-Z]+\s*(.*)
      line: \1\2={{ var_password_pam_unix_remember }} \3
    register: result_pam_accounts_password_pam_unix_remember_edit
    when:
    - result_pam_module_accounts_password_pam_unix_remember_option_present.found >
      0

  - name: Limit Password Reuse - Ensure authselect changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_present.stat.exists
    - (result_pam_remember_add is defined and result_pam_remember_add.changed) or
      (result_pam_remember_edit is defined and result_pam_remember_edit.changed)
  when:
  - '"pam" in ansible_facts.packages'
  - not result_pwhistory_conf_check.stat.exists
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-IA-5(1)(e)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.5
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.7
  - accounts_password_pam_unix_remember
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

Rule Lock Accounts After Failed Password Attempts [ref]

This rule configures the system to lock out accounts after a number of incorrect login attempts using pam_faillock.so. pam_faillock.so module requires multiple entries in pam files. These entries must be carefully defined to work as expected. Ensure that the file /etc/security/faillock.conf contains the following entry: deny = <count> Where count should be less than or equal to 3 and greater than 0. In order to avoid errors when manually editing these files, it is recommended to use the appropriate tools, such as authselect or authconfig, depending on the OS version.

Warning: If the system relies on authselect tool to manage PAM settings, the remediation will also use authselect tool. However, if any manual modification was made in PAM files, the authselect integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report. If the system supports the /etc/security/faillock.conf file, the pam_faillock parameters should be defined in faillock.conf file.

Rationale:

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking the account.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_deny

References:

cis-csc	1, 12, 15, 16
cjis	5.5.3
cobit5	DSS05.04, DSS05.10, DSS06.10
cui	3.1.8
disa	CCI-000044, CCI-002238
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-6(a), AC-7(a)
nist-csf	PR.AC-7
ospp	FIA_AFL.1
pcidss	Req-8.1.6
os-srg	SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005
anssi	R31
pcidss4	8.3.4, 8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_accounts_passwords_pam_faillock_deny='3'


if [ -f /usr/bin/authselect ]; then
    if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
authselect enable-feature with-faillock

authselect apply-changes -b
else
    
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
    if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
        sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix\.so.*/i auth        required      pam_faillock.so preauth silent' "$pam_file"
        sed -i --follow-symlinks '/^auth.*required.*pam_deny\.so.*/i auth        required      pam_faillock.so authfail' "$pam_file"
        sed -i --follow-symlinks '/^account.*required.*pam_unix\.so.*/i account     required      pam_faillock.so' "$pam_file"
    fi
    sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock\.so)/\1required     \3/g' "$pam_file"
done

fi

AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
SKIP_FAILLOCK_CHECK=false

FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ] || [ "$SKIP_FAILLOCK_CHECK" = "true" ]; then
    regex="^\s*deny\s*="
    line="deny = $var_accounts_passwords_pam_faillock_deny"
    if ! grep -q $regex $FAILLOCK_CONF; then
        echo $line >> $FAILLOCK_CONF
    else
        sed -i --follow-symlinks 's|^\s*\(deny\s*=\s*\)\(\S\+\)|\1'"$var_accounts_passwords_pam_faillock_deny"'|g' $FAILLOCK_CONF
    fi
    
    for pam_file in "${AUTH_FILES[@]}"
    do
        if [ -e "$pam_file" ] ; then
            PAM_FILE_PATH="$pam_file"
            if [ -f /usr/bin/authselect ]; then
                
                if ! authselect check; then
                echo "
                authselect integrity check failed. Remediation aborted!
                This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                It is not recommended to manually edit the PAM files when authselect tool is available.
                In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                exit 1
                fi

                CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                # If not already in use, a custom profile is created preserving the enabled features.
                if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                    ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                    authselect create-profile hardening -b $CURRENT_PROFILE
                    CURRENT_PROFILE="custom/hardening"
                    
                    authselect apply-changes -b --backup=before-hardening-custom-profile
                    authselect select $CURRENT_PROFILE
                    for feature in $ENABLED_FEATURES; do
                        authselect enable-feature $feature;
                    done
                    
                    authselect apply-changes -b --backup=after-hardening-custom-profile
                fi
                PAM_FILE_NAME=$(basename "$pam_file")
                PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                authselect apply-changes -b
            fi
            
        if grep -qP "^\s*auth\s.*\bpam_faillock.so\s.*\bdeny\b" "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks "s/(.*auth.*pam_faillock.so.*)\bdeny\b=?[[:alnum:]]*(.*)/\1\2/g" "$PAM_FILE_PATH"
        fi
            if [ -f /usr/bin/authselect ]; then
                
                authselect apply-changes -b
            fi
        else
            echo "$pam_file was not found" >&2
        fi
    done
    
else
    for pam_file in "${AUTH_FILES[@]}"
    do
        if ! grep -qE '^\s*auth.*pam_faillock\.so (preauth|authfail).*deny' "$pam_file"; then
            sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*preauth.*silent.*/ s/$/ deny='"$var_accounts_passwords_pam_faillock_deny"'/' "$pam_file"
            sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*authfail.*/ s/$/ deny='"$var_accounts_passwords_pam_faillock_deny"'/' "$pam_file"
        else
            sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*preauth.*silent.*\)\('"deny"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_deny"'\3/' "$pam_file"
            sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*authfail.*\)\('"deny"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_deny"'\3/' "$pam_file"
        fi
    done
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Lock Accounts After Failed Password Attempts - Check if system relies on authselect
    tool
  ansible.builtin.stat:
    path: /usr/bin/authselect
  register: result_authselect_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Lock Accounts After Failed Password Attempts - Remediation where authselect
    tool is present
  block:

  - name: Lock Accounts After Failed Password Attempts - Check integrity of authselect
      current profile
    ansible.builtin.command:
      cmd: authselect check
    register: result_authselect_check_cmd
    changed_when: false
    failed_when: false

  - name: Lock Accounts After Failed Password Attempts - Informative message based
      on the authselect integrity check result
    ansible.builtin.assert:
      that:
      - result_authselect_check_cmd.rc == 0
      fail_msg:
      - authselect integrity check failed. Remediation aborted!
      - This remediation could not be applied because an authselect profile was not
        selected or the selected profile is not intact.
      - It is not recommended to manually edit the PAM files when authselect tool
        is available.
      - In cases where the default authselect profile does not cover a specific demand,
        a custom authselect profile is recommended.
      success_msg:
      - authselect integrity check passed

  - name: Lock Accounts After Failed Password Attempts - Get authselect current features
    ansible.builtin.shell:
      cmd: authselect current | tail -n+3 | awk '{ print $2 }'
    register: result_authselect_features
    changed_when: false
    when:
    - result_authselect_check_cmd is success

  - name: Lock Accounts After Failed Password Attempts - Ensure "with-faillock" feature
      is enabled using authselect tool
    ansible.builtin.command:
      cmd: authselect enable-feature with-faillock
    register: result_authselect_enable_feature_cmd
    when:
    - result_authselect_check_cmd is success
    - result_authselect_features.stdout is not search("with-faillock")

  - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
      are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_enable_feature_cmd is not skipped
    - result_authselect_enable_feature_cmd is success
  when:
  - '"pam" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Lock Accounts After Failed Password Attempts - Remediation where authselect
    tool is not present
  block:

  - name: Lock Accounts After Failed Password Attempts - Check if pam_faillock.so
      is already enabled
    ansible.builtin.lineinfile:
      path: /etc/pam.d/system-auth
      regexp: .*auth.*pam_faillock\.so (preauth|authfail)
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_faillock_is_enabled

  - name: Lock Accounts After Failed Password Attempts - Enable pam_faillock.so preauth
      editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: auth        required      pam_faillock.so preauth
      insertbefore: ^auth.*sufficient.*pam_unix\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0

  - name: Lock Accounts After Failed Password Attempts - Enable pam_faillock.so authfail
      editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: auth        required      pam_faillock.so authfail
      insertbefore: ^auth.*required.*pam_deny\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0

  - name: Lock Accounts After Failed Password Attempts - Enable pam_faillock.so account
      section editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: account     required      pam_faillock.so
      insertbefore: ^account.*required.*pam_unix\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0
  when:
  - '"pam" in ansible_facts.packages'
  - not result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_passwords_pam_faillock_deny # promote to variable
  set_fact:
    var_accounts_passwords_pam_faillock_deny: !!str 3
  tags:
    - always

- name: Lock Accounts After Failed Password Attempts - Check the presence of /etc/security/faillock.conf
    file
  ansible.builtin.stat:
    path: /etc/security/faillock.conf
  register: result_faillock_conf_check
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Lock Accounts After Failed Password Attempts - Ensure the pam_faillock.so
    deny parameter in /etc/security/faillock.conf
  ansible.builtin.lineinfile:
    path: /etc/security/faillock.conf
    regexp: ^\s*deny\s*=
    line: deny = {{ var_accounts_passwords_pam_faillock_deny }}
    state: present
  when:
  - '"pam" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Lock Accounts After Failed Password Attempts - Ensure the pam_faillock.so
    deny parameter not in PAM files
  block:

  - name: Lock Accounts After Failed Password Attempts - Check if /etc/pam.d/system-auth
      file is present
    ansible.builtin.stat:
      path: /etc/pam.d/system-auth
    register: result_pam_file_present

  - name: Lock Accounts After Failed Password Attempts - Check the proper remediation
      for the system
    block:

    - name: Lock Accounts After Failed Password Attempts - Define the PAM file to
        be edited as a local fact
      ansible.builtin.set_fact:
        pam_file_path: /etc/pam.d/system-auth

    - name: Lock Accounts After Failed Password Attempts - Check if system relies
        on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present

    - name: Lock Accounts After Failed Password Attempts - Ensure authselect custom
        profile is used if authselect is present
      block:

      - name: Lock Accounts After Failed Password Attempts - Check integrity of authselect
          current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Lock Accounts After Failed Password Attempts - Informative message based
          on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was
            not selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific
            demand, a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Lock Accounts After Failed Password Attempts - Get authselect current
          profile
        ansible.builtin.shell:
          cmd: authselect current -r | awk '{ print $1 }'
        register: result_authselect_profile
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Lock Accounts After Failed Password Attempts - Define the current authselect
          profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is match("custom/")

      - name: Lock Accounts After Failed Password Attempts - Define the new authselect
          custom profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: custom/hardening
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is not match("custom/")

      - name: Lock Accounts After Failed Password Attempts - Get authselect current
          features to also enable them in the custom profile
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")

      - name: Lock Accounts After Failed Password Attempts - Check if any custom profile
          with the same name was already created
        ansible.builtin.stat:
          path: /etc/authselect/{{ authselect_custom_profile }}
        register: result_authselect_custom_profile_present
        changed_when: false
        when:
        - authselect_current_profile is not match("custom/")

      - name: Lock Accounts After Failed Password Attempts - Create an authselect
          custom profile based on the current profile
        ansible.builtin.command:
          cmd: authselect create-profile hardening -b {{ authselect_current_profile
            }}
        when:
        - result_authselect_check_cmd is success
        - authselect_current_profile is not match("custom/")
        - not result_authselect_custom_profile_present.stat.exists

      - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Lock Accounts After Failed Password Attempts - Ensure the authselect
          custom profile is selected
        ansible.builtin.command:
          cmd: authselect select {{ authselect_custom_profile }}
        register: result_pam_authselect_select_profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Lock Accounts After Failed Password Attempts - Restore the authselect
          features in the custom profile
        ansible.builtin.command:
          cmd: authselect enable-feature {{ item }}
        loop: '{{ result_authselect_features.stdout_lines }}'
        register: result_pam_authselect_restore_features
        when:
        - result_authselect_profile is not skipped
        - result_authselect_features is not skipped
        - result_pam_authselect_select_profile is not skipped

      - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - result_pam_authselect_restore_features is not skipped

      - name: Lock Accounts After Failed Password Attempts - Change the PAM file to
          be edited according to the custom authselect profile
        ansible.builtin.set_fact:
          pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
            | basename }}
      when:
      - result_authselect_present.stat.exists

    - name: Lock Accounts After Failed Password Attempts - Define a fact for control
        already filtered in case filters are used
      ansible.builtin.set_fact:
        pam_module_control: ''

    - name: Lock Accounts After Failed Password Attempts - Ensure the "deny" option
        from "pam_faillock.so" is not present in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: (.*auth.*pam_faillock.so.*)\bdeny\b=?[0-9a-zA-Z]*(.*)
        replace: \1\2
      register: result_pam_option_removal

    - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
        are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present.stat.exists
      - result_pam_option_removal is changed
    when:
    - result_pam_file_present.stat.exists

  - name: Lock Accounts After Failed Password Attempts - Check if /etc/pam.d/password-auth
      file is present
    ansible.builtin.stat:
      path: /etc/pam.d/password-auth
    register: result_pam_file_present

  - name: Lock Accounts After Failed Password Attempts - Check the proper remediation
      for the system
    block:

    - name: Lock Accounts After Failed Password Attempts - Define the PAM file to
        be edited as a local fact
      ansible.builtin.set_fact:
        pam_file_path: /etc/pam.d/password-auth

    - name: Lock Accounts After Failed Password Attempts - Check if system relies
        on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present

    - name: Lock Accounts After Failed Password Attempts - Ensure authselect custom
        profile is used if authselect is present
      block:

      - name: Lock Accounts After Failed Password Attempts - Check integrity of authselect
          current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Lock Accounts After Failed Password Attempts - Informative message based
          on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was
            not selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific
            demand, a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Lock Accounts After Failed Password Attempts - Get authselect current
          profile
        ansible.builtin.shell:
          cmd: authselect current -r | awk '{ print $1 }'
        register: result_authselect_profile
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Lock Accounts After Failed Password Attempts - Define the current authselect
          profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is match("custom/")

      - name: Lock Accounts After Failed Password Attempts - Define the new authselect
          custom profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: custom/hardening
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is not match("custom/")

      - name: Lock Accounts After Failed Password Attempts - Get authselect current
          features to also enable them in the custom profile
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")

      - name: Lock Accounts After Failed Password Attempts - Check if any custom profile
          with the same name was already created
        ansible.builtin.stat:
          path: /etc/authselect/{{ authselect_custom_profile }}
        register: result_authselect_custom_profile_present
        changed_when: false
        when:
        - authselect_current_profile is not match("custom/")

      - name: Lock Accounts After Failed Password Attempts - Create an authselect
          custom profile based on the current profile
        ansible.builtin.command:
          cmd: authselect create-profile hardening -b {{ authselect_current_profile
            }}
        when:
        - result_authselect_check_cmd is success
        - authselect_current_profile is not match("custom/")
        - not result_authselect_custom_profile_present.stat.exists

      - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Lock Accounts After Failed Password Attempts - Ensure the authselect
          custom profile is selected
        ansible.builtin.command:
          cmd: authselect select {{ authselect_custom_profile }}
        register: result_pam_authselect_select_profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Lock Accounts After Failed Password Attempts - Restore the authselect
          features in the custom profile
        ansible.builtin.command:
          cmd: authselect enable-feature {{ item }}
        loop: '{{ result_authselect_features.stdout_lines }}'
        register: result_pam_authselect_restore_features
        when:
        - result_authselect_profile is not skipped
        - result_authselect_features is not skipped
        - result_pam_authselect_select_profile is not skipped

      - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - result_pam_authselect_restore_features is not skipped

      - name: Lock Accounts After Failed Password Attempts - Change the PAM file to
          be edited according to the custom authselect profile
        ansible.builtin.set_fact:
          pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
            | basename }}
      when:
      - result_authselect_present.stat.exists

    - name: Lock Accounts After Failed Password Attempts - Define a fact for control
        already filtered in case filters are used
      ansible.builtin.set_fact:
        pam_module_control: ''

    - name: Lock Accounts After Failed Password Attempts - Ensure the "deny" option
        from "pam_faillock.so" is not present in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: (.*auth.*pam_faillock.so.*)\bdeny\b=?[0-9a-zA-Z]*(.*)
        replace: \1\2
      register: result_pam_option_removal

    - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
        are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present.stat.exists
      - result_pam_option_removal is changed
    when:
    - result_pam_file_present.stat.exists
  when:
  - '"pam" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Lock Accounts After Failed Password Attempts - Ensure the pam_faillock.so
    deny parameter in PAM files
  block:

  - name: Lock Accounts After Failed Password Attempts - Check if pam_faillock.so
      deny parameter is already enabled in pam files
    ansible.builtin.lineinfile:
      path: /etc/pam.d/system-auth
      regexp: .*auth.*pam_faillock\.so (preauth|authfail).*deny
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_faillock_deny_parameter_is_present

  - name: Lock Accounts After Failed Password Attempts - Ensure the inclusion of pam_faillock.so
      preauth deny parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
      line: \1required\3 deny={{ var_accounts_passwords_pam_faillock_deny }}
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_deny_parameter_is_present.found == 0

  - name: Lock Accounts After Failed Password Attempts - Ensure the inclusion of pam_faillock.so
      authfail deny parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
      line: \1required\3 deny={{ var_accounts_passwords_pam_faillock_deny }}
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_deny_parameter_is_present.found == 0

  - name: Lock Accounts After Failed Password Attempts - Ensure the desired value
      for pam_faillock.so preauth deny parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)(deny)=[0-9]+(.*)
      line: \1required\3\4={{ var_accounts_passwords_pam_faillock_deny }}\5
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_deny_parameter_is_present.found > 0

  - name: Lock Accounts After Failed Password Attempts - Ensure the desired value
      for pam_faillock.so authfail deny parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)(deny)=[0-9]+(.*)
      line: \1required\3\4={{ var_accounts_passwords_pam_faillock_deny }}\5
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_deny_parameter_is_present.found > 0
  when:
  - '"pam" in ansible_facts.packages'
  - not result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.6
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure the root Account for Failed Password Attempts [ref]

This rule configures the system to lock out the root account after a number of incorrect login attempts using pam_faillock.so. pam_faillock.so module requires multiple entries in pam files. These entries must be carefully defined to work as expected. In order to avoid errors when manually editing these files, it is recommended to use the appropriate tools, such as authselect or authconfig, depending on the OS version.

Rationale:

By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking the account.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_deny_root

References:

cis-csc	1, 12, 15, 16
cobit5	DSS05.04, DSS05.10, DSS06.10
disa	CCI-000044, CCI-002238
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-6(a), AC-7(b), IA-5(c)
nist-csf	PR.AC-7
os-srg	SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005
anssi	R31

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

if [ -f /usr/bin/authselect ]; then
    if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
authselect enable-feature with-faillock

authselect apply-changes -b
else
    
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
    if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
        sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix\.so.*/i auth        required      pam_faillock.so preauth silent' "$pam_file"
        sed -i --follow-symlinks '/^auth.*required.*pam_deny\.so.*/i auth        required      pam_faillock.so authfail' "$pam_file"
        sed -i --follow-symlinks '/^account.*required.*pam_unix\.so.*/i account     required      pam_faillock.so' "$pam_file"
    fi
    sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock\.so)/\1required     \3/g' "$pam_file"
done

fi

AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
SKIP_FAILLOCK_CHECK=false

FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ] || [ "$SKIP_FAILLOCK_CHECK" = "true" ]; then
    regex="^\s*even_deny_root"
    line="even_deny_root"
    if ! grep -q $regex $FAILLOCK_CONF; then
        echo $line >> $FAILLOCK_CONF
    fi
    
    for pam_file in "${AUTH_FILES[@]}"
    do
        if [ -e "$pam_file" ] ; then
            PAM_FILE_PATH="$pam_file"
            if [ -f /usr/bin/authselect ]; then
                
                if ! authselect check; then
                echo "
                authselect integrity check failed. Remediation aborted!
                This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                It is not recommended to manually edit the PAM files when authselect tool is available.
                In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                exit 1
                fi

                CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                # If not already in use, a custom profile is created preserving the enabled features.
                if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                    ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                    authselect create-profile hardening -b $CURRENT_PROFILE
                    CURRENT_PROFILE="custom/hardening"
                    
                    authselect apply-changes -b --backup=before-hardening-custom-profile
                    authselect select $CURRENT_PROFILE
                    for feature in $ENABLED_FEATURES; do
                        authselect enable-feature $feature;
                    done
                    
                    authselect apply-changes -b --backup=after-hardening-custom-profile
                fi
                PAM_FILE_NAME=$(basename "$pam_file")
                PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                authselect apply-changes -b
            fi
            
        if grep -qP "^\s*auth\s.*\bpam_faillock.so\s.*\beven_deny_root\b" "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks "s/(.*auth.*pam_faillock.so.*)\beven_deny_root\b=?[[:alnum:]]*(.*)/\1\2/g" "$PAM_FILE_PATH"
        fi
            if [ -f /usr/bin/authselect ]; then
                
                authselect apply-changes -b
            fi
        else
            echo "$pam_file was not found" >&2
        fi
    done
    
else
    for pam_file in "${AUTH_FILES[@]}"
    do
        if ! grep -qE '^\s*auth.*pam_faillock\.so (preauth|authfail).*even_deny_root' "$pam_file"; then
            sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*preauth.*silent.*/ s/$/ even_deny_root/' "$pam_file"
            sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*authfail.*/ s/$/ even_deny_root/' "$pam_file"
        fi
    done
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(c)
  - accounts_passwords_pam_faillock_deny_root
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure the root Account for Failed Password Attempts - Check if system
    relies on authselect tool
  ansible.builtin.stat:
    path: /usr/bin/authselect
  register: result_authselect_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(c)
  - accounts_passwords_pam_faillock_deny_root
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure the root Account for Failed Password Attempts - Remediation where
    authselect tool is present
  block:

  - name: Configure the root Account for Failed Password Attempts - Check integrity
      of authselect current profile
    ansible.builtin.command:
      cmd: authselect check
    register: result_authselect_check_cmd
    changed_when: false
    failed_when: false

  - name: Configure the root Account for Failed Password Attempts - Informative message
      based on the authselect integrity check result
    ansible.builtin.assert:
      that:
      - result_authselect_check_cmd.rc == 0
      fail_msg:
      - authselect integrity check failed. Remediation aborted!
      - This remediation could not be applied because an authselect profile was not
        selected or the selected profile is not intact.
      - It is not recommended to manually edit the PAM files when authselect tool
        is available.
      - In cases where the default authselect profile does not cover a specific demand,
        a custom authselect profile is recommended.
      success_msg:
      - authselect integrity check passed

  - name: Configure the root Account for Failed Password Attempts - Get authselect
      current features
    ansible.builtin.shell:
      cmd: authselect current | tail -n+3 | awk '{ print $2 }'
    register: result_authselect_features
    changed_when: false
    when:
    - result_authselect_check_cmd is success

  - name: Configure the root Account for Failed Password Attempts - Ensure "with-faillock"
      feature is enabled using authselect tool
    ansible.builtin.command:
      cmd: authselect enable-feature with-faillock
    register: result_authselect_enable_feature_cmd
    when:
    - result_authselect_check_cmd is success
    - result_authselect_features.stdout is not search("with-faillock")

  - name: Configure the root Account for Failed Password Attempts - Ensure authselect
      changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_enable_feature_cmd is not skipped
    - result_authselect_enable_feature_cmd is success
  when:
  - '"pam" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(c)
  - accounts_passwords_pam_faillock_deny_root
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure the root Account for Failed Password Attempts - Remediation where
    authselect tool is not present
  block:

  - name: Configure the root Account for Failed Password Attempts - Check if pam_faillock.so
      is already enabled
    ansible.builtin.lineinfile:
      path: /etc/pam.d/system-auth
      regexp: .*auth.*pam_faillock\.so (preauth|authfail)
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_faillock_is_enabled

  - name: Configure the root Account for Failed Password Attempts - Enable pam_faillock.so
      preauth editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: auth        required      pam_faillock.so preauth
      insertbefore: ^auth.*sufficient.*pam_unix\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0

  - name: Configure the root Account for Failed Password Attempts - Enable pam_faillock.so
      authfail editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: auth        required      pam_faillock.so authfail
      insertbefore: ^auth.*required.*pam_deny\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0

  - name: Configure the root Account for Failed Password Attempts - Enable pam_faillock.so
      account section editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: account     required      pam_faillock.so
      insertbefore: ^account.*required.*pam_unix\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0
  when:
  - '"pam" in ansible_facts.packages'
  - not result_authselect_present.stat.exists
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(c)
  - accounts_passwords_pam_faillock_deny_root
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure the root Account for Failed Password Attempts - Check the presence
    of /etc/security/faillock.conf file
  ansible.builtin.stat:
    path: /etc/security/faillock.conf
  register: result_faillock_conf_check
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(c)
  - accounts_passwords_pam_faillock_deny_root
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure the root Account for Failed Password Attempts - Ensure the pam_faillock.so
    even_deny_root parameter in /etc/security/faillock.conf
  ansible.builtin.lineinfile:
    path: /etc/security/faillock.conf
    regexp: ^\s*even_deny_root
    line: even_deny_root
    state: present
  when:
  - '"pam" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(c)
  - accounts_passwords_pam_faillock_deny_root
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure the root Account for Failed Password Attempts - Ensure the pam_faillock.so
    even_deny_root parameter not in PAM files
  block:

  - name: Configure the root Account for Failed Password Attempts - Check if /etc/pam.d/system-auth
      file is present
    ansible.builtin.stat:
      path: /etc/pam.d/system-auth
    register: result_pam_file_present

  - name: Configure the root Account for Failed Password Attempts - Check the proper
      remediation for the system
    block:

    - name: Configure the root Account for Failed Password Attempts - Define the PAM
        file to be edited as a local fact
      ansible.builtin.set_fact:
        pam_file_path: /etc/pam.d/system-auth

    - name: Configure the root Account for Failed Password Attempts - Check if system
        relies on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present

    - name: Configure the root Account for Failed Password Attempts - Ensure authselect
        custom profile is used if authselect is present
      block:

      - name: Configure the root Account for Failed Password Attempts - Check integrity
          of authselect current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Configure the root Account for Failed Password Attempts - Informative
          message based on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was
            not selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific
            demand, a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Configure the root Account for Failed Password Attempts - Get authselect
          current profile
        ansible.builtin.shell:
          cmd: authselect current -r | awk '{ print $1 }'
        register: result_authselect_profile
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Configure the root Account for Failed Password Attempts - Define the
          current authselect profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is match("custom/")

      - name: Configure the root Account for Failed Password Attempts - Define the
          new authselect custom profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: custom/hardening
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is not match("custom/")

      - name: Configure the root Account for Failed Password Attempts - Get authselect
          current features to also enable them in the custom profile
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")

      - name: Configure the root Account for Failed Password Attempts - Check if any
          custom profile with the same name was already created
        ansible.builtin.stat:
          path: /etc/authselect/{{ authselect_custom_profile }}
        register: result_authselect_custom_profile_present
        changed_when: false
        when:
        - authselect_current_profile is not match("custom/")

      - name: Configure the root Account for Failed Password Attempts - Create an
          authselect custom profile based on the current profile
        ansible.builtin.command:
          cmd: authselect create-profile hardening -b {{ authselect_current_profile
            }}
        when:
        - result_authselect_check_cmd is success
        - authselect_current_profile is not match("custom/")
        - not result_authselect_custom_profile_present.stat.exists

      - name: Configure the root Account for Failed Password Attempts - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Configure the root Account for Failed Password Attempts - Ensure the
          authselect custom profile is selected
        ansible.builtin.command:
          cmd: authselect select {{ authselect_custom_profile }}
        register: result_pam_authselect_select_profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Configure the root Account for Failed Password Attempts - Restore the
          authselect features in the custom profile
        ansible.builtin.command:
          cmd: authselect enable-feature {{ item }}
        loop: '{{ result_authselect_features.stdout_lines }}'
        register: result_pam_authselect_restore_features
        when:
        - result_authselect_profile is not skipped
        - result_authselect_features is not skipped
        - result_pam_authselect_select_profile is not skipped

      - name: Configure the root Account for Failed Password Attempts - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - result_pam_authselect_restore_features is not skipped

      - name: Configure the root Account for Failed Password Attempts - Change the
          PAM file to be edited according to the custom authselect profile
        ansible.builtin.set_fact:
          pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
            | basename }}
      when:
      - result_authselect_present.stat.exists

    - name: Configure the root Account for Failed Password Attempts - Define a fact
        for control already filtered in case filters are used
      ansible.builtin.set_fact:
        pam_module_control: ''

    - name: Configure the root Account for Failed Password Attempts - Ensure the "even_deny_root"
        option from "pam_faillock.so" is not present in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: (.*auth.*pam_faillock.so.*)\beven_deny_root\b=?[0-9a-zA-Z]*(.*)
        replace: \1\2
      register: result_pam_option_removal

    - name: Configure the root Account for Failed Password Attempts - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present.stat.exists
      - result_pam_option_removal is changed
    when:
    - result_pam_file_present.stat.exists

  - name: Configure the root Account for Failed Password Attempts - Check if /etc/pam.d/password-auth
      file is present
    ansible.builtin.stat:
      path: /etc/pam.d/password-auth
    register: result_pam_file_present

  - name: Configure the root Account for Failed Password Attempts - Check the proper
      remediation for the system
    block:

    - name: Configure the root Account for Failed Password Attempts - Define the PAM
        file to be edited as a local fact
      ansible.builtin.set_fact:
        pam_file_path: /etc/pam.d/password-auth

    - name: Configure the root Account for Failed Password Attempts - Check if system
        relies on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present

    - name: Configure the root Account for Failed Password Attempts - Ensure authselect
        custom profile is used if authselect is present
      block:

      - name: Configure the root Account for Failed Password Attempts - Check integrity
          of authselect current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Configure the root Account for Failed Password Attempts - Informative
          message based on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was
            not selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific
            demand, a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Configure the root Account for Failed Password Attempts - Get authselect
          current profile
        ansible.builtin.shell:
          cmd: authselect current -r | awk '{ print $1 }'
        register: result_authselect_profile
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Configure the root Account for Failed Password Attempts - Define the
          current authselect profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is match("custom/")

      - name: Configure the root Account for Failed Password Attempts - Define the
          new authselect custom profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: custom/hardening
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is not match("custom/")

      - name: Configure the root Account for Failed Password Attempts - Get authselect
          current features to also enable them in the custom profile
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")

      - name: Configure the root Account for Failed Password Attempts - Check if any
          custom profile with the same name was already created
        ansible.builtin.stat:
          path: /etc/authselect/{{ authselect_custom_profile }}
        register: result_authselect_custom_profile_present
        changed_when: false
        when:
        - authselect_current_profile is not match("custom/")

      - name: Configure the root Account for Failed Password Attempts - Create an
          authselect custom profile based on the current profile
        ansible.builtin.command:
          cmd: authselect create-profile hardening -b {{ authselect_current_profile
            }}
        when:
        - result_authselect_check_cmd is success
        - authselect_current_profile is not match("custom/")
        - not result_authselect_custom_profile_present.stat.exists

      - name: Configure the root Account for Failed Password Attempts - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Configure the root Account for Failed Password Attempts - Ensure the
          authselect custom profile is selected
        ansible.builtin.command:
          cmd: authselect select {{ authselect_custom_profile }}
        register: result_pam_authselect_select_profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Configure the root Account for Failed Password Attempts - Restore the
          authselect features in the custom profile
        ansible.builtin.command:
          cmd: authselect enable-feature {{ item }}
        loop: '{{ result_authselect_features.stdout_lines }}'
        register: result_pam_authselect_restore_features
        when:
        - result_authselect_profile is not skipped
        - result_authselect_features is not skipped
        - result_pam_authselect_select_profile is not skipped

      - name: Configure the root Account for Failed Password Attempts - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - result_pam_authselect_restore_features is not skipped

      - name: Configure the root Account for Failed Password Attempts - Change the
          PAM file to be edited according to the custom authselect profile
        ansible.builtin.set_fact:
          pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
            | basename }}
      when:
      - result_authselect_present.stat.exists

    - name: Configure the root Account for Failed Password Attempts - Define a fact
        for control already filtered in case filters are used
      ansible.builtin.set_fact:
        pam_module_control: ''

    - name: Configure the root Account for Failed Password Attempts - Ensure the "even_deny_root"
        option from "pam_faillock.so" is not present in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: (.*auth.*pam_faillock.so.*)\beven_deny_root\b=?[0-9a-zA-Z]*(.*)
        replace: \1\2
      register: result_pam_option_removal

    - name: Configure the root Account for Failed Password Attempts - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present.stat.exists
      - result_pam_option_removal is changed
    when:
    - result_pam_file_present.stat.exists
  when:
  - '"pam" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(c)
  - accounts_passwords_pam_faillock_deny_root
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure the root Account for Failed Password Attempts - Ensure the pam_faillock.so
    even_deny_root parameter in PAM files
  block:

  - name: Configure the root Account for Failed Password Attempts - Check if pam_faillock.so
      even_deny_root parameter is already enabled in pam files
    ansible.builtin.lineinfile:
      path: /etc/pam.d/system-auth
      regexp: .*auth.*pam_faillock\.so (preauth|authfail).*even_deny_root
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_faillock_even_deny_root_parameter_is_present

  - name: Configure the root Account for Failed Password Attempts - Ensure the inclusion
      of pam_faillock.so preauth even_deny_root parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
      line: \1required\3 even_deny_root
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_even_deny_root_parameter_is_present.found == 0

  - name: Configure the root Account for Failed Password Attempts - Ensure the inclusion
      of pam_faillock.so authfail even_deny_root parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
      line: \1required\3 even_deny_root
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_even_deny_root_parameter_is_present.found == 0
  when:
  - '"pam" in ansible_facts.packages'
  - not result_faillock_conf_check.stat.exists
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(c)
  - accounts_passwords_pam_faillock_deny_root
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Set Interval For Counting Failed Password Attempts [ref]

Utilizing pam_faillock.so, the fail_interval directive configures the system to lock out an account after a number of incorrect login attempts within a specified time period. Ensure that the file /etc/security/faillock.conf contains the following entry: fail_interval = <interval-in-seconds> where interval-in-seconds is 900 or greater. In order to avoid errors when manually editing these files, it is recommended to use the appropriate tools, such as authselect or authconfig, depending on the OS version.

Rationale:

By limiting the number of failed logon attempts the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_interval

References:

cis-csc	1, 12, 15, 16
cobit5	DSS05.04, DSS05.10, DSS06.10
disa	CCI-000044, CCI-002238
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-6(a), AC-7(a)
nist-csf	PR.AC-7
ospp	FIA_AFL.1
os-srg	SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005
anssi	R31

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_accounts_passwords_pam_faillock_fail_interval='900'


if [ -f /usr/bin/authselect ]; then
    if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
authselect enable-feature with-faillock

authselect apply-changes -b
else
    
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
    if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
        sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix\.so.*/i auth        required      pam_faillock.so preauth silent' "$pam_file"
        sed -i --follow-symlinks '/^auth.*required.*pam_deny\.so.*/i auth        required      pam_faillock.so authfail' "$pam_file"
        sed -i --follow-symlinks '/^account.*required.*pam_unix\.so.*/i account     required      pam_faillock.so' "$pam_file"
    fi
    sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock\.so)/\1required     \3/g' "$pam_file"
done

fi

AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
SKIP_FAILLOCK_CHECK=false

FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ] || [ "$SKIP_FAILLOCK_CHECK" = "true" ]; then
    regex="^\s*fail_interval\s*="
    line="fail_interval = $var_accounts_passwords_pam_faillock_fail_interval"
    if ! grep -q $regex $FAILLOCK_CONF; then
        echo $line >> $FAILLOCK_CONF
    else
        sed -i --follow-symlinks 's|^\s*\(fail_interval\s*=\s*\)\(\S\+\)|\1'"$var_accounts_passwords_pam_faillock_fail_interval"'|g' $FAILLOCK_CONF
    fi
    
    for pam_file in "${AUTH_FILES[@]}"
    do
        if [ -e "$pam_file" ] ; then
            PAM_FILE_PATH="$pam_file"
            if [ -f /usr/bin/authselect ]; then
                
                if ! authselect check; then
                echo "
                authselect integrity check failed. Remediation aborted!
                This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                It is not recommended to manually edit the PAM files when authselect tool is available.
                In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                exit 1
                fi

                CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                # If not already in use, a custom profile is created preserving the enabled features.
                if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                    ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                    authselect create-profile hardening -b $CURRENT_PROFILE
                    CURRENT_PROFILE="custom/hardening"
                    
                    authselect apply-changes -b --backup=before-hardening-custom-profile
                    authselect select $CURRENT_PROFILE
                    for feature in $ENABLED_FEATURES; do
                        authselect enable-feature $feature;
                    done
                    
                    authselect apply-changes -b --backup=after-hardening-custom-profile
                fi
                PAM_FILE_NAME=$(basename "$pam_file")
                PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                authselect apply-changes -b
            fi
            
        if grep -qP "^\s*auth\s.*\bpam_faillock.so\s.*\bfail_interval\b" "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks "s/(.*auth.*pam_faillock.so.*)\bfail_interval\b=?[[:alnum:]]*(.*)/\1\2/g" "$PAM_FILE_PATH"
        fi
            if [ -f /usr/bin/authselect ]; then
                
                authselect apply-changes -b
            fi
        else
            echo "$pam_file was not found" >&2
        fi
    done
    
else
    for pam_file in "${AUTH_FILES[@]}"
    do
        if ! grep -qE '^\s*auth.*pam_faillock\.so (preauth|authfail).*fail_interval' "$pam_file"; then
            sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*preauth.*silent.*/ s/$/ fail_interval='"$var_accounts_passwords_pam_faillock_fail_interval"'/' "$pam_file"
            sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*authfail.*/ s/$/ fail_interval='"$var_accounts_passwords_pam_faillock_fail_interval"'/' "$pam_file"
        else
            sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*preauth.*silent.*\)\('"fail_interval"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_fail_interval"'\3/' "$pam_file"
            sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*authfail.*\)\('"fail_interval"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_fail_interval"'\3/' "$pam_file"
        fi
    done
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - accounts_passwords_pam_faillock_interval
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Interval For Counting Failed Password Attempts - Check if system relies
    on authselect tool
  ansible.builtin.stat:
    path: /usr/bin/authselect
  register: result_authselect_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - accounts_passwords_pam_faillock_interval
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Interval For Counting Failed Password Attempts - Remediation where authselect
    tool is present
  block:

  - name: Set Interval For Counting Failed Password Attempts - Check integrity of
      authselect current profile
    ansible.builtin.command:
      cmd: authselect check
    register: result_authselect_check_cmd
    changed_when: false
    failed_when: false

  - name: Set Interval For Counting Failed Password Attempts - Informative message
      based on the authselect integrity check result
    ansible.builtin.assert:
      that:
      - result_authselect_check_cmd.rc == 0
      fail_msg:
      - authselect integrity check failed. Remediation aborted!
      - This remediation could not be applied because an authselect profile was not
        selected or the selected profile is not intact.
      - It is not recommended to manually edit the PAM files when authselect tool
        is available.
      - In cases where the default authselect profile does not cover a specific demand,
        a custom authselect profile is recommended.
      success_msg:
      - authselect integrity check passed

  - name: Set Interval For Counting Failed Password Attempts - Get authselect current
      features
    ansible.builtin.shell:
      cmd: authselect current | tail -n+3 | awk '{ print $2 }'
    register: result_authselect_features
    changed_when: false
    when:
    - result_authselect_check_cmd is success

  - name: Set Interval For Counting Failed Password Attempts - Ensure "with-faillock"
      feature is enabled using authselect tool
    ansible.builtin.command:
      cmd: authselect enable-feature with-faillock
    register: result_authselect_enable_feature_cmd
    when:
    - result_authselect_check_cmd is success
    - result_authselect_features.stdout is not search("with-faillock")

  - name: Set Interval For Counting Failed Password Attempts - Ensure authselect changes
      are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_enable_feature_cmd is not skipped
    - result_authselect_enable_feature_cmd is success
  when:
  - '"pam" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - accounts_passwords_pam_faillock_interval
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Interval For Counting Failed Password Attempts - Remediation where authselect
    tool is not present
  block:

  - name: Set Interval For Counting Failed Password Attempts - Check if pam_faillock.so
      is already enabled
    ansible.builtin.lineinfile:
      path: /etc/pam.d/system-auth
      regexp: .*auth.*pam_faillock\.so (preauth|authfail)
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_faillock_is_enabled

  - name: Set Interval For Counting Failed Password Attempts - Enable pam_faillock.so
      preauth editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: auth        required      pam_faillock.so preauth
      insertbefore: ^auth.*sufficient.*pam_unix\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0

  - name: Set Interval For Counting Failed Password Attempts - Enable pam_faillock.so
      authfail editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: auth        required      pam_faillock.so authfail
      insertbefore: ^auth.*required.*pam_deny\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0

  - name: Set Interval For Counting Failed Password Attempts - Enable pam_faillock.so
      account section editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: account     required      pam_faillock.so
      insertbefore: ^account.*required.*pam_unix\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0
  when:
  - '"pam" in ansible_facts.packages'
  - not result_authselect_present.stat.exists
  tags:
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - accounts_passwords_pam_faillock_interval
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_passwords_pam_faillock_fail_interval # promote to variable
  set_fact:
    var_accounts_passwords_pam_faillock_fail_interval: !!str 900
  tags:
    - always

- name: Set Interval For Counting Failed Password Attempts - Check the presence of
    /etc/security/faillock.conf file
  ansible.builtin.stat:
    path: /etc/security/faillock.conf
  register: result_faillock_conf_check
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - accounts_passwords_pam_faillock_interval
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Interval For Counting Failed Password Attempts - Ensure the pam_faillock.so
    fail_interval parameter in /etc/security/faillock.conf
  ansible.builtin.lineinfile:
    path: /etc/security/faillock.conf
    regexp: ^\s*fail_interval\s*=
    line: fail_interval = {{ var_accounts_passwords_pam_faillock_fail_interval }}
    state: present
  when:
  - '"pam" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - accounts_passwords_pam_faillock_interval
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Interval For Counting Failed Password Attempts - Ensure the pam_faillock.so
    fail_interval parameter not in PAM files
  block:

  - name: Set Interval For Counting Failed Password Attempts - Check if /etc/pam.d/system-auth
      file is present
    ansible.builtin.stat:
      path: /etc/pam.d/system-auth
    register: result_pam_file_present

  - name: Set Interval For Counting Failed Password Attempts - Check the proper remediation
      for the system
    block:

    - name: Set Interval For Counting Failed Password Attempts - Define the PAM file
        to be edited as a local fact
      ansible.builtin.set_fact:
        pam_file_path: /etc/pam.d/system-auth

    - name: Set Interval For Counting Failed Password Attempts - Check if system relies
        on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present

    - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
        custom profile is used if authselect is present
      block:

      - name: Set Interval For Counting Failed Password Attempts - Check integrity
          of authselect current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Set Interval For Counting Failed Password Attempts - Informative message
          based on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was
            not selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific
            demand, a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Set Interval For Counting Failed Password Attempts - Get authselect
          current profile
        ansible.builtin.shell:
          cmd: authselect current -r | awk '{ print $1 }'
        register: result_authselect_profile
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Set Interval For Counting Failed Password Attempts - Define the current
          authselect profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is match("custom/")

      - name: Set Interval For Counting Failed Password Attempts - Define the new
          authselect custom profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: custom/hardening
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is not match("custom/")

      - name: Set Interval For Counting Failed Password Attempts - Get authselect
          current features to also enable them in the custom profile
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")

      - name: Set Interval For Counting Failed Password Attempts - Check if any custom
          profile with the same name was already created
        ansible.builtin.stat:
          path: /etc/authselect/{{ authselect_custom_profile }}
        register: result_authselect_custom_profile_present
        changed_when: false
        when:
        - authselect_current_profile is not match("custom/")

      - name: Set Interval For Counting Failed Password Attempts - Create an authselect
          custom profile based on the current profile
        ansible.builtin.command:
          cmd: authselect create-profile hardening -b {{ authselect_current_profile
            }}
        when:
        - result_authselect_check_cmd is success
        - authselect_current_profile is not match("custom/")
        - not result_authselect_custom_profile_present.stat.exists

      - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Set Interval For Counting Failed Password Attempts - Ensure the authselect
          custom profile is selected
        ansible.builtin.command:
          cmd: authselect select {{ authselect_custom_profile }}
        register: result_pam_authselect_select_profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Set Interval For Counting Failed Password Attempts - Restore the authselect
          features in the custom profile
        ansible.builtin.command:
          cmd: authselect enable-feature {{ item }}
        loop: '{{ result_authselect_features.stdout_lines }}'
        register: result_pam_authselect_restore_features
        when:
        - result_authselect_profile is not skipped
        - result_authselect_features is not skipped
        - result_pam_authselect_select_profile is not skipped

      - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - result_pam_authselect_restore_features is not skipped

      - name: Set Interval For Counting Failed Password Attempts - Change the PAM
          file to be edited according to the custom authselect profile
        ansible.builtin.set_fact:
          pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
            | basename }}
      when:
      - result_authselect_present.stat.exists

    - name: Set Interval For Counting Failed Password Attempts - Define a fact for
        control already filtered in case filters are used
      ansible.builtin.set_fact:
        pam_module_control: ''

    - name: Set Interval For Counting Failed Password Attempts - Ensure the "fail_interval"
        option from "pam_faillock.so" is not present in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: (.*auth.*pam_faillock.so.*)\bfail_interval\b=?[0-9a-zA-Z]*(.*)
        replace: \1\2
      register: result_pam_option_removal

    - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present.stat.exists
      - result_pam_option_removal is changed
    when:
    - result_pam_file_present.stat.exists

  - name: Set Interval For Counting Failed Password Attempts - Check if /etc/pam.d/password-auth
      file is present
    ansible.builtin.stat:
      path: /etc/pam.d/password-auth
    register: result_pam_file_present

  - name: Set Interval For Counting Failed Password Attempts - Check the proper remediation
      for the system
    block:

    - name: Set Interval For Counting Failed Password Attempts - Define the PAM file
        to be edited as a local fact
      ansible.builtin.set_fact:
        pam_file_path: /etc/pam.d/password-auth

    - name: Set Interval For Counting Failed Password Attempts - Check if system relies
        on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present

    - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
        custom profile is used if authselect is present
      block:

      - name: Set Interval For Counting Failed Password Attempts - Check integrity
          of authselect current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Set Interval For Counting Failed Password Attempts - Informative message
          based on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was
            not selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific
            demand, a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Set Interval For Counting Failed Password Attempts - Get authselect
          current profile
        ansible.builtin.shell:
          cmd: authselect current -r | awk '{ print $1 }'
        register: result_authselect_profile
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Set Interval For Counting Failed Password Attempts - Define the current
          authselect profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is match("custom/")

      - name: Set Interval For Counting Failed Password Attempts - Define the new
          authselect custom profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: custom/hardening
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is not match("custom/")

      - name: Set Interval For Counting Failed Password Attempts - Get authselect
          current features to also enable them in the custom profile
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")

      - name: Set Interval For Counting Failed Password Attempts - Check if any custom
          profile with the same name was already created
        ansible.builtin.stat:
          path: /etc/authselect/{{ authselect_custom_profile }}
        register: result_authselect_custom_profile_present
        changed_when: false
        when:
        - authselect_current_profile is not match("custom/")

      - name: Set Interval For Counting Failed Password Attempts - Create an authselect
          custom profile based on the current profile
        ansible.builtin.command:
          cmd: authselect create-profile hardening -b {{ authselect_current_profile
            }}
        when:
        - result_authselect_check_cmd is success
        - authselect_current_profile is not match("custom/")
        - not result_authselect_custom_profile_present.stat.exists

      - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Set Interval For Counting Failed Password Attempts - Ensure the authselect
          custom profile is selected
        ansible.builtin.command:
          cmd: authselect select {{ authselect_custom_profile }}
        register: result_pam_authselect_select_profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Set Interval For Counting Failed Password Attempts - Restore the authselect
          features in the custom profile
        ansible.builtin.command:
          cmd: authselect enable-feature {{ item }}
        loop: '{{ result_authselect_features.stdout_lines }}'
        register: result_pam_authselect_restore_features
        when:
        - result_authselect_profile is not skipped
        - result_authselect_features is not skipped
        - result_pam_authselect_select_profile is not skipped

      - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - result_pam_authselect_restore_features is not skipped

      - name: Set Interval For Counting Failed Password Attempts - Change the PAM
          file to be edited according to the custom authselect profile
        ansible.builtin.set_fact:
          pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
            | basename }}
      when:
      - result_authselect_present.stat.exists

    - name: Set Interval For Counting Failed Password Attempts - Define a fact for
        control already filtered in case filters are used
      ansible.builtin.set_fact:
        pam_module_control: ''

    - name: Set Interval For Counting Failed Password Attempts - Ensure the "fail_interval"
        option from "pam_faillock.so" is not present in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: (.*auth.*pam_faillock.so.*)\bfail_interval\b=?[0-9a-zA-Z]*(.*)
        replace: \1\2
      register: result_pam_option_removal

    - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present.stat.exists
      - result_pam_option_removal is changed
    when:
    - result_pam_file_present.stat.exists
  when:
  - '"pam" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - accounts_passwords_pam_faillock_interval
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Interval For Counting Failed Password Attempts - Ensure the pam_faillock.so
    fail_interval parameter in PAM files
  block:

  - name: Set Interval For Counting Failed Password Attempts - Check if pam_faillock.so
      fail_interval parameter is already enabled in pam files
    ansible.builtin.lineinfile:
      path: /etc/pam.d/system-auth
      regexp: .*auth.*pam_faillock\.so (preauth|authfail).*fail_interval
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_faillock_fail_interval_parameter_is_present

  - name: Set Interval For Counting Failed Password Attempts - Ensure the inclusion
      of pam_faillock.so preauth fail_interval parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
      line: \1required\3 fail_interval={{ var_accounts_passwords_pam_faillock_fail_interval
        }}
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_fail_interval_parameter_is_present.found == 0

  - name: Set Interval For Counting Failed Password Attempts - Ensure the inclusion
      of pam_faillock.so authfail fail_interval parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
      line: \1required\3 fail_interval={{ var_accounts_passwords_pam_faillock_fail_interval
        }}
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_fail_interval_parameter_is_present.found == 0

  - name: Set Interval For Counting Failed Password Attempts - Ensure the desired
      value for pam_faillock.so preauth fail_interval parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)(fail_interval)=[0-9]+(.*)
      line: \1required\3\4={{ var_accounts_passwords_pam_faillock_fail_interval }}\5
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_fail_interval_parameter_is_present.found > 0

  - name: Set Interval For Counting Failed Password Attempts - Ensure the desired
      value for pam_faillock.so authfail fail_interval parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)(fail_interval)=[0-9]+(.*)
      line: \1required\3\4={{ var_accounts_passwords_pam_faillock_fail_interval }}\5
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_fail_interval_parameter_is_present.found > 0
  when:
  - '"pam" in ansible_facts.packages'
  - not result_faillock_conf_check.stat.exists
  tags:
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - accounts_passwords_pam_faillock_interval
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Set Lockout Time for Failed Password Attempts [ref]

This rule configures the system to lock out accounts during a specified time period after a number of incorrect login attempts using pam_faillock.so. Ensure that the file /etc/security/faillock.conf contains the following entry: unlock_time=<interval-in-seconds> where interval-in-seconds is 0 or greater. pam_faillock.so module requires multiple entries in pam files. These entries must be carefully defined to work as expected. In order to avoid any errors when manually editing these files, it is recommended to use the appropriate tools, such as authselect or authconfig, depending on the OS version. If unlock_time is set to 0, manual intervention by an administrator is required to unlock a user. This should be done using the faillock tool.

Warning: If the system supports the new /etc/security/faillock.conf file but the pam_faillock.so parameters are defined directly in /etc/pam.d/system-auth and /etc/pam.d/password-auth, the remediation will migrate the unlock_time parameter to /etc/security/faillock.conf to ensure compatibility with authselect tool. The parameters deny and fail_interval, if used, also have to be migrated by their respective remediation.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_unlock_time

References:

cis-csc	1, 12, 15, 16
cjis	5.5.3
cobit5	DSS05.04, DSS05.10, DSS06.10
cui	3.1.8
disa	CCI-000044, CCI-002238
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-6(a), AC-7(b)
nist-csf	PR.AC-7
ospp	FIA_AFL.1
pcidss	Req-8.1.7
os-srg	SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005
anssi	R31
pcidss4	8.3.4, 8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_accounts_passwords_pam_faillock_unlock_time='0'


if [ -f /usr/bin/authselect ]; then
    if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
authselect enable-feature with-faillock

authselect apply-changes -b
else
    
AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
for pam_file in "${AUTH_FILES[@]}"
do
    if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
        sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix\.so.*/i auth        required      pam_faillock.so preauth silent' "$pam_file"
        sed -i --follow-symlinks '/^auth.*required.*pam_deny\.so.*/i auth        required      pam_faillock.so authfail' "$pam_file"
        sed -i --follow-symlinks '/^account.*required.*pam_unix\.so.*/i account     required      pam_faillock.so' "$pam_file"
    fi
    sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock\.so)/\1required     \3/g' "$pam_file"
done

fi

AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
SKIP_FAILLOCK_CHECK=false

FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ] || [ "$SKIP_FAILLOCK_CHECK" = "true" ]; then
    regex="^\s*unlock_time\s*="
    line="unlock_time = $var_accounts_passwords_pam_faillock_unlock_time"
    if ! grep -q $regex $FAILLOCK_CONF; then
        echo $line >> $FAILLOCK_CONF
    else
        sed -i --follow-symlinks 's|^\s*\(unlock_time\s*=\s*\)\(\S\+\)|\1'"$var_accounts_passwords_pam_faillock_unlock_time"'|g' $FAILLOCK_CONF
    fi
    
    for pam_file in "${AUTH_FILES[@]}"
    do
        if [ -e "$pam_file" ] ; then
            PAM_FILE_PATH="$pam_file"
            if [ -f /usr/bin/authselect ]; then
                
                if ! authselect check; then
                echo "
                authselect integrity check failed. Remediation aborted!
                This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                It is not recommended to manually edit the PAM files when authselect tool is available.
                In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                exit 1
                fi

                CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                # If not already in use, a custom profile is created preserving the enabled features.
                if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                    ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                    authselect create-profile hardening -b $CURRENT_PROFILE
                    CURRENT_PROFILE="custom/hardening"
                    
                    authselect apply-changes -b --backup=before-hardening-custom-profile
                    authselect select $CURRENT_PROFILE
                    for feature in $ENABLED_FEATURES; do
                        authselect enable-feature $feature;
                    done
                    
                    authselect apply-changes -b --backup=after-hardening-custom-profile
                fi
                PAM_FILE_NAME=$(basename "$pam_file")
                PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                authselect apply-changes -b
            fi
            
        if grep -qP "^\s*auth\s.*\bpam_faillock.so\s.*\bunlock_time\b" "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks "s/(.*auth.*pam_faillock.so.*)\bunlock_time\b=?[[:alnum:]]*(.*)/\1\2/g" "$PAM_FILE_PATH"
        fi
            if [ -f /usr/bin/authselect ]; then
                
                authselect apply-changes -b
            fi
        else
            echo "$pam_file was not found" >&2
        fi
    done
    
else
    for pam_file in "${AUTH_FILES[@]}"
    do
        if ! grep -qE '^\s*auth.*pam_faillock\.so (preauth|authfail).*unlock_time' "$pam_file"; then
            sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*preauth.*silent.*/ s/$/ unlock_time='"$var_accounts_passwords_pam_faillock_unlock_time"'/' "$pam_file"
            sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*authfail.*/ s/$/ unlock_time='"$var_accounts_passwords_pam_faillock_unlock_time"'/' "$pam_file"
        else
            sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*preauth.*silent.*\)\('"unlock_time"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_unlock_time"'\3/' "$pam_file"
            sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*authfail.*\)\('"unlock_time"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_unlock_time"'\3/' "$pam_file"
        fi
    done
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.7
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_unlock_time
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Lockout Time for Failed Password Attempts - Check if system relies on
    authselect tool
  ansible.builtin.stat:
    path: /usr/bin/authselect
  register: result_authselect_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.7
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_unlock_time
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Lockout Time for Failed Password Attempts - Remediation where authselect
    tool is present
  block:

  - name: Set Lockout Time for Failed Password Attempts - Check integrity of authselect
      current profile
    ansible.builtin.command:
      cmd: authselect check
    register: result_authselect_check_cmd
    changed_when: false
    failed_when: false

  - name: Set Lockout Time for Failed Password Attempts - Informative message based
      on the authselect integrity check result
    ansible.builtin.assert:
      that:
      - result_authselect_check_cmd.rc == 0
      fail_msg:
      - authselect integrity check failed. Remediation aborted!
      - This remediation could not be applied because an authselect profile was not
        selected or the selected profile is not intact.
      - It is not recommended to manually edit the PAM files when authselect tool
        is available.
      - In cases where the default authselect profile does not cover a specific demand,
        a custom authselect profile is recommended.
      success_msg:
      - authselect integrity check passed

  - name: Set Lockout Time for Failed Password Attempts - Get authselect current features
    ansible.builtin.shell:
      cmd: authselect current | tail -n+3 | awk '{ print $2 }'
    register: result_authselect_features
    changed_when: false
    when:
    - result_authselect_check_cmd is success

  - name: Set Lockout Time for Failed Password Attempts - Ensure "with-faillock" feature
      is enabled using authselect tool
    ansible.builtin.command:
      cmd: authselect enable-feature with-faillock
    register: result_authselect_enable_feature_cmd
    when:
    - result_authselect_check_cmd is success
    - result_authselect_features.stdout is not search("with-faillock")

  - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
      are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_enable_feature_cmd is not skipped
    - result_authselect_enable_feature_cmd is success
  when:
  - '"pam" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.7
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_unlock_time
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Lockout Time for Failed Password Attempts - Remediation where authselect
    tool is not present
  block:

  - name: Set Lockout Time for Failed Password Attempts - Check if pam_faillock.so
      is already enabled
    ansible.builtin.lineinfile:
      path: /etc/pam.d/system-auth
      regexp: .*auth.*pam_faillock\.so (preauth|authfail)
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_faillock_is_enabled

  - name: Set Lockout Time for Failed Password Attempts - Enable pam_faillock.so preauth
      editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: auth        required      pam_faillock.so preauth
      insertbefore: ^auth.*sufficient.*pam_unix\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0

  - name: Set Lockout Time for Failed Password Attempts - Enable pam_faillock.so authfail
      editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: auth        required      pam_faillock.so authfail
      insertbefore: ^auth.*required.*pam_deny\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0

  - name: Set Lockout Time for Failed Password Attempts - Enable pam_faillock.so account
      section editing PAM files
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      line: account     required      pam_faillock.so
      insertbefore: ^account.*required.*pam_unix\.so.*
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_is_enabled.found == 0
  when:
  - '"pam" in ansible_facts.packages'
  - not result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.7
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_unlock_time
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_passwords_pam_faillock_unlock_time # promote to variable
  set_fact:
    var_accounts_passwords_pam_faillock_unlock_time: !!str 0
  tags:
    - always

- name: Set Lockout Time for Failed Password Attempts - Check the presence of /etc/security/faillock.conf
    file
  ansible.builtin.stat:
    path: /etc/security/faillock.conf
  register: result_faillock_conf_check
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.7
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_unlock_time
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Lockout Time for Failed Password Attempts - Ensure the pam_faillock.so
    unlock_time parameter in /etc/security/faillock.conf
  ansible.builtin.lineinfile:
    path: /etc/security/faillock.conf
    regexp: ^\s*unlock_time\s*=
    line: unlock_time = {{ var_accounts_passwords_pam_faillock_unlock_time }}
    state: present
  when:
  - '"pam" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.7
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_unlock_time
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Lockout Time for Failed Password Attempts - Ensure the pam_faillock.so
    unlock_time parameter not in PAM files
  block:

  - name: Set Lockout Time for Failed Password Attempts - Check if /etc/pam.d/system-auth
      file is present
    ansible.builtin.stat:
      path: /etc/pam.d/system-auth
    register: result_pam_file_present

  - name: Set Lockout Time for Failed Password Attempts - Check the proper remediation
      for the system
    block:

    - name: Set Lockout Time for Failed Password Attempts - Define the PAM file to
        be edited as a local fact
      ansible.builtin.set_fact:
        pam_file_path: /etc/pam.d/system-auth

    - name: Set Lockout Time for Failed Password Attempts - Check if system relies
        on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present

    - name: Set Lockout Time for Failed Password Attempts - Ensure authselect custom
        profile is used if authselect is present
      block:

      - name: Set Lockout Time for Failed Password Attempts - Check integrity of authselect
          current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Set Lockout Time for Failed Password Attempts - Informative message
          based on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was
            not selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific
            demand, a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Set Lockout Time for Failed Password Attempts - Get authselect current
          profile
        ansible.builtin.shell:
          cmd: authselect current -r | awk '{ print $1 }'
        register: result_authselect_profile
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Set Lockout Time for Failed Password Attempts - Define the current authselect
          profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is match("custom/")

      - name: Set Lockout Time for Failed Password Attempts - Define the new authselect
          custom profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: custom/hardening
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is not match("custom/")

      - name: Set Lockout Time for Failed Password Attempts - Get authselect current
          features to also enable them in the custom profile
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")

      - name: Set Lockout Time for Failed Password Attempts - Check if any custom
          profile with the same name was already created
        ansible.builtin.stat:
          path: /etc/authselect/{{ authselect_custom_profile }}
        register: result_authselect_custom_profile_present
        changed_when: false
        when:
        - authselect_current_profile is not match("custom/")

      - name: Set Lockout Time for Failed Password Attempts - Create an authselect
          custom profile based on the current profile
        ansible.builtin.command:
          cmd: authselect create-profile hardening -b {{ authselect_current_profile
            }}
        when:
        - result_authselect_check_cmd is success
        - authselect_current_profile is not match("custom/")
        - not result_authselect_custom_profile_present.stat.exists

      - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Set Lockout Time for Failed Password Attempts - Ensure the authselect
          custom profile is selected
        ansible.builtin.command:
          cmd: authselect select {{ authselect_custom_profile }}
        register: result_pam_authselect_select_profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Set Lockout Time for Failed Password Attempts - Restore the authselect
          features in the custom profile
        ansible.builtin.command:
          cmd: authselect enable-feature {{ item }}
        loop: '{{ result_authselect_features.stdout_lines }}'
        register: result_pam_authselect_restore_features
        when:
        - result_authselect_profile is not skipped
        - result_authselect_features is not skipped
        - result_pam_authselect_select_profile is not skipped

      - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - result_pam_authselect_restore_features is not skipped

      - name: Set Lockout Time for Failed Password Attempts - Change the PAM file
          to be edited according to the custom authselect profile
        ansible.builtin.set_fact:
          pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
            | basename }}
      when:
      - result_authselect_present.stat.exists

    - name: Set Lockout Time for Failed Password Attempts - Define a fact for control
        already filtered in case filters are used
      ansible.builtin.set_fact:
        pam_module_control: ''

    - name: Set Lockout Time for Failed Password Attempts - Ensure the "unlock_time"
        option from "pam_faillock.so" is not present in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: (.*auth.*pam_faillock.so.*)\bunlock_time\b=?[0-9a-zA-Z]*(.*)
        replace: \1\2
      register: result_pam_option_removal

    - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
        are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present.stat.exists
      - result_pam_option_removal is changed
    when:
    - result_pam_file_present.stat.exists

  - name: Set Lockout Time for Failed Password Attempts - Check if /etc/pam.d/password-auth
      file is present
    ansible.builtin.stat:
      path: /etc/pam.d/password-auth
    register: result_pam_file_present

  - name: Set Lockout Time for Failed Password Attempts - Check the proper remediation
      for the system
    block:

    - name: Set Lockout Time for Failed Password Attempts - Define the PAM file to
        be edited as a local fact
      ansible.builtin.set_fact:
        pam_file_path: /etc/pam.d/password-auth

    - name: Set Lockout Time for Failed Password Attempts - Check if system relies
        on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present

    - name: Set Lockout Time for Failed Password Attempts - Ensure authselect custom
        profile is used if authselect is present
      block:

      - name: Set Lockout Time for Failed Password Attempts - Check integrity of authselect
          current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Set Lockout Time for Failed Password Attempts - Informative message
          based on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was
            not selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific
            demand, a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Set Lockout Time for Failed Password Attempts - Get authselect current
          profile
        ansible.builtin.shell:
          cmd: authselect current -r | awk '{ print $1 }'
        register: result_authselect_profile
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Set Lockout Time for Failed Password Attempts - Define the current authselect
          profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is match("custom/")

      - name: Set Lockout Time for Failed Password Attempts - Define the new authselect
          custom profile as a local fact
        ansible.builtin.set_fact:
          authselect_current_profile: '{{ result_authselect_profile.stdout }}'
          authselect_custom_profile: custom/hardening
        when:
        - result_authselect_profile is not skipped
        - result_authselect_profile.stdout is not match("custom/")

      - name: Set Lockout Time for Failed Password Attempts - Get authselect current
          features to also enable them in the custom profile
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")

      - name: Set Lockout Time for Failed Password Attempts - Check if any custom
          profile with the same name was already created
        ansible.builtin.stat:
          path: /etc/authselect/{{ authselect_custom_profile }}
        register: result_authselect_custom_profile_present
        changed_when: false
        when:
        - authselect_current_profile is not match("custom/")

      - name: Set Lockout Time for Failed Password Attempts - Create an authselect
          custom profile based on the current profile
        ansible.builtin.command:
          cmd: authselect create-profile hardening -b {{ authselect_current_profile
            }}
        when:
        - result_authselect_check_cmd is success
        - authselect_current_profile is not match("custom/")
        - not result_authselect_custom_profile_present.stat.exists

      - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Set Lockout Time for Failed Password Attempts - Ensure the authselect
          custom profile is selected
        ansible.builtin.command:
          cmd: authselect select {{ authselect_custom_profile }}
        register: result_pam_authselect_select_profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - authselect_current_profile is not match("custom/")
        - authselect_custom_profile is not match(authselect_current_profile)

      - name: Set Lockout Time for Failed Password Attempts - Restore the authselect
          features in the custom profile
        ansible.builtin.command:
          cmd: authselect enable-feature {{ item }}
        loop: '{{ result_authselect_features.stdout_lines }}'
        register: result_pam_authselect_restore_features
        when:
        - result_authselect_profile is not skipped
        - result_authselect_features is not skipped
        - result_pam_authselect_select_profile is not skipped

      - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
        when:
        - result_authselect_check_cmd is success
        - result_authselect_profile is not skipped
        - result_pam_authselect_restore_features is not skipped

      - name: Set Lockout Time for Failed Password Attempts - Change the PAM file
          to be edited according to the custom authselect profile
        ansible.builtin.set_fact:
          pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
            | basename }}
      when:
      - result_authselect_present.stat.exists

    - name: Set Lockout Time for Failed Password Attempts - Define a fact for control
        already filtered in case filters are used
      ansible.builtin.set_fact:
        pam_module_control: ''

    - name: Set Lockout Time for Failed Password Attempts - Ensure the "unlock_time"
        option from "pam_faillock.so" is not present in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: (.*auth.*pam_faillock.so.*)\bunlock_time\b=?[0-9a-zA-Z]*(.*)
        replace: \1\2
      register: result_pam_option_removal

    - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
        are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present.stat.exists
      - result_pam_option_removal is changed
    when:
    - result_pam_file_present.stat.exists
  when:
  - '"pam" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.7
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_unlock_time
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Lockout Time for Failed Password Attempts - Ensure the pam_faillock.so
    unlock_time parameter in PAM files
  block:

  - name: Set Lockout Time for Failed Password Attempts - Check if pam_faillock.so
      unlock_time parameter is already enabled in pam files
    ansible.builtin.lineinfile:
      path: /etc/pam.d/system-auth
      regexp: .*auth.*pam_faillock\.so (preauth|authfail).*unlock_time
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_faillock_unlock_time_parameter_is_present

  - name: Set Lockout Time for Failed Password Attempts - Ensure the inclusion of
      pam_faillock.so preauth unlock_time parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
      line: \1required\3 unlock_time={{ var_accounts_passwords_pam_faillock_unlock_time
        }}
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_unlock_time_parameter_is_present.found == 0

  - name: Set Lockout Time for Failed Password Attempts - Ensure the inclusion of
      pam_faillock.so authfail unlock_time parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
      line: \1required\3 unlock_time={{ var_accounts_passwords_pam_faillock_unlock_time
        }}
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_unlock_time_parameter_is_present.found == 0

  - name: Set Lockout Time for Failed Password Attempts - Ensure the desired value
      for pam_faillock.so preauth unlock_time parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)(unlock_time)=[0-9]+(.*)
      line: \1required\3\4={{ var_accounts_passwords_pam_faillock_unlock_time }}\5
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_unlock_time_parameter_is_present.found > 0

  - name: Set Lockout Time for Failed Password Attempts - Ensure the desired value
      for pam_faillock.so authfail unlock_time parameter in auth section
    ansible.builtin.lineinfile:
      path: '{{ item }}'
      backrefs: true
      regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)(unlock_time)=[0-9]+(.*)
      line: \1required\3\4={{ var_accounts_passwords_pam_faillock_unlock_time }}\5
      state: present
    loop:
    - /etc/pam.d/system-auth
    - /etc/pam.d/password-auth
    when:
    - result_pam_faillock_unlock_time_parameter_is_present.found > 0
  when:
  - '"pam" in ansible_facts.packages'
  - not result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - NIST-800-171-3.1.8
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-8.1.7
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.4
  - accounts_passwords_pam_faillock_unlock_time
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Group Set Password Quality Requirements Group contains 1 group and 10 rules

[ref] The default pam_pwquality PAM module provides strength checking for passwords. It performs a number of checks, such as making sure passwords are not similar to dictionary words, are of at least a certain length, are not the previous password reversed, and are not simply a change of case from the previous password. It can also require passwords to be in certain character classes. The pam_pwquality module is the preferred way of configuring password requirements.

The man pages pam_pwquality(8) provide information on the capabilities and configuration of each.

Group Set Password Quality Requirements with pam_pwquality Group contains 10 rules

[ref] The pam_pwquality PAM module can be configured to meet requirements for a variety of policies.

For example, to configure pam_pwquality to require at least one uppercase character, lowercase character, digit, and other (special) character, make sure that pam_pwquality exists in /etc/pam.d/system-auth:

password    requisite     pam_pwquality.so try_first_pass local_users_only retry=3 authtok_type=

If no such line exists, add one as the first line of the password section in /etc/pam.d/system-auth. Next, modify the settings in /etc/security/pwquality.conf to match the following:

difok = 4
minlen = 14
dcredit = -1
ucredit = -1
lcredit = -1
ocredit = -1
maxrepeat = 3

The arguments can be modified to ensure compliance with your organization's security policy. Discussion of each parameter follows.

Rule Ensure PAM Enforces Password Requirements - Minimum Digit Characters [ref]

The pam_pwquality module's dcredit parameter controls requirements for usage of digits in a password. When set to a negative number, any password will be required to contain that many digits. When set to a positive number, pam_pwquality will grant +1 additional length credit for each digit. Modify the dcredit setting in /etc/security/pwquality.conf to require the use of a digit in passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.

Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_dcredit

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
ospp	FMT_SMF_EXT.1
pcidss	Req-8.2.3
os-srg	SRG-OS-000071-GPOS-00039
anssi	R31
pcidss4	8.3.6, 8.3

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_dcredit='-1'








# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^dcredit")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_dcredit"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^dcredit\\>" "/etc/security/pwquality.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^dcredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
    if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.6
  - accounts_password_pam_dcredit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_password_pam_dcredit # promote to variable
  set_fact:
    var_password_pam_dcredit: !!str -1
  tags:
    - always

- name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Ensure
    PAM variable dcredit is set accordingly
  ansible.builtin.lineinfile:
    create: true
    dest: /etc/security/pwquality.conf
    regexp: ^#?\s*dcredit
    line: dcredit = {{ var_password_pam_dcredit }}
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.6
  - accounts_password_pam_dcredit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure PAM Enforces Password Requirements - Minimum Different Characters [ref]

The pam_pwquality module's difok parameter sets the number of characters in a password that must not be present in and old password during a password change.

Modify the difok setting in /etc/security/pwquality.conf to equal 8 to require differing characters when changing passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute–force attacks.

Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.

Requiring a minimum number of different characters during password changes ensures that newly changed passwords should not resemble previously compromised ones. Note that passwords which are changed on compromised systems will still be compromised, however.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_difok

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.1.1
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(b), CM-6(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000072-GPOS-00040

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_difok='8'








# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^difok")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_difok"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^difok\\>" "/etc/security/pwquality.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^difok\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
    if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(b)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_difok
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_password_pam_difok # promote to variable
  set_fact:
    var_password_pam_difok: !!str 8
  tags:
    - always

- name: Ensure PAM Enforces Password Requirements - Minimum Different Characters -
    Ensure PAM variable difok is set accordingly
  ansible.builtin.lineinfile:
    create: true
    dest: /etc/security/pwquality.conf
    regexp: ^#?\s*difok
    line: difok = {{ var_password_pam_difok }}
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(b)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_difok
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters [ref]

The pam_pwquality module's lcredit parameter controls requirements for usage of lowercase letters in a password. When set to a negative number, any password will be required to contain that many lowercase characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each lowercase character. Modify the lcredit setting in /etc/security/pwquality.conf to require the use of a lowercase character in passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possble combinations that need to be tested before the password is compromised. Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_lcredit

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
ospp	FMT_SMF_EXT.1
pcidss	Req-8.2.3
os-srg	SRG-OS-000070-GPOS-00038
anssi	R31
pcidss4	8.3.6, 8.3

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_lcredit='-1'








# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^lcredit")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_lcredit"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^lcredit\\>" "/etc/security/pwquality.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^lcredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
    if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.6
  - accounts_password_pam_lcredit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_password_pam_lcredit # promote to variable
  set_fact:
    var_password_pam_lcredit: !!str -1
  tags:
    - always

- name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters -
    Ensure PAM variable lcredit is set accordingly
  ansible.builtin.lineinfile:
    create: true
    dest: /etc/security/pwquality.conf
    regexp: ^#?\s*lcredit
    line: lcredit = {{ var_password_pam_lcredit }}
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.6
  - accounts_password_pam_lcredit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating Characters from Same Character Class [ref]

The pam_pwquality module's maxclassrepeat parameter controls requirements for consecutive repeating characters from the same character class. When set to a positive number, it will reject passwords which contain more than that number of consecutive characters from the same character class. Modify the maxclassrepeat setting in /etc/security/pwquality.conf to equal 4 to prevent a run of (4 + 1) or more identical characters.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_maxclassrepeat

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000072-GPOS-00040, SRG-OS-000730-GPOS-00190

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_maxclassrepeat='4'








# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^maxclassrepeat")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_maxclassrepeat"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^maxclassrepeat\\>" "/etc/security/pwquality.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^maxclassrepeat\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
    if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_maxclassrepeat
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_password_pam_maxclassrepeat # promote to variable
  set_fact:
    var_password_pam_maxclassrepeat: !!str 4
  tags:
    - always

- name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
    Characters from Same Character Class - Ensure PAM variable maxclassrepeat is set
    accordingly
  ansible.builtin.lineinfile:
    create: true
    dest: /etc/security/pwquality.conf
    regexp: ^#?\s*maxclassrepeat
    line: maxclassrepeat = {{ var_password_pam_maxclassrepeat }}
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_maxclassrepeat
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Set Password Maximum Consecutive Repeating Characters [ref]

The pam_pwquality module's maxrepeat parameter controls requirements for consecutive repeating characters. When set to a positive number, it will reject passwords which contain more than that number of consecutive characters. Modify the maxrepeat setting in /etc/security/pwquality.conf to equal 3 to prevent a run of (3 + 1) or more identical characters.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.

Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.

Passwords with excessive repeating characters may be more vulnerable to password-guessing attacks.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_maxrepeat

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), CM-6(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000072-GPOS-00040

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_maxrepeat='3'








# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^maxrepeat")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_maxrepeat"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^maxrepeat\\>" "/etc/security/pwquality.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^maxrepeat\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
    if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_maxrepeat
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_password_pam_maxrepeat # promote to variable
  set_fact:
    var_password_pam_maxrepeat: !!str 3
  tags:
    - always

- name: Set Password Maximum Consecutive Repeating Characters - Ensure PAM variable
    maxrepeat is set accordingly
  ansible.builtin.lineinfile:
    create: true
    dest: /etc/security/pwquality.conf
    regexp: ^#?\s*maxrepeat
    line: maxrepeat = {{ var_password_pam_maxrepeat }}
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_maxrepeat
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure PAM Enforces Password Requirements - Minimum Different Categories [ref]

The pam_pwquality module's minclass parameter controls requirements for usage of different character classes, or types, of character that must exist in a password before it is considered valid. For example, setting this value to three (3) requires that any password must have characters from at least three different categories in order to be approved. The default value is zero (0), meaning there are no required classes. There are four categories available:

* Upper-case characters
* Lower-case characters
* Digits
* Special characters (for example, punctuation)

Modify the minclass setting in /etc/security/pwquality.conf entry to require 4 differing categories of characters when changing passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.

Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.

Requiring a minimum number of character categories makes password guessing attacks more difficult by ensuring a larger search space.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_minclass

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000072-GPOS-00040
anssi	R68

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_minclass='4'








# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^minclass")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_minclass"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^minclass\\>" "/etc/security/pwquality.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^minclass\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
    if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_minclass
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_password_pam_minclass # promote to variable
  set_fact:
    var_password_pam_minclass: !!str 4
  tags:
    - always

- name: Ensure PAM Enforces Password Requirements - Minimum Different Categories -
    Ensure PAM variable minclass is set accordingly
  ansible.builtin.lineinfile:
    create: true
    dest: /etc/security/pwquality.conf
    regexp: ^#?\s*minclass
    line: minclass = {{ var_password_pam_minclass }}
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_minclass
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure PAM Enforces Password Requirements - Minimum Length [ref]

The pam_pwquality module's minlen parameter controls requirements for minimum characters required in a password. Add

minlen=15

after pam_pwquality to set minimum password length requirements.

Rationale:

The shorter the password, the lower the number of possible combinations that need to be tested before the password is compromised.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_minlen

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.1.1
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
ospp	FMT_SMF_EXT.1
pcidss	Req-8.2.3
os-srg	SRG-OS-000078-GPOS-00046
anssi	R31, R68
pcidss4	8.3.6, 8.3

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_minlen='15'








# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^minlen")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_minlen"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^minlen\\>" "/etc/security/pwquality.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^minlen\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
    if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.6
  - accounts_password_pam_minlen
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_password_pam_minlen # promote to variable
  set_fact:
    var_password_pam_minlen: !!str 15
  tags:
    - always

- name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure PAM variable
    minlen is set accordingly
  ansible.builtin.lineinfile:
    create: true
    dest: /etc/security/pwquality.conf
    regexp: ^#?\s*minlen
    line: minlen = {{ var_password_pam_minlen }}
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.6
  - accounts_password_pam_minlen
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure PAM Enforces Password Requirements - Minimum Special Characters [ref]

The pam_pwquality module's ocredit= parameter controls requirements for usage of special (or "other") characters in a password. When set to a negative number, any password will be required to contain that many special characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each special character. Modify the ocredit setting in /etc/security/pwquality.conf to equal -1 to require use of a special character in passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.

Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_ocredit

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
ospp	FMT_SMF_EXT.1
os-srg	SRG-OS-000266-GPOS-00101
anssi	R31

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_ocredit='-1'








# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^ocredit")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_ocredit"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^ocredit\\>" "/etc/security/pwquality.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^ocredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
    if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_ocredit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_password_pam_ocredit # promote to variable
  set_fact:
    var_password_pam_ocredit: !!str -1
  tags:
    - always

- name: Ensure PAM Enforces Password Requirements - Minimum Special Characters - Ensure
    PAM variable ocredit is set accordingly
  ansible.builtin.lineinfile:
    create: true
    dest: /etc/security/pwquality.conf
    regexp: ^#?\s*ocredit
    line: ocredit = {{ var_password_pam_ocredit }}
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - accounts_password_pam_ocredit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted Per-Session [ref]

To configure the number of retry prompts that are permitted per-session: Edit the pam_pwquality.so statement in /etc/pam.d/system-auth to show

retry=3

, or a lower value if site policy is more restrictive. The DoD requirement is a maximum of 3 prompts per session.

Rationale:

Setting the password retry prompts that are permitted on a per-session basis to a low value requires some software, such as SSH, to re-connect. This can slow down and draw additional attention to some types of password-guessing attacks. Note that this is different from account lockout, which is provided by the pam_faillock module.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_retry

References:

cis-csc	1, 11, 12, 15, 16, 3, 5, 9
cjis	5.5.3
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-6(a), AC-7(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7, PR.IP-1
os-srg	SRG-OS-000069-GPOS-00037, SRG-OS-000480-GPOS-00227
anssi	R68

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_retry='3'



	
		if [ -e "/etc/pam.d/system-auth" ] ; then
    PAM_FILE_PATH="/etc/pam.d/system-auth"
    if [ -f /usr/bin/authselect ]; then
        
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi

        CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
        # If not already in use, a custom profile is created preserving the enabled features.
        if [[ ! $CURRENT_PROFILE == custom/* ]]; then
            ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
            authselect create-profile hardening -b $CURRENT_PROFILE
            CURRENT_PROFILE="custom/hardening"
            
            authselect apply-changes -b --backup=before-hardening-custom-profile
            authselect select $CURRENT_PROFILE
            for feature in $ENABLED_FEATURES; do
                authselect enable-feature $feature;
            done
            
            authselect apply-changes -b --backup=after-hardening-custom-profile
        fi
        PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
        PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

        authselect apply-changes -b
    fi
    

        if ! grep -qP "^\s*password\s+requisite\s+pam_pwquality.so\s*.*" "$PAM_FILE_PATH"; then
            # Line matching group + control + module was not found. Check group + module.
            if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwquality.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                # The control is updated only if one single line matches.
                sed -i -E --follow-symlinks "s/^(\s*password\s+).*(\bpam_pwquality.so.*)/\1requisite \2/" "$PAM_FILE_PATH"
            else
                LAST_MATCH_LINE=$(grep -nP "^\s*account" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
                if [ ! -z $LAST_MATCH_LINE ]; then
                    sed -i --follow-symlinks $LAST_MATCH_LINE" a password     requisite    pam_pwquality.so" "$PAM_FILE_PATH"
                else
                    echo "password    requisite    pam_pwquality.so" >> "$PAM_FILE_PATH"
                fi
            fi
        fi
        # Check the option
        if ! grep -qP "^\s*password\s+requisite\s+pam_pwquality.so\s*.*\sretry\b" "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks "/\s*password\s+requisite\s+pam_pwquality.so.*/ s/$/ retry=$var_password_pam_retry/" "$PAM_FILE_PATH"
        else
            sed -i -E --follow-symlinks "s/(\s*password\s+requisite\s+pam_pwquality.so\s+.*)(retry=)[[:alnum:]]+\s*(.*)/\1\2$var_password_pam_retry \3/" "$PAM_FILE_PATH"
        fi
    if [ -f /usr/bin/authselect ]; then
        
        authselect apply-changes -b
    fi
else
    echo "/etc/pam.d/system-auth was not found" >&2
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.3
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - accounts_password_pam_retry
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value var_password_pam_retry # promote to variable
  set_fact:
    var_password_pam_retry: !!str 3
  tags:
    - always

- name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
    Per-Session - Define a fact for control already filtered in case filters are used
  ansible.builtin.set_fact:
    pam_module_control: requisite
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - accounts_password_pam_retry
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
    Per-Session - Check if expected PAM module line is present in /etc/pam.d/system-auth
  ansible.builtin.lineinfile:
    path: /etc/pam.d/system-auth
    regexp: ^\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_pwquality.so\s*.*
    state: absent
  check_mode: true
  changed_when: false
  register: result_pam_line_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - accounts_password_pam_retry
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
    Per-Session - Include or update the PAM module line in /etc/pam.d/system-auth
  block:

  - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts
      Permitted Per-Session - Check if required PAM module line is present in /etc/pam.d/system-auth
      with different control
    ansible.builtin.lineinfile:
      path: /etc/pam.d/system-auth
      regexp: ^\s*password\s+.*\s+pam_pwquality.so\s*
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_line_other_control_present

  - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts
      Permitted Per-Session - Ensure the correct control for the required PAM module
      line in /etc/pam.d/system-auth
    ansible.builtin.replace:
      dest: /etc/pam.d/system-auth
      regexp: ^(\s*password\s+).*(\bpam_pwquality.so.*)
      replace: \1{{ pam_module_control }} \2
    register: result_pam_module_edit
    when:
    - result_pam_line_other_control_present.found == 1

  - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts
      Permitted Per-Session - Ensure the required PAM module line is included in /etc/pam.d/system-auth
    ansible.builtin.lineinfile:
      dest: /etc/pam.d/system-auth
      insertafter: ^\s*account
      line: password    {{ pam_module_control }}    pam_pwquality.so
    register: result_pam_module_add
    when:
    - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
      > 1

  - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts
      Permitted Per-Session - Ensure authselect changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_present is defined
    - result_authselect_present.stat.exists
    - |-
      (result_pam_module_add is defined and result_pam_module_add.changed)
       or (result_pam_module_edit is defined and result_pam_module_edit.changed)
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_line_present.found is defined
  - result_pam_line_present.found == 0
  tags:
  - CJIS-5.5.3
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - accounts_password_pam_retry
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
    Per-Session - Define a fact for control already filtered in case filters are used
  ansible.builtin.set_fact:
    pam_module_control: requisite
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - accounts_password_pam_retry
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
    Per-Session - Check if the required PAM module option is present in /etc/pam.d/system-auth
  ansible.builtin.lineinfile:
    path: /etc/pam.d/system-auth
    regexp: ^\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_pwquality.so\s*.*\sretry\b
    state: absent
  check_mode: true
  changed_when: false
  register: result_pam_module_accounts_password_pam_retry_option_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - accounts_password_pam_retry
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
    Per-Session - Ensure the "retry" PAM option for "pam_pwquality.so" is included
    in /etc/pam.d/system-auth
  ansible.builtin.lineinfile:
    path: /etc/pam.d/system-auth
    backrefs: true
    regexp: ^(\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_pwquality.so.*)
    line: \1 retry={{ var_password_pam_retry }}
    state: present
  register: result_pam_accounts_password_pam_retry_add
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_module_accounts_password_pam_retry_option_present.found == 0
  tags:
  - CJIS-5.5.3
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - accounts_password_pam_retry
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
    Per-Session - Ensure the required value for "retry" PAM option from "pam_pwquality.so"
    in /etc/pam.d/system-auth
  ansible.builtin.lineinfile:
    path: /etc/pam.d/system-auth
    backrefs: true
    regexp: ^(\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_pwquality.so\s+.*)(retry)=[0-9a-zA-Z]+\s*(.*)
    line: \1\2={{ var_password_pam_retry }} \3
  register: result_pam_accounts_password_pam_retry_edit
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_module_accounts_password_pam_retry_option_present.found > 0
  tags:
  - CJIS-5.5.3
  - NIST-800-53-AC-7(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(4)
  - accounts_password_pam_retry
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed

Rule Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters [ref]

The pam_pwquality module's ucredit= parameter controls requirements for usage of uppercase letters in a password. When set to a negative number, any password will be required to contain that many uppercase characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each uppercase character. Modify the ucredit setting in /etc/security/pwquality.conf to require the use of an uppercase character in passwords.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_pam_ucredit

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
ospp	FMT_SMF_EXT.1
pcidss	Req-8.2.3
os-srg	SRG-OS-000069-GPOS-00037, SRG-OS-000070-GPOS-00038
anssi	R31

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_pam_ucredit='-1'








# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^ucredit")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_ucredit"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^ucredit\\>" "/etc/security/pwquality.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^ucredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
else
    if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - accounts_password_pam_ucredit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_password_pam_ucredit # promote to variable
  set_fact:
    var_password_pam_ucredit: !!str -1
  tags:
    - always

- name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters -
    Ensure PAM variable ucredit is set accordingly
  ansible.builtin.lineinfile:
    create: true
    dest: /etc/security/pwquality.conf
    regexp: ^#?\s*ucredit
    line: ucredit = {{ var_password_pam_ucredit }}
  when: '"pam" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(4)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - accounts_password_pam_ucredit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Group Set Password Hashing Algorithm Group contains 4 rules

[ref] The system's default algorithm for storing password hashes in /etc/shadow is SHA-512. This can be configured in several locations.

Rule Set Password Hashing Algorithm in /etc/libuser.conf [ref]

In /etc/libuser.conf, add or correct the following line in its [defaults] section to ensure the system will use the sha512 algorithm for password hashing:

crypt_style = sha512

Rationale:

Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm are no more protected than if they are kept in plain text.

This setting ensures user and group account administration utilities are configured to store only encrypted representations of passwords. Additionally, the crypt_style configuration option in /etc/libuser.conf ensures the use of a strong hashing algorithm that makes password cracking attacks more difficult.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_libuserconf

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.2
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.13.11
disa	CCI-004062
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0418, 1055, 1402
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(c), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.2.1
os-srg	SRG-OS-000073-GPOS-00041
pcidss4	8.3.2, 8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q libuser; then

var_password_hashing_algorithm_pam='sha512'

LIBUSER_CONF="/etc/libuser.conf"
CRYPT_STYLE_REGEX='[[:space:]]*\[defaults](.*(\n)+)+?[[:space:]]*crypt_style[[:space:]]*'

# Try find crypt_style in [defaults] section. If it is here, then change algorithm to sha512.
# If it isn't here, then add it to [defaults] section.
if grep -qzosP $CRYPT_STYLE_REGEX $LIBUSER_CONF ; then
        sed -i "s/\(crypt_style[[:space:]]*=[[:space:]]*\).*/\1$var_password_hashing_algorithm_pam/g" $LIBUSER_CONF
elif grep -qs "\[defaults]" $LIBUSER_CONF ; then
        sed -i "/[[:space:]]*\[defaults]/a crypt_style = $var_password_hashing_algorithm_pam" $LIBUSER_CONF
else
        echo -e "[defaults]\ncrypt_style = $var_password_hashing_algorithm_pam" >> $LIBUSER_CONF
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.2
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - set_password_hashing_algorithm_libuserconf
- name: XCCDF Value var_password_hashing_algorithm_pam # promote to variable
  set_fact:
    var_password_hashing_algorithm_pam: !!str sha512
  tags:
    - always

- name: Set Password Hashing Algorithm in /etc/libuser.conf - Set Password Hashing
    Algorithm in /etc/libuser.conf
  ansible.builtin.lineinfile:
    dest: /etc/libuser.conf
    insertafter: ^\s*\[defaults]
    regexp: ^#?crypt_style
    line: crypt_style = {{ var_password_hashing_algorithm_pam }}
    state: present
    create: true
  when: '"libuser" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.2
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - set_password_hashing_algorithm_libuserconf

Rule Set Password Hashing Algorithm in /etc/login.defs [ref]

In /etc/login.defs, add or update the following line to ensure the system will use SHA512 as the hashing algorithm:

ENCRYPT_METHOD SHA512

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_logindefs

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.2
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.13.11
disa	CCI-004062
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0418, 1055, 1402
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(c), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.2.1
os-srg	SRG-OS-000073-GPOS-00041
pcidss4	8.3.2, 8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then

var_password_hashing_algorithm='SHA512'


# Allow multiple algorithms, but choose the first one for remediation
#
var_password_hashing_algorithm="$(echo $var_password_hashing_algorithm | cut -d \| -f 1)"

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^ENCRYPT_METHOD")

# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_password_hashing_algorithm"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^ENCRYPT_METHOD\\>" "/etc/login.defs"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^ENCRYPT_METHOD\\>.*/$escaped_formatted_output/gi" "/etc/login.defs"
else
    if [[ -s "/etc/login.defs" ]] && [[ -n "$(tail -c 1 -- "/etc/login.defs" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/login.defs"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/login.defs"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.2
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - set_password_hashing_algorithm_logindefs
- name: XCCDF Value var_password_hashing_algorithm # promote to variable
  set_fact:
    var_password_hashing_algorithm: !!str SHA512
  tags:
    - always

- name: Set Password Hashing Algorithm in /etc/login.defs
  lineinfile:
    dest: /etc/login.defs
    regexp: ^#?ENCRYPT_METHOD
    line: ENCRYPT_METHOD {{ var_password_hashing_algorithm.split('|')[0] }}
    state: present
    create: true
  when: '"shadow-utils" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.2
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - set_password_hashing_algorithm_logindefs

Rule Set PAM''s Password Hashing Algorithm - password-auth [ref]

The PAM system service can be configured to only store encrypted representations of passwords. In /etc/pam.d/password-auth, the password section of the file controls which PAM modules to execute during a password change. Set the pam_unix.so module in the password section to include the option sha512 and no other hashing algorithms as shown below:

password    sufficient    pam_unix.so sha512
          other arguments...

This will help ensure that new passwords for local users will be stored using the sha512 algorithm.

Warning: The hashing algorithms to be used with pam_unix.so are defined with independent module options. There are at least 7 possible algorithms and likely more algorithms will be introduced along the time. Due the the number of options and its possible combinations, the use of multiple hashing algorithm options may bring unexpected behaviors to the system. For this reason the check will pass only when one hashing algorithm option is defined and is aligned to the "var_password_hashing_algorithm_pam" variable. The remediation will ensure the correct option and remove any other extra hashing algorithm option.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_passwordauth

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.2
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.13.11
disa	CCI-004062
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0418, 1055, 1402
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(c), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.2.1
os-srg	SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_hashing_algorithm_pam='sha512'

PAM_FILE_PATH="/etc/pam.d/password-auth"

if [ -e "$PAM_FILE_PATH" ] ; then
    PAM_FILE_PATH="$PAM_FILE_PATH"
    if [ -f /usr/bin/authselect ]; then
        
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi

        CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
        # If not already in use, a custom profile is created preserving the enabled features.
        if [[ ! $CURRENT_PROFILE == custom/* ]]; then
            ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
            authselect create-profile hardening -b $CURRENT_PROFILE
            CURRENT_PROFILE="custom/hardening"
            
            authselect apply-changes -b --backup=before-hardening-custom-profile
            authselect select $CURRENT_PROFILE
            for feature in $ENABLED_FEATURES; do
                authselect enable-feature $feature;
            done
            
            authselect apply-changes -b --backup=after-hardening-custom-profile
        fi
        PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
        PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

        authselect apply-changes -b
    fi
    

        if ! grep -qP "^\s*password\s+sufficient\s+pam_unix.so\s*.*" "$PAM_FILE_PATH"; then
            # Line matching group + control + module was not found. Check group + module.
            if [ "$(grep -cP '^\s*password\s+.*\s+pam_unix.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                # The control is updated only if one single line matches.
                sed -i -E --follow-symlinks "s/^(\s*password\s+).*(\bpam_unix.so.*)/\1sufficient \2/" "$PAM_FILE_PATH"
            else
                echo "password    sufficient    pam_unix.so" >> "$PAM_FILE_PATH"
            fi
        fi
        # Check the option
        if ! grep -qP "^\s*password\s+sufficient\s+pam_unix.so\s*.*\s$var_password_hashing_algorithm_pam\b" "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks "/\s*password\s+sufficient\s+pam_unix.so.*/ s/$/ $var_password_hashing_algorithm_pam/" "$PAM_FILE_PATH"
        fi
    if [ -f /usr/bin/authselect ]; then
        
        authselect apply-changes -b
    fi
else
    echo "$PAM_FILE_PATH was not found" >&2
fi

# Ensure only the correct hashing algorithm option is used.
declare -a HASHING_ALGORITHMS_OPTIONS=("sha512" "yescrypt" "gost_yescrypt" "blowfish" "sha256" "md5" "bigcrypt")

for hash_option in "${HASHING_ALGORITHMS_OPTIONS[@]}"; do
  if [ "$hash_option" != "$var_password_hashing_algorithm_pam" ]; then
    if grep -qP "^\s*password\s+.*\s+pam_unix.so\s+.*\b$hash_option\b" "$PAM_FILE_PATH"; then
      if [ -e "$PAM_FILE_PATH" ] ; then
    PAM_FILE_PATH="$PAM_FILE_PATH"
    if [ -f /usr/bin/authselect ]; then
        
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi

        CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
        # If not already in use, a custom profile is created preserving the enabled features.
        if [[ ! $CURRENT_PROFILE == custom/* ]]; then
            ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
            authselect create-profile hardening -b $CURRENT_PROFILE
            CURRENT_PROFILE="custom/hardening"
            
            authselect apply-changes -b --backup=before-hardening-custom-profile
            authselect select $CURRENT_PROFILE
            for feature in $ENABLED_FEATURES; do
                authselect enable-feature $feature;
            done
            
            authselect apply-changes -b --backup=after-hardening-custom-profile
        fi
        PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
        PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

        authselect apply-changes -b
    fi
    
if grep -qP "^\s*password\s+.*\s+pam_unix.so\s.*\b$hash_option\b" "$PAM_FILE_PATH"; then
    sed -i -E --follow-symlinks "s/(.*password.*.*.*pam_unix.so.*)\s$hash_option=?[[:alnum:]]*(.*)/\1\2/g" "$PAM_FILE_PATH"
fi
    if [ -f /usr/bin/authselect ]; then
        
        authselect apply-changes -b
    fi
else
    echo "$PAM_FILE_PATH was not found" >&2
fi
    fi
  fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_passwordauth
- name: XCCDF Value var_password_hashing_algorithm_pam # promote to variable
  set_fact:
    var_password_hashing_algorithm_pam: !!str sha512
  tags:
    - always

- name: Set PAM's Password Hashing Algorithm - password-auth - Check if /etc/pam.d/password-auth
    file is present
  ansible.builtin.stat:
    path: /etc/pam.d/password-auth
  register: result_pam_file_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_passwordauth

- name: Set PAM's Password Hashing Algorithm - password-auth - Check the proper remediation
    for the system
  block:

  - name: Set PAM's Password Hashing Algorithm - password-auth - Define the PAM file
      to be edited as a local fact
    ansible.builtin.set_fact:
      pam_file_path: /etc/pam.d/password-auth

  - name: Set PAM's Password Hashing Algorithm - password-auth - Check if system relies
      on authselect tool
    ansible.builtin.stat:
      path: /usr/bin/authselect
    register: result_authselect_present

  - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure authselect
      custom profile is used if authselect is present
    block:

    - name: Set PAM's Password Hashing Algorithm - password-auth - Check integrity
        of authselect current profile
      ansible.builtin.command:
        cmd: authselect check
      register: result_authselect_check_cmd
      changed_when: false
      failed_when: false

    - name: Set PAM's Password Hashing Algorithm - password-auth - Informative message
        based on the authselect integrity check result
      ansible.builtin.assert:
        that:
        - result_authselect_check_cmd.rc == 0
        fail_msg:
        - authselect integrity check failed. Remediation aborted!
        - This remediation could not be applied because an authselect profile was
          not selected or the selected profile is not intact.
        - It is not recommended to manually edit the PAM files when authselect tool
          is available.
        - In cases where the default authselect profile does not cover a specific
          demand, a custom authselect profile is recommended.
        success_msg:
        - authselect integrity check passed

    - name: Set PAM's Password Hashing Algorithm - password-auth - Get authselect
        current profile
      ansible.builtin.shell:
        cmd: authselect current -r | awk '{ print $1 }'
      register: result_authselect_profile
      changed_when: false
      when:
      - result_authselect_check_cmd is success

    - name: Set PAM's Password Hashing Algorithm - password-auth - Define the current
        authselect profile as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is match("custom/")

    - name: Set PAM's Password Hashing Algorithm - password-auth - Define the new
        authselect custom profile as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: custom/hardening
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - password-auth - Get authselect
        current features to also enable them in the custom profile
      ansible.builtin.shell:
        cmd: authselect current | tail -n+3 | awk '{ print $2 }'
      register: result_authselect_features
      changed_when: false
      when:
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - password-auth - Check if any custom
        profile with the same name was already created
      ansible.builtin.stat:
        path: /etc/authselect/{{ authselect_custom_profile }}
      register: result_authselect_custom_profile_present
      changed_when: false
      when:
      - authselect_current_profile is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - password-auth - Create an authselect
        custom profile based on the current profile
      ansible.builtin.command:
        cmd: authselect create-profile hardening -b {{ authselect_current_profile
          }}
      when:
      - result_authselect_check_cmd is success
      - authselect_current_profile is not match("custom/")
      - not result_authselect_custom_profile_present.stat.exists

    - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure the authselect
        custom profile is selected
      ansible.builtin.command:
        cmd: authselect select {{ authselect_custom_profile }}
      register: result_pam_authselect_select_profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Set PAM's Password Hashing Algorithm - password-auth - Restore the authselect
        features in the custom profile
      ansible.builtin.command:
        cmd: authselect enable-feature {{ item }}
      loop: '{{ result_authselect_features.stdout_lines }}'
      register: result_pam_authselect_restore_features
      when:
      - result_authselect_profile is not skipped
      - result_authselect_features is not skipped
      - result_pam_authselect_select_profile is not skipped

    - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - result_pam_authselect_restore_features is not skipped

    - name: Set PAM's Password Hashing Algorithm - password-auth - Change the PAM
        file to be edited according to the custom authselect profile
      ansible.builtin.set_fact:
        pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
          | basename }}
    when:
    - result_authselect_present.stat.exists

  - name: Set PAM's Password Hashing Algorithm - password-auth - Define a fact for
      control already filtered in case filters are used
    ansible.builtin.set_fact:
      pam_module_control: sufficient

  - name: Set PAM's Password Hashing Algorithm - password-auth - Check if expected
      PAM module line is present in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      regexp: ^\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_unix.so\s*.*
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_line_present

  - name: Set PAM's Password Hashing Algorithm - password-auth - Include or update
      the PAM module line in {{ pam_file_path }}
    block:

    - name: Set PAM's Password Hashing Algorithm - password-auth - Check if required
        PAM module line is present in {{ pam_file_path }} with different control
      ansible.builtin.lineinfile:
        path: '{{ pam_file_path }}'
        regexp: ^\s*password\s+.*\s+pam_unix.so\s*
        state: absent
      check_mode: true
      changed_when: false
      register: result_pam_line_other_control_present

    - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure the correct
        control for the required PAM module line in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: ^(\s*password\s+).*(\bpam_unix.so.*)
        replace: \1{{ pam_module_control }} \2
      register: result_pam_module_edit
      when:
      - result_pam_line_other_control_present.found == 1

    - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure the required
        PAM module line is included in {{ pam_file_path }}
      ansible.builtin.lineinfile:
        dest: '{{ pam_file_path }}'
        line: password    {{ pam_module_control }}    pam_unix.so
      register: result_pam_module_add
      when:
      - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
        > 1

    - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present is defined
      - result_authselect_present.stat.exists
      - |-
        (result_pam_module_add is defined and result_pam_module_add.changed)
         or (result_pam_module_edit is defined and result_pam_module_edit.changed)
    when:
    - result_pam_line_present.found is defined
    - result_pam_line_present.found == 0

  - name: Set PAM's Password Hashing Algorithm - password-auth - Define a fact for
      control already filtered in case filters are used
    ansible.builtin.set_fact:
      pam_module_control: sufficient

  - name: Set PAM's Password Hashing Algorithm - password-auth - Check if the required
      PAM module option is present in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      regexp: ^\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_unix.so\s*.*\s{{
        var_password_hashing_algorithm_pam }}\b
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_module_set_password_hashing_algorithm_passwordauth_option_present

  - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure the "{{ var_password_hashing_algorithm_pam
      }}" PAM option for "pam_unix.so" is included in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      backrefs: true
      regexp: ^(\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_unix.so.*)
      line: \1 {{ var_password_hashing_algorithm_pam }}
      state: present
    register: result_pam_set_password_hashing_algorithm_passwordauth_add
    when:
    - result_pam_module_set_password_hashing_algorithm_passwordauth_option_present.found
      == 0

  - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure authselect
      changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_present.stat.exists
    - |-
      (result_pam_set_password_hashing_algorithm_passwordauth_add is defined and result_pam_set_password_hashing_algorithm_passwordauth_add.changed)
       or (result_pam_set_password_hashing_algorithm_passwordauth_edit is defined and result_pam_set_password_hashing_algorithm_passwordauth_edit.changed)
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_file_present.stat.exists
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_passwordauth

- name: Set PAM's Password Hashing Algorithm - password-auth - Check if /etc/pam.d/password-auth
    File is Present
  ansible.builtin.stat:
    path: /etc/pam.d/password-auth
  register: result_pam_file_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_passwordauth

- name: Set PAM's Password Hashing Algorithm - password-auth - Check The Proper Remediation
    For The System
  block:

  - name: Set PAM's Password Hashing Algorithm - password-auth - Define the PAM file
      to be edited as a local fact
    ansible.builtin.set_fact:
      pam_file_path: /etc/pam.d/password-auth

  - name: Set PAM's Password Hashing Algorithm - password-auth - Check if system relies
      on authselect tool
    ansible.builtin.stat:
      path: /usr/bin/authselect
    register: result_authselect_present

  - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure authselect
      custom profile is used if authselect is present
    block:

    - name: Set PAM's Password Hashing Algorithm - password-auth - Check integrity
        of authselect current profile
      ansible.builtin.command:
        cmd: authselect check
      register: result_authselect_check_cmd
      changed_when: false
      failed_when: false

    - name: Set PAM's Password Hashing Algorithm - password-auth - Informative message
        based on the authselect integrity check result
      ansible.builtin.assert:
        that:
        - result_authselect_check_cmd.rc == 0
        fail_msg:
        - authselect integrity check failed. Remediation aborted!
        - This remediation could not be applied because an authselect profile was
          not selected or the selected profile is not intact.
        - It is not recommended to manually edit the PAM files when authselect tool
          is available.
        - In cases where the default authselect profile does not cover a specific
          demand, a custom authselect profile is recommended.
        success_msg:
        - authselect integrity check passed

    - name: Set PAM's Password Hashing Algorithm - password-auth - Get authselect
        current profile
      ansible.builtin.shell:
        cmd: authselect current -r | awk '{ print $1 }'
      register: result_authselect_profile
      changed_when: false
      when:
      - result_authselect_check_cmd is success

    - name: Set PAM's Password Hashing Algorithm - password-auth - Define the current
        authselect profile as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is match("custom/")

    - name: Set PAM's Password Hashing Algorithm - password-auth - Define the new
        authselect custom profile as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: custom/hardening
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - password-auth - Get authselect
        current features to also enable them in the custom profile
      ansible.builtin.shell:
        cmd: authselect current | tail -n+3 | awk '{ print $2 }'
      register: result_authselect_features
      changed_when: false
      when:
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - password-auth - Check if any custom
        profile with the same name was already created
      ansible.builtin.stat:
        path: /etc/authselect/{{ authselect_custom_profile }}
      register: result_authselect_custom_profile_present
      changed_when: false
      when:
      - authselect_current_profile is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - password-auth - Create an authselect
        custom profile based on the current profile
      ansible.builtin.command:
        cmd: authselect create-profile hardening -b {{ authselect_current_profile
          }}
      when:
      - result_authselect_check_cmd is success
      - authselect_current_profile is not match("custom/")
      - not result_authselect_custom_profile_present.stat.exists

    - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure the authselect
        custom profile is selected
      ansible.builtin.command:
        cmd: authselect select {{ authselect_custom_profile }}
      register: result_pam_authselect_select_profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Set PAM's Password Hashing Algorithm - password-auth - Restore the authselect
        features in the custom profile
      ansible.builtin.command:
        cmd: authselect enable-feature {{ item }}
      loop: '{{ result_authselect_features.stdout_lines }}'
      register: result_pam_authselect_restore_features
      when:
      - result_authselect_profile is not skipped
      - result_authselect_features is not skipped
      - result_pam_authselect_select_profile is not skipped

    - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - result_pam_authselect_restore_features is not skipped

    - name: Set PAM's Password Hashing Algorithm - password-auth - Change the PAM
        file to be edited according to the custom authselect profile
      ansible.builtin.set_fact:
        pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
          | basename }}
    when:
    - result_authselect_present.stat.exists

  - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure That Only
      the Correct Hashing Algorithm Option For pam_unix.so Is Used in /etc/pam.d/password-auth
    ansible.builtin.replace:
      dest: '{{ pam_file_path }}'
      regexp: (^\s*password.*pam_unix\.so.*)\b{{ item }}\b\s*(.*)
      replace: \1\2
    when: item != var_password_hashing_algorithm_pam
    loop:
    - sha512
    - yescrypt
    - gost_yescrypt
    - blowfish
    - sha256
    - md5
    - bigcrypt
    register: result_pam_hashing_options_removal

  - name: Set PAM's Password Hashing Algorithm - password-auth - Ensure authselect
      changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_present.stat.exists
    - result_pam_hashing_options_removal is changed
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_file_present.stat.exists
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_passwordauth

Rule Set PAM''s Password Hashing Algorithm [ref]

The PAM system service can be configured to only store encrypted representations of passwords. In "/etc/pam.d/system-auth", the password section of the file controls which PAM modules to execute during a password change. Set the pam_unix.so module in the password section to include the option sha512 and no other hashing algorithms as shown below:

password    sufficient    pam_unix.so sha512
          other arguments...

This will help ensure that new passwords for local users will be stored using the sha512 algorithm.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_systemauth

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.2
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.13.11
disa	CCI-000196, CCI-000803, CCI-004062
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0418, 1055, 1402
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(c), IA-5(1)(c), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.2.1
os-srg	SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061
anssi	R68
pcidss4	8.3.2, 8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_password_hashing_algorithm_pam='sha512'


PAM_FILE_PATH="/etc/pam.d/system-auth"
CONTROL="sufficient"

if [ -e "$PAM_FILE_PATH" ] ; then
    PAM_FILE_PATH="$PAM_FILE_PATH"
    if [ -f /usr/bin/authselect ]; then
        
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi

        CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
        # If not already in use, a custom profile is created preserving the enabled features.
        if [[ ! $CURRENT_PROFILE == custom/* ]]; then
            ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
            authselect create-profile hardening -b $CURRENT_PROFILE
            CURRENT_PROFILE="custom/hardening"
            
            authselect apply-changes -b --backup=before-hardening-custom-profile
            authselect select $CURRENT_PROFILE
            for feature in $ENABLED_FEATURES; do
                authselect enable-feature $feature;
            done
            
            authselect apply-changes -b --backup=after-hardening-custom-profile
        fi
        PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
        PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

        authselect apply-changes -b
    fi
    

        if ! grep -qP "^\s*password\s+\$CONTROL\s+pam_unix.so\s*.*" "$PAM_FILE_PATH"; then
            # Line matching group + control + module was not found. Check group + module.
            if [ "$(grep -cP '^\s*password\s+.*\s+pam_unix.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                # The control is updated only if one single line matches.
                sed -i -E --follow-symlinks "s/^(\s*password\s+).*(\bpam_unix.so.*)/\1$CONTROL \2/" "$PAM_FILE_PATH"
            else
                echo "password    $CONTROL    pam_unix.so" >> "$PAM_FILE_PATH"
            fi
        fi
        # Check the option
        if ! grep -qP "^\s*password\s+\$CONTROL\s+pam_unix.so\s*.*\s$var_password_hashing_algorithm_pam\b" "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks "/\s*password\s+\$CONTROL\s+pam_unix.so.*/ s/$/ $var_password_hashing_algorithm_pam/" "$PAM_FILE_PATH"
        fi
    if [ -f /usr/bin/authselect ]; then
        
        authselect apply-changes -b
    fi
else
    echo "$PAM_FILE_PATH was not found" >&2
fi

# Ensure only the correct hashing algorithm option is used.
declare -a HASHING_ALGORITHMS_OPTIONS=("sha512" "yescrypt" "gost_yescrypt" "blowfish" "sha256" "md5" "bigcrypt")

for hash_option in "${HASHING_ALGORITHMS_OPTIONS[@]}"; do
  if [ "$hash_option" != "$var_password_hashing_algorithm_pam" ]; then
    if grep -qP "^\s*password\s+.*\s+pam_unix.so\s+.*\b$hash_option\b" "$PAM_FILE_PATH"; then
      if [ -e "$PAM_FILE_PATH" ] ; then
    PAM_FILE_PATH="$PAM_FILE_PATH"
    if [ -f /usr/bin/authselect ]; then
        
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi

        CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
        # If not already in use, a custom profile is created preserving the enabled features.
        if [[ ! $CURRENT_PROFILE == custom/* ]]; then
            ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
            authselect create-profile hardening -b $CURRENT_PROFILE
            CURRENT_PROFILE="custom/hardening"
            
            authselect apply-changes -b --backup=before-hardening-custom-profile
            authselect select $CURRENT_PROFILE
            for feature in $ENABLED_FEATURES; do
                authselect enable-feature $feature;
            done
            
            authselect apply-changes -b --backup=after-hardening-custom-profile
        fi
        PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
        PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

        authselect apply-changes -b
    fi
    
if grep -qP "^\s*password\s+.*\s+pam_unix.so\s.*\b$hash_option\b" "$PAM_FILE_PATH"; then
    sed -i -E --follow-symlinks "s/(.*password.*.*.*pam_unix.so.*)\s$hash_option=?[[:alnum:]]*(.*)/\1\2/g" "$PAM_FILE_PATH"
fi
    if [ -f /usr/bin/authselect ]; then
        
        authselect apply-changes -b
    fi
else
    echo "$PAM_FILE_PATH was not found" >&2
fi
    fi
  fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.2
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_systemauth
- name: XCCDF Value var_password_hashing_algorithm_pam # promote to variable
  set_fact:
    var_password_hashing_algorithm_pam: !!str sha512
  tags:
    - always

- name: Set PAM's Password Hashing Algorithm - Check if /etc/pam.d/system-auth file
    is present
  ansible.builtin.stat:
    path: /etc/pam.d/system-auth
  register: result_pam_file_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.2
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_systemauth

- name: Set PAM's Password Hashing Algorithm - Check the proper remediation for the
    system
  block:

  - name: Set PAM's Password Hashing Algorithm - Define the PAM file to be edited
      as a local fact
    ansible.builtin.set_fact:
      pam_file_path: /etc/pam.d/system-auth

  - name: Set PAM's Password Hashing Algorithm - Check if system relies on authselect
      tool
    ansible.builtin.stat:
      path: /usr/bin/authselect
    register: result_authselect_present

  - name: Set PAM's Password Hashing Algorithm - Ensure authselect custom profile
      is used if authselect is present
    block:

    - name: Set PAM's Password Hashing Algorithm - Check integrity of authselect current
        profile
      ansible.builtin.command:
        cmd: authselect check
      register: result_authselect_check_cmd
      changed_when: false
      failed_when: false

    - name: Set PAM's Password Hashing Algorithm - Informative message based on the
        authselect integrity check result
      ansible.builtin.assert:
        that:
        - result_authselect_check_cmd.rc == 0
        fail_msg:
        - authselect integrity check failed. Remediation aborted!
        - This remediation could not be applied because an authselect profile was
          not selected or the selected profile is not intact.
        - It is not recommended to manually edit the PAM files when authselect tool
          is available.
        - In cases where the default authselect profile does not cover a specific
          demand, a custom authselect profile is recommended.
        success_msg:
        - authselect integrity check passed

    - name: Set PAM's Password Hashing Algorithm - Get authselect current profile
      ansible.builtin.shell:
        cmd: authselect current -r | awk '{ print $1 }'
      register: result_authselect_profile
      changed_when: false
      when:
      - result_authselect_check_cmd is success

    - name: Set PAM's Password Hashing Algorithm - Define the current authselect profile
        as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is match("custom/")

    - name: Set PAM's Password Hashing Algorithm - Define the new authselect custom
        profile as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: custom/hardening
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - Get authselect current features
        to also enable them in the custom profile
      ansible.builtin.shell:
        cmd: authselect current | tail -n+3 | awk '{ print $2 }'
      register: result_authselect_features
      changed_when: false
      when:
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - Check if any custom profile with
        the same name was already created
      ansible.builtin.stat:
        path: /etc/authselect/{{ authselect_custom_profile }}
      register: result_authselect_custom_profile_present
      changed_when: false
      when:
      - authselect_current_profile is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - Create an authselect custom profile
        based on the current profile
      ansible.builtin.command:
        cmd: authselect create-profile hardening -b {{ authselect_current_profile
          }}
      when:
      - result_authselect_check_cmd is success
      - authselect_current_profile is not match("custom/")
      - not result_authselect_custom_profile_present.stat.exists

    - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Set PAM's Password Hashing Algorithm - Ensure the authselect custom profile
        is selected
      ansible.builtin.command:
        cmd: authselect select {{ authselect_custom_profile }}
      register: result_pam_authselect_select_profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Set PAM's Password Hashing Algorithm - Restore the authselect features
        in the custom profile
      ansible.builtin.command:
        cmd: authselect enable-feature {{ item }}
      loop: '{{ result_authselect_features.stdout_lines }}'
      register: result_pam_authselect_restore_features
      when:
      - result_authselect_profile is not skipped
      - result_authselect_features is not skipped
      - result_pam_authselect_select_profile is not skipped

    - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - result_pam_authselect_restore_features is not skipped

    - name: Set PAM's Password Hashing Algorithm - Change the PAM file to be edited
        according to the custom authselect profile
      ansible.builtin.set_fact:
        pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
          | basename }}
    when:
    - result_authselect_present.stat.exists

  - name: Set PAM's Password Hashing Algorithm - Define a fact for control already
      filtered in case filters are used
    ansible.builtin.set_fact:
      pam_module_control: sufficient

  - name: Set PAM's Password Hashing Algorithm - Check if expected PAM module line
      is present in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      regexp: ^\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_unix.so\s*.*
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_line_present

  - name: Set PAM's Password Hashing Algorithm - Include or update the PAM module
      line in {{ pam_file_path }}
    block:

    - name: Set PAM's Password Hashing Algorithm - Check if required PAM module line
        is present in {{ pam_file_path }} with different control
      ansible.builtin.lineinfile:
        path: '{{ pam_file_path }}'
        regexp: ^\s*password\s+.*\s+pam_unix.so\s*
        state: absent
      check_mode: true
      changed_when: false
      register: result_pam_line_other_control_present

    - name: Set PAM's Password Hashing Algorithm - Ensure the correct control for
        the required PAM module line in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: ^(\s*password\s+).*(\bpam_unix.so.*)
        replace: \1{{ pam_module_control }} \2
      register: result_pam_module_edit
      when:
      - result_pam_line_other_control_present.found == 1

    - name: Set PAM's Password Hashing Algorithm - Ensure the required PAM module
        line is included in {{ pam_file_path }}
      ansible.builtin.lineinfile:
        dest: '{{ pam_file_path }}'
        line: password    {{ pam_module_control }}    pam_unix.so
      register: result_pam_module_add
      when:
      - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
        > 1

    - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present is defined
      - result_authselect_present.stat.exists
      - |-
        (result_pam_module_add is defined and result_pam_module_add.changed)
         or (result_pam_module_edit is defined and result_pam_module_edit.changed)
    when:
    - result_pam_line_present.found is defined
    - result_pam_line_present.found == 0

  - name: Set PAM's Password Hashing Algorithm - Define a fact for control already
      filtered in case filters are used
    ansible.builtin.set_fact:
      pam_module_control: sufficient

  - name: Set PAM's Password Hashing Algorithm - Check if the required PAM module
      option is present in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      regexp: ^\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_unix.so\s*.*\s{{
        var_password_hashing_algorithm_pam }}\b
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_module_set_password_hashing_algorithm_systemauth_option_present

  - name: Set PAM's Password Hashing Algorithm - Ensure the "{{ var_password_hashing_algorithm_pam
      }}" PAM option for "pam_unix.so" is included in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      backrefs: true
      regexp: ^(\s*password\s+{{ pam_module_control | regex_escape() }}\s+pam_unix.so.*)
      line: \1 {{ var_password_hashing_algorithm_pam }}
      state: present
    register: result_pam_set_password_hashing_algorithm_systemauth_add
    when:
    - result_pam_module_set_password_hashing_algorithm_systemauth_option_present.found
      == 0

  - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_present.stat.exists
    - |-
      (result_pam_set_password_hashing_algorithm_systemauth_add is defined and result_pam_set_password_hashing_algorithm_systemauth_add.changed)
       or (result_pam_set_password_hashing_algorithm_systemauth_edit is defined and result_pam_set_password_hashing_algorithm_systemauth_edit.changed)
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_file_present.stat.exists
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.2
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_systemauth

- name: Set PAM's Password Hashing Algorithm - Check if /etc/pam.d/system-auth File
    is Present
  ansible.builtin.stat:
    path: /etc/pam.d/system-auth
  register: result_pam_file_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.2
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_systemauth

- name: Set PAM's Password Hashing Algorithm - Check The Proper Remediation For The
    System
  block:

  - name: Set PAM's Password Hashing Algorithm - Define the PAM file to be edited
      as a local fact
    ansible.builtin.set_fact:
      pam_file_path: /etc/pam.d/system-auth

  - name: Set PAM's Password Hashing Algorithm - Check if system relies on authselect
      tool
    ansible.builtin.stat:
      path: /usr/bin/authselect
    register: result_authselect_present

  - name: Set PAM's Password Hashing Algorithm - Ensure authselect custom profile
      is used if authselect is present
    block:

    - name: Set PAM's Password Hashing Algorithm - Check integrity of authselect current
        profile
      ansible.builtin.command:
        cmd: authselect check
      register: result_authselect_check_cmd
      changed_when: false
      failed_when: false

    - name: Set PAM's Password Hashing Algorithm - Informative message based on the
        authselect integrity check result
      ansible.builtin.assert:
        that:
        - result_authselect_check_cmd.rc == 0
        fail_msg:
        - authselect integrity check failed. Remediation aborted!
        - This remediation could not be applied because an authselect profile was
          not selected or the selected profile is not intact.
        - It is not recommended to manually edit the PAM files when authselect tool
          is available.
        - In cases where the default authselect profile does not cover a specific
          demand, a custom authselect profile is recommended.
        success_msg:
        - authselect integrity check passed

    - name: Set PAM's Password Hashing Algorithm - Get authselect current profile
      ansible.builtin.shell:
        cmd: authselect current -r | awk '{ print $1 }'
      register: result_authselect_profile
      changed_when: false
      when:
      - result_authselect_check_cmd is success

    - name: Set PAM's Password Hashing Algorithm - Define the current authselect profile
        as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is match("custom/")

    - name: Set PAM's Password Hashing Algorithm - Define the new authselect custom
        profile as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: custom/hardening
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - Get authselect current features
        to also enable them in the custom profile
      ansible.builtin.shell:
        cmd: authselect current | tail -n+3 | awk '{ print $2 }'
      register: result_authselect_features
      changed_when: false
      when:
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - Check if any custom profile with
        the same name was already created
      ansible.builtin.stat:
        path: /etc/authselect/{{ authselect_custom_profile }}
      register: result_authselect_custom_profile_present
      changed_when: false
      when:
      - authselect_current_profile is not match("custom/")

    - name: Set PAM's Password Hashing Algorithm - Create an authselect custom profile
        based on the current profile
      ansible.builtin.command:
        cmd: authselect create-profile hardening -b {{ authselect_current_profile
          }}
      when:
      - result_authselect_check_cmd is success
      - authselect_current_profile is not match("custom/")
      - not result_authselect_custom_profile_present.stat.exists

    - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Set PAM's Password Hashing Algorithm - Ensure the authselect custom profile
        is selected
      ansible.builtin.command:
        cmd: authselect select {{ authselect_custom_profile }}
      register: result_pam_authselect_select_profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Set PAM's Password Hashing Algorithm - Restore the authselect features
        in the custom profile
      ansible.builtin.command:
        cmd: authselect enable-feature {{ item }}
      loop: '{{ result_authselect_features.stdout_lines }}'
      register: result_pam_authselect_restore_features
      when:
      - result_authselect_profile is not skipped
      - result_authselect_features is not skipped
      - result_pam_authselect_select_profile is not skipped

    - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - result_pam_authselect_restore_features is not skipped

    - name: Set PAM's Password Hashing Algorithm - Change the PAM file to be edited
        according to the custom authselect profile
      ansible.builtin.set_fact:
        pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
          | basename }}
    when:
    - result_authselect_present.stat.exists

  - name: Set PAM's Password Hashing Algorithm - Ensure That Only the Correct Hashing
      Algorithm Option For pam_unix.so Is Used in /etc/pam.d/system-auth
    ansible.builtin.replace:
      dest: '{{ pam_file_path }}'
      regexp: (^\s*password.*pam_unix\.so.*)\b{{ item }}\b\s*(.*)
      replace: \1\2
    when: item != var_password_hashing_algorithm_pam
    loop:
    - sha512
    - yescrypt
    - gost_yescrypt
    - blowfish
    - sha256
    - md5
    - bigcrypt
    register: result_pam_hashing_options_removal

  - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_present.stat.exists
    - result_pam_hashing_options_removal is changed
  when:
  - '"pam" in ansible_facts.packages'
  - result_pam_file_present.stat.exists
  tags:
  - CJIS-5.6.2.2
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.1
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.2
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - set_password_hashing_algorithm_systemauth

Rule Ensure PAM Displays Last Logon/Access Notification [ref]

To configure the system to notify users of last logon/access using pam_lastlog, add or correct the pam_lastlog settings in /etc/pam.d/postlogin to include showfailed option, such as:

session     [default=1]    pam_lastlog.so showfailed

And make sure that the silent option is not set for this specific line.

Warning: authselect contains an authselect feature to easily and properly enable Last Logon notifications with pam_lastlog.so module. If a custom profile was created and used in the system before this authselect feature was available, the new feature can't be used with this custom profile and the remediation will fail. In this case, the custom profile should be recreated or manually updated.

Rationale:

Users need to be aware of activity that occurs regarding their account. Providing users with information regarding the number of unsuccessful attempts that were made to login to their account allows the user to determine if any unauthorized activity has occurred and gives them an opportunity to notify administrators.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_display_login_attempts

References:

cis-csc	1, 12, 15, 16
cjis	5.5.2
cobit5	DSS05.04, DSS05.10, DSS06.10
disa	CCI-000366
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
ism	0582, 0584, 05885, 0586, 0846, 0957
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nist	AC-9, AC-9(1)
nist-csf	PR.AC-7
pcidss	Req-10.2.4
os-srg	SRG-OS-000480-GPOS-00227
pcidss4	10.2.1.4, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

if [ -f /usr/bin/authselect ]; then
    if authselect list-features sssd | grep -q with-silent-lastlog; then
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi
        authselect disable-feature with-silent-lastlog

        authselect apply-changes -b
    else
        
        if ! authselect check; then
        echo "
        authselect integrity check failed. Remediation aborted!
        This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
        It is not recommended to manually edit the PAM files when authselect tool is available.
        In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
        exit 1
        fi

        CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
        # If not already in use, a custom profile is created preserving the enabled features.
        if [[ ! $CURRENT_PROFILE == custom/* ]]; then
            ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
            authselect create-profile hardening -b $CURRENT_PROFILE
            CURRENT_PROFILE="custom/hardening"
            
            authselect apply-changes -b --backup=before-hardening-custom-profile
            authselect select $CURRENT_PROFILE
            for feature in $ENABLED_FEATURES; do
                authselect enable-feature $feature;
            done
            
            authselect apply-changes -b --backup=after-hardening-custom-profile
        fi
        PAM_FILE_NAME=$(basename "/etc/pam.d/postlogin")
        PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

        authselect apply-changes -b
        if [ -e "$PAM_FILE_PATH" ] ; then
            PAM_FILE_PATH="$PAM_FILE_PATH"
            if [ -f /usr/bin/authselect ]; then
                
                if ! authselect check; then
                echo "
                authselect integrity check failed. Remediation aborted!
                This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                It is not recommended to manually edit the PAM files when authselect tool is available.
                In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                exit 1
                fi

                CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                # If not already in use, a custom profile is created preserving the enabled features.
                if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                    ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                    authselect create-profile hardening -b $CURRENT_PROFILE
                    CURRENT_PROFILE="custom/hardening"
                    
                    authselect apply-changes -b --backup=before-hardening-custom-profile
                    authselect select $CURRENT_PROFILE
                    for feature in $ENABLED_FEATURES; do
                        authselect enable-feature $feature;
                    done
                    
                    authselect apply-changes -b --backup=after-hardening-custom-profile
                fi
                PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
                PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                authselect apply-changes -b
            fi
            

                if ! grep -qP "^\s*session\s+\[default=1\]\s+pam_lastlog.so\s*.*" "$PAM_FILE_PATH"; then
                    # Line matching group + control + module was not found. Check group + module.
                    if [ "$(grep -cP '^\s*session\s+.*\s+pam_lastlog.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                        # The control is updated only if one single line matches.
                        sed -i -E --follow-symlinks "s/^(\s*session\s+).*(\bpam_lastlog.so.*)/\1[default=1] \2/" "$PAM_FILE_PATH"
                    else
                        LAST_MATCH_LINE=$(grep -nP "^\s*session\s+.*pam_succeed_if\.so.*" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
                        if [ ! -z $LAST_MATCH_LINE ]; then
                            sed -i --follow-symlinks $LAST_MATCH_LINE" a session     [default=1]    pam_lastlog.so" "$PAM_FILE_PATH"
                        else
                            echo "session    [default=1]    pam_lastlog.so" >> "$PAM_FILE_PATH"
                        fi
                    fi
                fi
                # Check the option
                if ! grep -qP "^\s*session\s+\[default=1\]\s+pam_lastlog.so\s*.*\sshowfailed\b" "$PAM_FILE_PATH"; then
                    sed -i -E --follow-symlinks "/\s*session\s+\[default=1\]\s+pam_lastlog.so.*/ s/$/ showfailed/" "$PAM_FILE_PATH"
                fi
            if [ -f /usr/bin/authselect ]; then
                
                authselect apply-changes -b
            fi
        else
            echo "$PAM_FILE_PATH was not found" >&2
        fi
        if [ -e "$PAM_FILE_PATH" ] ; then
            PAM_FILE_PATH="$PAM_FILE_PATH"
            if [ -f /usr/bin/authselect ]; then
                
                if ! authselect check; then
                echo "
                authselect integrity check failed. Remediation aborted!
                This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                It is not recommended to manually edit the PAM files when authselect tool is available.
                In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                exit 1
                fi

                CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                # If not already in use, a custom profile is created preserving the enabled features.
                if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                    ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                    authselect create-profile hardening -b $CURRENT_PROFILE
                    CURRENT_PROFILE="custom/hardening"
                    
                    authselect apply-changes -b --backup=before-hardening-custom-profile
                    authselect select $CURRENT_PROFILE
                    for feature in $ENABLED_FEATURES; do
                        authselect enable-feature $feature;
                    done
                    
                    authselect apply-changes -b --backup=after-hardening-custom-profile
                fi
                PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
                PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                authselect apply-changes -b
            fi
            
        if grep -qP "^\s*session\s+[default=1]\s+pam_lastlog.so\s.*\bsilent\b" "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks "s/(.*session.*[default=1].*pam_lastlog.so.*)\ssilent=?[[:alnum:]]*(.*)/\1\2/g" "$PAM_FILE_PATH"
        fi
            if [ -f /usr/bin/authselect ]; then
                
                authselect apply-changes -b
            fi
        else
            echo "$PAM_FILE_PATH was not found" >&2
        fi
    fi
else
    if [ -e "/etc/pam.d/postlogin" ] ; then
            PAM_FILE_PATH="/etc/pam.d/postlogin"
            if [ -f /usr/bin/authselect ]; then
                
                if ! authselect check; then
                echo "
                authselect integrity check failed. Remediation aborted!
                This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                It is not recommended to manually edit the PAM files when authselect tool is available.
                In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                exit 1
                fi

                CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                # If not already in use, a custom profile is created preserving the enabled features.
                if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                    ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                    authselect create-profile hardening -b $CURRENT_PROFILE
                    CURRENT_PROFILE="custom/hardening"
                    
                    authselect apply-changes -b --backup=before-hardening-custom-profile
                    authselect select $CURRENT_PROFILE
                    for feature in $ENABLED_FEATURES; do
                        authselect enable-feature $feature;
                    done
                    
                    authselect apply-changes -b --backup=after-hardening-custom-profile
                fi
                PAM_FILE_NAME=$(basename "/etc/pam.d/postlogin")
                PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                authselect apply-changes -b
            fi
            

                if ! grep -qP "^\s*session\s+\[default=1\]\s+pam_lastlog.so\s*.*" "$PAM_FILE_PATH"; then
                    # Line matching group + control + module was not found. Check group + module.
                    if [ "$(grep -cP '^\s*session\s+.*\s+pam_lastlog.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                        # The control is updated only if one single line matches.
                        sed -i -E --follow-symlinks "s/^(\s*session\s+).*(\bpam_lastlog.so.*)/\1[default=1] \2/" "$PAM_FILE_PATH"
                    else
                        LAST_MATCH_LINE=$(grep -nP "^\s*session\s+.*pam_succeed_if\.so.*" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
                        if [ ! -z $LAST_MATCH_LINE ]; then
                            sed -i --follow-symlinks $LAST_MATCH_LINE" a session     [default=1]    pam_lastlog.so" "$PAM_FILE_PATH"
                        else
                            echo "session    [default=1]    pam_lastlog.so" >> "$PAM_FILE_PATH"
                        fi
                    fi
                fi
                # Check the option
                if ! grep -qP "^\s*session\s+\[default=1\]\s+pam_lastlog.so\s*.*\sshowfailed\b" "$PAM_FILE_PATH"; then
                    sed -i -E --follow-symlinks "/\s*session\s+\[default=1\]\s+pam_lastlog.so.*/ s/$/ showfailed/" "$PAM_FILE_PATH"
                fi
            if [ -f /usr/bin/authselect ]; then
                
                authselect apply-changes -b
            fi
        else
            echo "/etc/pam.d/postlogin was not found" >&2
        fi
    if [ -e "/etc/pam.d/postlogin" ] ; then
            PAM_FILE_PATH="/etc/pam.d/postlogin"
            if [ -f /usr/bin/authselect ]; then
                
                if ! authselect check; then
                echo "
                authselect integrity check failed. Remediation aborted!
                This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                It is not recommended to manually edit the PAM files when authselect tool is available.
                In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                exit 1
                fi

                CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                # If not already in use, a custom profile is created preserving the enabled features.
                if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                    ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                    authselect create-profile hardening -b $CURRENT_PROFILE
                    CURRENT_PROFILE="custom/hardening"
                    
                    authselect apply-changes -b --backup=before-hardening-custom-profile
                    authselect select $CURRENT_PROFILE
                    for feature in $ENABLED_FEATURES; do
                        authselect enable-feature $feature;
                    done
                    
                    authselect apply-changes -b --backup=after-hardening-custom-profile
                fi
                PAM_FILE_NAME=$(basename "/etc/pam.d/postlogin")
                PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                authselect apply-changes -b
            fi
            
        if grep -qP "^\s*session\s+[default=1]\s+pam_lastlog.so\s.*\bsilent\b" "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks "s/(.*session.*[default=1].*pam_lastlog.so.*)\ssilent=?[[:alnum:]]*(.*)/\1\2/g" "$PAM_FILE_PATH"
        fi
            if [ -f /usr/bin/authselect ]; then
                
                authselect apply-changes -b
            fi
        else
            echo "/etc/pam.d/postlogin was not found" >&2
        fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.2
  - NIST-800-53-AC-9
  - NIST-800-53-AC-9(1)
  - PCI-DSS-Req-10.2.4
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.4
  - configure_strategy
  - display_login_attempts
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed

- name: Ensure PAM Displays Last Logon/Access Notification - Check if system relies
    on authselect tool
  ansible.builtin.stat:
    path: /usr/bin/authselect
  register: result_authselect_present
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.2
  - NIST-800-53-AC-9
  - NIST-800-53-AC-9(1)
  - PCI-DSS-Req-10.2.4
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.4
  - configure_strategy
  - display_login_attempts
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed

- name: Ensure PAM Displays Last Logon/Access Notification - Collect the Available
    authselect Features
  ansible.builtin.command:
    cmd: authselect list-features sssd
  register: result_authselect_available_features
  changed_when: false
  when:
  - '"pam" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.2
  - NIST-800-53-AC-9
  - NIST-800-53-AC-9(1)
  - PCI-DSS-Req-10.2.4
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.4
  - configure_strategy
  - display_login_attempts
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed

- name: Ensure PAM Displays Last Logon/Access Notification - Configure pam_lastlog.so
    Using authselect Feature
  block:

  - name: Ensure PAM Displays Last Logon/Access Notification - Check integrity of
      authselect current profile
    ansible.builtin.command:
      cmd: authselect check
    register: result_authselect_check_cmd
    changed_when: false
    failed_when: false

  - name: Ensure PAM Displays Last Logon/Access Notification - Informative message
      based on the authselect integrity check result
    ansible.builtin.assert:
      that:
      - result_authselect_check_cmd.rc == 0
      fail_msg:
      - authselect integrity check failed. Remediation aborted!
      - This remediation could not be applied because an authselect profile was not
        selected or the selected profile is not intact.
      - It is not recommended to manually edit the PAM files when authselect tool
        is available.
      - In cases where the default authselect profile does not cover a specific demand,
        a custom authselect profile is recommended.
      success_msg:
      - authselect integrity check passed

  - name: Ensure PAM Displays Last Logon/Access Notification - Get authselect Features
      Currently Enabled
    ansible.builtin.shell:
      cmd: authselect current | tail -n+3 | awk '{ print $2 }'
    register: result_authselect_features
    changed_when: false
    when:
    - result_authselect_check_cmd is success

  - name: Ensure PAM Displays Last Logon/Access Notification - Ensure "with-silent-lastlog"
      Feature is Disabled Using authselect Tool
    ansible.builtin.command:
      cmd: authselect disable-feature with-silent-lastlog
    register: result_authselect_disable_feature_cmd
    when:
    - result_authselect_check_cmd is success
    - result_authselect_features.stdout is search("with-silent-lastlog")

  - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect changes
      are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_disable_feature_cmd is not skipped
    - result_authselect_disable_feature_cmd is success
  when:
  - '"pam" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  - result_authselect_available_features.stdout is search("with-silent-lastlog")
  tags:
  - CJIS-5.5.2
  - NIST-800-53-AC-9
  - NIST-800-53-AC-9(1)
  - PCI-DSS-Req-10.2.4
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.4
  - configure_strategy
  - display_login_attempts
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed

- name: Ensure PAM Displays Last Logon/Access Notification - Configure pam_lastlog.so
    in appropriate PAM files
  block:

  - name: Ensure PAM Displays Last Logon/Access Notification - Define the PAM file
      to be edited as a local fact
    ansible.builtin.set_fact:
      pam_file_path: /etc/pam.d/postlogin

  - name: Ensure PAM Displays Last Logon/Access Notification - Check if system relies
      on authselect tool
    ansible.builtin.stat:
      path: /usr/bin/authselect
    register: result_authselect_present

  - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect custom
      profile is used if authselect is present
    block:

    - name: Ensure PAM Displays Last Logon/Access Notification - Check integrity of
        authselect current profile
      ansible.builtin.command:
        cmd: authselect check
      register: result_authselect_check_cmd
      changed_when: false
      failed_when: false

    - name: Ensure PAM Displays Last Logon/Access Notification - Informative message
        based on the authselect integrity check result
      ansible.builtin.assert:
        that:
        - result_authselect_check_cmd.rc == 0
        fail_msg:
        - authselect integrity check failed. Remediation aborted!
        - This remediation could not be applied because an authselect profile was
          not selected or the selected profile is not intact.
        - It is not recommended to manually edit the PAM files when authselect tool
          is available.
        - In cases where the default authselect profile does not cover a specific
          demand, a custom authselect profile is recommended.
        success_msg:
        - authselect integrity check passed

    - name: Ensure PAM Displays Last Logon/Access Notification - Get authselect current
        profile
      ansible.builtin.shell:
        cmd: authselect current -r | awk '{ print $1 }'
      register: result_authselect_profile
      changed_when: false
      when:
      - result_authselect_check_cmd is success

    - name: Ensure PAM Displays Last Logon/Access Notification - Define the current
        authselect profile as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is match("custom/")

    - name: Ensure PAM Displays Last Logon/Access Notification - Define the new authselect
        custom profile as a local fact
      ansible.builtin.set_fact:
        authselect_current_profile: '{{ result_authselect_profile.stdout }}'
        authselect_custom_profile: custom/hardening
      when:
      - result_authselect_profile is not skipped
      - result_authselect_profile.stdout is not match("custom/")

    - name: Ensure PAM Displays Last Logon/Access Notification - Get authselect current
        features to also enable them in the custom profile
      ansible.builtin.shell:
        cmd: authselect current | tail -n+3 | awk '{ print $2 }'
      register: result_authselect_features
      changed_when: false
      when:
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")

    - name: Ensure PAM Displays Last Logon/Access Notification - Check if any custom
        profile with the same name was already created
      ansible.builtin.stat:
        path: /etc/authselect/{{ authselect_custom_profile }}
      register: result_authselect_custom_profile_present
      changed_when: false
      when:
      - authselect_current_profile is not match("custom/")

    - name: Ensure PAM Displays Last Logon/Access Notification - Create an authselect
        custom profile based on the current profile
      ansible.builtin.command:
        cmd: authselect create-profile hardening -b {{ authselect_current_profile
          }}
      when:
      - result_authselect_check_cmd is success
      - authselect_current_profile is not match("custom/")
      - not result_authselect_custom_profile_present.stat.exists

    - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the authselect
        custom profile is selected
      ansible.builtin.command:
        cmd: authselect select {{ authselect_custom_profile }}
      register: result_pam_authselect_select_profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - authselect_current_profile is not match("custom/")
      - authselect_custom_profile is not match(authselect_current_profile)

    - name: Ensure PAM Displays Last Logon/Access Notification - Restore the authselect
        features in the custom profile
      ansible.builtin.command:
        cmd: authselect enable-feature {{ item }}
      loop: '{{ result_authselect_features.stdout_lines }}'
      register: result_pam_authselect_restore_features
      when:
      - result_authselect_profile is not skipped
      - result_authselect_features is not skipped
      - result_pam_authselect_select_profile is not skipped

    - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
      when:
      - result_authselect_check_cmd is success
      - result_authselect_profile is not skipped
      - result_pam_authselect_restore_features is not skipped

    - name: Ensure PAM Displays Last Logon/Access Notification - Change the PAM file
        to be edited according to the custom authselect profile
      ansible.builtin.set_fact:
        pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
          | basename }}
    when:
    - result_authselect_present.stat.exists

  - name: Ensure PAM Displays Last Logon/Access Notification - Define a fact for control
      already filtered in case filters are used
    ansible.builtin.set_fact:
      pam_module_control: '[default=1]'

  - name: Ensure PAM Displays Last Logon/Access Notification - Check if expected PAM
      module line is present in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      regexp: ^\s*session\s+{{ pam_module_control | regex_escape() }}\s+pam_lastlog.so\s*.*
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_line_present

  - name: Ensure PAM Displays Last Logon/Access Notification - Include or update the
      PAM module line in {{ pam_file_path }}
    block:

    - name: Ensure PAM Displays Last Logon/Access Notification - Check if required
        PAM module line is present in {{ pam_file_path }} with different control
      ansible.builtin.lineinfile:
        path: '{{ pam_file_path }}'
        regexp: ^\s*session\s+.*\s+pam_lastlog.so\s*
        state: absent
      check_mode: true
      changed_when: false
      register: result_pam_line_other_control_present

    - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the correct
        control for the required PAM module line in {{ pam_file_path }}
      ansible.builtin.replace:
        dest: '{{ pam_file_path }}'
        regexp: ^(\s*session\s+).*(\bpam_lastlog.so.*)
        replace: \1{{ pam_module_control }} \2
      register: result_pam_module_edit
      when:
      - result_pam_line_other_control_present.found == 1

    - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the required
        PAM module line is included in {{ pam_file_path }}
      ansible.builtin.lineinfile:
        dest: '{{ pam_file_path }}'
        insertafter: ^\s*session\s+.*pam_succeed_if\.so.*
        line: session    {{ pam_module_control }}    pam_lastlog.so
      register: result_pam_module_add
      when:
      - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
        > 1

    - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect
        changes are applied
      ansible.builtin.command:
        cmd: authselect apply-changes -b
      when:
      - result_authselect_present is defined
      - result_authselect_present.stat.exists
      - |-
        (result_pam_module_add is defined and result_pam_module_add.changed)
         or (result_pam_module_edit is defined and result_pam_module_edit.changed)
    when:
    - result_pam_line_present.found is defined
    - result_pam_line_present.found == 0

  - name: Ensure PAM Displays Last Logon/Access Notification - Define a fact for control
      already filtered in case filters are used
    ansible.builtin.set_fact:
      pam_module_control: '[default=1]'

  - name: Ensure PAM Displays Last Logon/Access Notification - Check if the required
      PAM module option is present in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      regexp: ^\s*session\s+{{ pam_module_control | regex_escape() }}\s+pam_lastlog.so\s*.*\sshowfailed\b
      state: absent
    check_mode: true
    changed_when: false
    register: result_pam_module_display_login_attempts_option_present

  - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the "showfailed"
      PAM option for "pam_lastlog.so" is included in {{ pam_file_path }}
    ansible.builtin.lineinfile:
      path: '{{ pam_file_path }}'
      backrefs: true
      regexp: ^(\s*session\s+{{ pam_module_control | regex_escape() }}\s+pam_lastlog.so.*)
      line: \1 showfailed
      state: present
    register: result_pam_display_login_attempts_add
    when:
    - result_pam_module_display_login_attempts_option_present.found == 0

  - name: Ensure PAM Displays Last Logon/Access Notification - Define a fact for control
      already filtered in case filters are used
    ansible.builtin.set_fact:
      pam_module_control: '[default=1]'

  - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the "silent"
      option from "pam_lastlog.so" is not present in {{ pam_file_path }}
    ansible.builtin.replace:
      dest: '{{ pam_file_path }}'
      regexp: (.*session.*{{ pam_module_control | regex_escape() }}.*pam_lastlog.so.*)\bsilent\b=?[0-9a-zA-Z]*(.*)
      replace: \1\2
    register: result_pam_option_removal
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.2
  - NIST-800-53-AC-9
  - NIST-800-53-AC-9(1)
  - PCI-DSS-Req-10.2.4
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.4
  - configure_strategy
  - display_login_attempts
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed

Group Protect Physical Console Access Group contains 3 groups and 11 rules

[ref] It is impossible to fully protect a system from an attacker with physical access, so securing the space in which the system is located should be considered a necessary step. However, there are some steps which, if taken, make it more difficult for an attacker to quickly or undetectably modify a system from its console.

Group Configure Screen Locking Group contains 2 groups and 6 rules

[ref] When a user must temporarily leave an account logged-in, screen locking should be employed to prevent passersby from abusing the account. User education and training is particularly important for screen locking to be effective, and policies can be implemented to reinforce this.

Automatic screen locking is only meant as a safeguard for those cases where a user forgot to lock the screen.

Group Configure Console Screen Locking Group contains 1 rule

[ref] A console screen locking mechanism is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operation system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock.

Rule Install the tmux Package [ref]

To enable console screen locking, install the tmux package. The tmux package can be installed with the following command:

$ sudo yum install tmux

A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to log out because of the temporary nature of the absence. The session lock is implemented at the point where session activity can be determined. Rather than be forced to wait for a period of time to expire before the user session can be locked, Red Hat Virtualization 4 needs to provide users with the ability to manually invoke a session lock so users can secure their session if it is necessary to temporarily vacate the immediate physical vicinity. Instruct users to begin new terminal sessions with the following command:

$ tmux

The console can now be locked with the following key combination:

ctrl+b :lock-session

Rationale:

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operation system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock.

The tmux package allows for a session lock to be implemented and configured.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_tmux_installed

References:

cis-csc	1, 12, 15, 16
cobit5	DSS05.04, DSS05.10, DSS06.10
cui	3.1.10
disa	CCI-000057, CCI-000056
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-6(a)
nist-csf	PR.AC-7
ospp	FMT_SMF_EXT.1, FMT_MOF_EXT.1, FTA_SSL.1
os-srg	SRG-OS-000030-GPOS-00011, SRG-OS-000028-GPOS-00009

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "tmux" ; then
    yum install -y "tmux"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[[packages]]
name = "tmux"
version = "*"

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.10
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_tmux_installed

- name: Ensure tmux is installed
  package:
    name: tmux
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.10
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_tmux_installed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable


package --add=tmux

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include install_tmux

class install_tmux {
  package { 'tmux':
    ensure => 'installed',
  }
}

Group Hardware Tokens for Authentication Group contains 5 rules

[ref] The use of hardware tokens such as smart cards for system login provides stronger, two-factor authentication than using a username and password. In Red Hat Enterprise Linux servers and workstations, hardware token login is not enabled by default and must be enabled in the system settings.

Rule Install the opensc Package For Multifactor Authentication [ref]

The opensc package can be installed with the following command:

$ sudo yum install opensc

Rationale:

Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.

Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD Common Access Card.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_opensc_installed

References:

disa	CCI-001953, CCI-004046
ism	1382, 1384, 1386
nist	CM-6(a)
os-srg	SRG-OS-000375-GPOS-00160, SRG-OS-000376-GPOS-00161

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "opensc" ; then
    yum install -y "opensc"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[[packages]]
name = "opensc"
version = "*"

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_opensc_installed

- name: Ensure opensc is installed
  package:
    name: opensc
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_opensc_installed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable


package --add=opensc

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include install_opensc

class install_opensc {
  package { 'opensc':
    ensure => 'installed',
  }
}

Rule Install the pcsc-lite package [ref]

The pcsc-lite package can be installed with the following command:

$ sudo yum install pcsc-lite

Rationale:

The pcsc-lite package must be installed if it is to be available for multifactor authentication using smartcards.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_pcsc-lite_installed

References:

disa	CCI-004046
ism	1382, 1384, 1386
nist	CM-6(a)
os-srg	SRG-OS-000375-GPOS-00160

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "pcsc-lite" ; then
    yum install -y "pcsc-lite"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[[packages]]
name = "pcsc-lite"
version = "*"

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_pcsc-lite_installed

- name: Ensure pcsc-lite is installed
  package:
    name: pcsc-lite
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_pcsc-lite_installed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable


package --add=pcsc-lite

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include install_pcsc-lite

class install_pcsc-lite {
  package { 'pcsc-lite':
    ensure => 'installed',
  }
}

Rule Enable the pcscd Service [ref]

The pcscd service can be enabled with the following command:

$ sudo systemctl enable pcscd.service

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_pcscd_enabled

References:

disa	CCI-004046
ism	1382, 1384, 1386
nist	IA-2(1), IA-2(2), IA-2(3), IA-2(4), IA-2(6), IA-2(7), IA-2(11), CM-6(a)
pcidss	Req-8.3
os-srg	SRG-OS-000375-GPOS-00160

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'pcscd.service'
"$SYSTEMCTL_EXEC" start 'pcscd.service'
"$SYSTEMCTL_EXEC" enable 'pcscd.service'

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
enabled = ["pcscd"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - NIST-800-53-IA-2(11)
  - NIST-800-53-IA-2(2)
  - NIST-800-53-IA-2(3)
  - NIST-800-53-IA-2(4)
  - NIST-800-53-IA-2(6)
  - NIST-800-53-IA-2(7)
  - PCI-DSS-Req-8.3
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_pcscd_enabled

- name: Enable service pcscd
  block:

  - name: Gather the package facts
    package_facts:
      manager: auto

  - name: Start service pcscd
    systemd:
      name: pcscd
      state: started
      masked: 'no'
    when:
    - '"pcsc-lite" in ansible_facts.packages'

  - name: Enable service pcscd
    ansible.builtin.command:
      cmd: systemctl enable pcscd
    when:
    - '"pcsc-lite" in ansible_facts.packages'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - NIST-800-53-IA-2(11)
  - NIST-800-53-IA-2(2)
  - NIST-800-53-IA-2(3)
  - NIST-800-53-IA-2(4)
  - NIST-800-53-IA-2(6)
  - NIST-800-53-IA-2(7)
  - PCI-DSS-Req-8.3
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_pcscd_enabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include enable_pcscd

class enable_pcscd {
  service {'pcscd':
    enable => true,
    ensure => 'running',
  }
}

Rule Configure opensc Smart Card Drivers [ref]

The OpenSC smart card tool can auto-detect smart card drivers; however, setting the smart card drivers in use by your organization helps to prevent users from using unauthorized smart cards. The default smart card driver for this profile is cac. To configure the OpenSC driver, edit the /etc/opensc.conf and add the following line into the file in the app default block, so it will look like:

app default {
   ...
   card_drivers = cac;
}

Rationale:

Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage PKI (public key infrastructure) in order to provide and verify credentials. Configuring the smart card driver in use by your organization helps to prevent users from using unauthorized smart cards.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_configure_opensc_card_drivers

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-001941, CCI-004045, CCI-000765, CCI-000766, CCI-000764
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	1382, 1384, 1386
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-2(1), IA-2(2), IA-2(3), IA-2(4), IA-2(6), IA-2(7), IA-2(11), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.3
os-srg	SRG-OS-000104-GPOS-00051, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000109-GPOS-00056, SRG-OS-000108-GPOS-00055, SRG-OS-000108-GPOS-00057, SRG-OS-000108-GPOS-00058

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

var_smartcard_drivers='cac'


OPENSC_TOOL="/usr/bin/opensc-tool"

if [ -f "${OPENSC_TOOL}" ]; then
    ${OPENSC_TOOL} -S app:default:card_drivers:$var_smartcard_drivers
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - NIST-800-53-IA-2(11)
  - NIST-800-53-IA-2(2)
  - NIST-800-53-IA-2(3)
  - NIST-800-53-IA-2(4)
  - NIST-800-53-IA-2(6)
  - NIST-800-53-IA-2(7)
  - PCI-DSS-Req-8.3
  - configure_opensc_card_drivers
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value var_smartcard_drivers # promote to variable
  set_fact:
    var_smartcard_drivers: !!str cac
  tags:
    - always

- name: Check existence of opensc conf
  stat:
    path: /etc/opensc-{{ ansible_architecture }}.conf
  register: opensc_conf_cd
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - NIST-800-53-IA-2(11)
  - NIST-800-53-IA-2(2)
  - NIST-800-53-IA-2(3)
  - NIST-800-53-IA-2(4)
  - NIST-800-53-IA-2(6)
  - NIST-800-53-IA-2(7)
  - PCI-DSS-Req-8.3
  - configure_opensc_card_drivers
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Configure smartcard driver block
  block:

  - name: Check if card_drivers is defined
    command: /usr/bin/opensc-tool -G app:default:card_drivers
    changed_when: false
    register: card_drivers

  - name: Configure opensc Smart Card Drivers
    command: |
      /usr/bin/opensc-tool -S app:default:card_drivers:{{ var_smartcard_drivers }}
    when:
    - card_drivers.stdout != var_smartcard_drivers
  when:
  - '"kernel" in ansible_facts.packages'
  - opensc_conf_cd.stat.exists
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - NIST-800-53-IA-2(11)
  - NIST-800-53-IA-2(2)
  - NIST-800-53-IA-2(3)
  - NIST-800-53-IA-2(4)
  - NIST-800-53-IA-2(6)
  - NIST-800-53-IA-2(7)
  - PCI-DSS-Req-8.3
  - configure_opensc_card_drivers
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Force opensc To Use Defined Smart Card Driver [ref]

The OpenSC smart card middleware can auto-detect smart card drivers; however by forcing the smart card driver in use by your organization, opensc will no longer autodetect or use other drivers unless specified. This helps to prevent users from using unauthorized smart cards. The default smart card driver for this profile is cac. To force the OpenSC driver, edit the /etc/opensc.conf. Look for a line similar to:

# force_card_driver = customcos;

and change it to:

force_card_driver = cac;

Rationale:

Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage PKI (public key infrastructure) in order to provide and verify credentials. Forcing the smart card driver in use by your organization helps to prevent users from using unauthorized smart cards.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_force_opensc_card_drivers

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-000765, CCI-000766, CCI-000767, CCI-000768, CCI-000771, CCI-000772, CCI-000884
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	1382, 1384, 1386
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-2(1), IA-2(2), IA-2(3), IA-2(4), IA-2(6), IA-2(7), IA-2(11), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.3
os-srg	SRG-OS-000104-GPOS-00051, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000109-GPOS-00056, SRG-OS-000108-GPOS-00055, SRG-OS-000108-GPOS-00057, SRG-OS-000108-GPOS-00058

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

var_smartcard_drivers='cac'


OPENSC_TOOL="/usr/bin/opensc-tool"

if [ -f "${OPENSC_TOOL}" ]; then
    ${OPENSC_TOOL} -S app:default:force_card_driver:$var_smartcard_drivers
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - NIST-800-53-IA-2(11)
  - NIST-800-53-IA-2(2)
  - NIST-800-53-IA-2(3)
  - NIST-800-53-IA-2(4)
  - NIST-800-53-IA-2(6)
  - NIST-800-53-IA-2(7)
  - PCI-DSS-Req-8.3
  - configure_strategy
  - force_opensc_card_drivers
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value var_smartcard_drivers # promote to variable
  set_fact:
    var_smartcard_drivers: !!str cac
  tags:
    - always

- name: Check existence of opensc conf
  stat:
    path: /etc/opensc-{{ ansible_architecture }}.conf
  register: opensc_conf_fcd
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - NIST-800-53-IA-2(11)
  - NIST-800-53-IA-2(2)
  - NIST-800-53-IA-2(3)
  - NIST-800-53-IA-2(4)
  - NIST-800-53-IA-2(6)
  - NIST-800-53-IA-2(7)
  - PCI-DSS-Req-8.3
  - configure_strategy
  - force_opensc_card_drivers
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Force smartcard driver block
  block:

  - name: Check if force_card_driver is defined
    command: /usr/bin/opensc-tool -G app:default:force_card_driver
    changed_when: false
    register: force_card_driver

  - name: Force opensc To Use Defined Smart Card Driver
    command: |
      /usr/bin/opensc-tool -S app:default:force_card_driver:{{ var_smartcard_drivers }}
    when:
    - force_card_driver.stdout != var_smartcard_drivers
  when:
  - '"kernel" in ansible_facts.packages'
  - opensc_conf_fcd.stat.exists
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - NIST-800-53-IA-2(11)
  - NIST-800-53-IA-2(2)
  - NIST-800-53-IA-2(3)
  - NIST-800-53-IA-2(4)
  - NIST-800-53-IA-2(6)
  - NIST-800-53-IA-2(7)
  - PCI-DSS-Req-8.3
  - configure_strategy
  - force_opensc_card_drivers
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Disable debug-shell SystemD Service [ref]

SystemD's debug-shell service is intended to diagnose SystemD related boot issues with various systemctl commands. Once enabled and following a system reboot, the root shell will be available on tty9 which is access by pressing CTRL-ALT-F9. The debug-shell service should only be used for SystemD related issues and should otherwise be disabled.

By default, the debug-shell SystemD service is already disabled. The debug-shell service can be disabled with the following command:

$ sudo systemctl mask --now debug-shell.service

Rationale:

This prevents attackers with physical access from trivially bypassing security on the machine through valid troubleshooting configurations and gaining root access when the system is rebooted.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_debug-shell_disabled

References:

cui	3.4.5
disa	CCI-000366, CCI-002235
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
nist	CM-6
ospp	FIA_UAU.1
os-srg	SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'debug-shell.service'
"$SYSTEMCTL_EXEC" disable 'debug-shell.service'
"$SYSTEMCTL_EXEC" mask 'debug-shell.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files debug-shell.socket; then
    "$SYSTEMCTL_EXEC" stop 'debug-shell.socket'
    "$SYSTEMCTL_EXEC" mask 'debug-shell.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'debug-shell.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
masked = ["debug-shell"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_debug-shell_disabled

- name: Disable debug-shell SystemD Service - Collect systemd Services Present in
    the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_debug-shell_disabled

- name: Disable debug-shell SystemD Service - Ensure debug-shell.service is Masked
  ansible.builtin.systemd:
    name: debug-shell.service
    state: stopped
    enabled: false
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - service_exists.stdout_lines is search("debug-shell.service", multiline=True)
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_debug-shell_disabled

- name: Unit Socket Exists - debug-shell.socket
  ansible.builtin.command: systemctl -q list-unit-files debug-shell.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_debug-shell_disabled

- name: Disable debug-shell SystemD Service - Disable Socket debug-shell
  ansible.builtin.systemd:
    name: debug-shell.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - socket_file_exists.stdout_lines is search("debug-shell.socket", multiline=True)
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_debug-shell_disabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include disable_debug-shell

class disable_debug-shell {
  service {'debug-shell':
    enable => false,
    ensure => 'stopped',
  }
}

Rule Disable Ctrl-Alt-Del Burst Action [ref]

By default, SystemD will reboot the system if the Ctrl-Alt-Del key sequence is pressed Ctrl-Alt-Delete more than 7 times in 2 seconds.

To configure the system to ignore the CtrlAltDelBurstAction setting, add or modify the following to /etc/systemd/system.conf:

CtrlAltDelBurstAction=none

Warning: Disabling the Ctrl-Alt-Del key sequence in /etc/init/control-alt-delete.conf DOES NOT disable the Ctrl-Alt-Del key sequence if running in runlevel 6 (e.g. in GNOME, KDE, etc.)! The Ctrl-Alt-Del key sequence will only be disabled if running in the non-graphical runlevel 3.

Rationale:

A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_disable_ctrlaltdel_burstaction

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.4.5
disa	CCI-000366, CCI-002235
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-6(a), AC-6(1), CM-6(a)
nist-csf	PR.AC-4, PR.DS-5
ospp	FAU_GEN.1.2
os-srg	SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && { rpm --quiet -q systemd; }; then

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^CtrlAltDelBurstAction=")

# shellcheck disable=SC2059
printf -v formatted_output "%s=%s" "$stripped_key" "none"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^CtrlAltDelBurstAction=\\>" "/etc/systemd/system.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^CtrlAltDelBurstAction=\\>.*/$escaped_formatted_output/gi" "/etc/systemd/system.conf"
else
    if [[ -s "/etc/systemd/system.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/systemd/system.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/systemd/system.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/systemd/system.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(a)
  - disable_ctrlaltdel_burstaction
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

- name: Disable Ctrl-Alt-Del Burst Action
  lineinfile:
    dest: /etc/systemd/system.conf
    state: present
    regexp: ^CtrlAltDelBurstAction
    line: CtrlAltDelBurstAction=none
    create: true
  when:
  - '"kernel" in ansible_facts.packages'
  - '"systemd" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(a)
  - disable_ctrlaltdel_burstaction
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

Rule Disable Ctrl-Alt-Del Reboot Activation [ref]

By default, SystemD will reboot the system if the Ctrl-Alt-Del key sequence is pressed.

To configure the system to ignore the Ctrl-Alt-Del key sequence from the command line instead of rebooting the system, do either of the following:

ln -sf /dev/null /etc/systemd/system/ctrl-alt-del.target

systemctl mask ctrl-alt-del.target

Do not simply delete the /usr/lib/systemd/system/ctrl-alt-del.service file, as this file may be restored during future system updates.

Rationale:

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_disable_ctrlaltdel_reboot

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.4.5
disa	CCI-000366, CCI-002235
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.DS-5
ospp	FAU_GEN.1.2
os-srg	SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then
    systemctl disable ctrl-alt-del.target
    systemctl mask ctrl-alt-del.target
else
    systemctl disable --now ctrl-alt-del.target
    systemctl mask --now ctrl-alt-del.target
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - disable_ctrlaltdel_reboot
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

- name: Disable Ctrl-Alt-Del Reboot Activation
  systemd:
    name: ctrl-alt-del.target
    force: true
    masked: true
    state: stopped
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - disable_ctrlaltdel_reboot
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed

Rule Verify that Interactive Boot is Disabled [ref]

Red Hat Virtualization 4 systems support an "interactive boot" option that can be used to prevent services from being started. On a Red Hat Virtualization 4 system, interactive boot can be enabled by providing a 1, yes, true, or on value to the systemd.confirm_spawn kernel argument in /etc/default/grub. Remove any instance of

systemd.confirm_spawn=(1|yes|true|on)

from the kernel arguments in that file to disable interactive boot. Recovery booting must also be disabled. Confirm that GRUB_DISABLE_RECOVERY=true is set in /etc/default/grub. It is also required to change the runtime configuration, run:

/sbin/grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"

grub2-mkconfig -o /boot/grub2/grub.cfg

Rationale:

Using interactive or recovery boot, the console user could disable auditing, firewalls, or other services, weakening system security.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_grub2_disable_interactive_boot

References:

cis-csc	11, 12, 14, 15, 16, 18, 3, 5
cobit5	DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06
cui	3.1.2, 3.4.5
disa	CCI-000366
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7
iso27001-2013	A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	SC-2(1), CM-6(a)
nist-csf	PR.AC-4, PR.AC-6, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && { rpm --quiet -q grub2-common; }; then

# Verify that Interactive Boot is Disabled in /etc/default/grub
CONFIRM_SPAWN_YES="systemd.confirm_spawn\(=\(1\|yes\|true\|on\)\|\b\)"
CONFIRM_SPAWN_NO="systemd.confirm_spawn=no"

if grep -q "\(GRUB_CMDLINE_LINUX\|GRUB_CMDLINE_LINUX_DEFAULT\)" /etc/default/grub
then
	sed -i "s/${CONFIRM_SPAWN_YES}/${CONFIRM_SPAWN_NO}/" /etc/default/grub
fi

# make sure GRUB_DISABLE_RECOVERY=true
if grep -q '^GRUB_DISABLE_RECOVERY=.*'  '/etc/default/grub' ; then
       # modify the GRUB command-line if an GRUB_DISABLE_RECOVERY= arg already exists
       sed -i 's/GRUB_DISABLE_RECOVERY=.*/GRUB_DISABLE_RECOVERY=true/' /etc/default/grub
else
       # no GRUB_DISABLE_RECOVERY=arg is present, append it to file
       echo "GRUB_DISABLE_RECOVERY=true"  >> '/etc/default/grub'
fi



# Remove 'systemd.confirm_spawn' kernel argument also from runtime settings
/sbin/grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"


#Regen grub.cfg handle updated GRUB_DISABLE_RECOVERY and confirm_spawn
grub2-mkconfig -o /boot/grub2/grub.cfg

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-2(1)
  - grub2_disable_interactive_boot
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Verify GRUB_DISABLE_RECOVERY=true
  lineinfile:
    path: /etc/default/grub
    regexp: ^GRUB_DISABLE_RECOVERY=.*
    line: GRUB_DISABLE_RECOVERY=true
    state: present
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-2(1)
  - grub2_disable_interactive_boot
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Verify that Interactive Boot is Disabled in /etc/default/grub
  replace:
    dest: /etc/default/grub
    regexp: systemd.confirm_spawn(=(1|yes|true|on)|\b)
    replace: systemd.confirm_spawn=no
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-2(1)
  - grub2_disable_interactive_boot
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Verify that Interactive Boot is Disabled (runtime)
  command: /sbin/grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-2(1)
  - grub2_disable_interactive_boot
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Regen grub.cfg handle updated GRUB_DISABLE_RECOVERY and confirm_spawn
  command: grub2-mkconfig -o  /boot/grub2/grub.cfg
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.4.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-2(1)
  - grub2_disable_interactive_boot
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Require Authentication for Single User Mode [ref]

Single-user mode is intended as a system recovery method, providing a single user root access to the system by providing a boot option at startup.

By default, single-user mode is protected by requiring a password and is set in /usr/lib/systemd/system/rescue.service.

Rationale:

This prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_require_singleuser_auth

References:

cis-csc	1, 11, 12, 14, 15, 16, 18, 3, 5
cobit5	DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10
cui	3.1.1, 3.4.5
disa	CCI-000213
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	IA-2, AC-3, CM-6(a)
nist-csf	PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3
ospp	FIA_UAU.1
os-srg	SRG-OS-000080-GPOS-00048

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

found=false

# set value in all files if they contain section or key
for f in $(echo -n "/etc/systemd/system/rescue.service.d/10-oscap.conf"); do
    if [ ! -e "$f" ]; then
        continue
    fi

    # find key in section and change value
    if grep -qzosP "[[:space:]]*\[Service\]([^\n\[]*\n+)+?[[:space:]]*ExecStart" "$f"; then

            sed -i "s/ExecStart[^(\n)]*/ExecStart=-/bin/sh -c "/sbin/sulogin; /usr/bin/systemctl --fail --no-block default"/" "$f"

            found=true

    # find section and add key = value to it
    elif grep -qs "[[:space:]]*\[Service\]" "$f"; then

            sed -i "/[[:space:]]*\[Service\]/a ExecStart=-/bin/sh -c "/sbin/sulogin; /usr/bin/systemctl --fail --no-block default"" "$f"

            found=true
    fi
done

# if section not in any file, append section with key = value to FIRST file in files parameter
if ! $found ; then
    file=$(echo "/etc/systemd/system/rescue.service.d/10-oscap.conf" | cut -f1 -d ' ')
    mkdir -p "$(dirname "$file")"

    echo -e "[Service]\nExecStart=-/bin/sh -c "/sbin/sulogin; /usr/bin/systemctl --fail --no-block default"" >> "$file"

fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.1
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - require_singleuser_auth
  - restrict_strategy

- name: Require single user mode password
  lineinfile:
    create: true
    dest: /usr/lib/systemd/system/rescue.service
    regexp: ^#?ExecStart=
    line: ExecStart=-/bin/sh -c "/sbin/sulogin; /usr/bin/systemctl --fail --no-block
      default"
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.1
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - require_singleuser_auth
  - restrict_strategy

Group Protect Accounts by Restricting Password-Based Login Group contains 4 groups and 15 rules

[ref] Conventionally, Unix shell accounts are accessed by providing a username and password to a login program, which tests these values for correctness using the /etc/passwd and /etc/shadow files. Password-based login is vulnerable to guessing of weak passwords, and to sniffing and man-in-the-middle attacks against passwords entered over a network or at an insecure console. Therefore, mechanisms for accessing accounts by entering usernames and passwords should be restricted to those which are operationally necessary.

Group Set Account Expiration Parameters Group contains 2 rules

[ref] Accounts can be configured to be automatically disabled after a certain time period, meaning that they will require administrator interaction to become usable again. Expiration of accounts after inactivity can be set for all accounts by default and also on a per-account basis, such as for accounts that are known to be temporary. To configure automatic expiration of an account following the expiration of its password (that is, after the password has expired and not been changed), run the following command, substituting NUM_DAYS and USER appropriately:

$ sudo chage -I NUM_DAYS USER

Accounts, such as temporary accounts, can also be configured to expire on an explicitly-set date with the -E option. The file /etc/default/useradd controls default settings for all newly-created accounts created with the system's normal command line utilities.

Warning: This will only apply to newly created accounts

Rule Set Account Expiration Following Inactivity [ref]

To specify the number of days after a password expires (which signifies inactivity) until an account is permanently disabled, add or correct the following line in /etc/default/useradd:

INACTIVE=35

If a password is currently on the verge of expiration, then 35 day(s) remain(s) until the account is automatically disabled. However, if the password will not expire for another 60 days, then 60 days plus 35 day(s) could elapse until the account would be automatically disabled. See the useradd man page for more information.

Rationale:

Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system. Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_account_disable_post_pw_expiration

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8
cjis	5.6.2.1.1
cobit5	DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.5.6
disa	CCI-003628, CCI-003627
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	IA-4(e), AC-2(3), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7
pcidss	Req-8.1.4
os-srg	SRG-OS-000118-GPOS-00060
pcidss4	8.2.6, 8.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then

var_account_disable_post_pw_expiration='35'


# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^INACTIVE")

# shellcheck disable=SC2059
printf -v formatted_output "%s=%s" "$stripped_key" "$var_account_disable_post_pw_expiration"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^INACTIVE\\>" "/etc/default/useradd"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^INACTIVE\\>.*/$escaped_formatted_output/gi" "/etc/default/useradd"
else
    if [[ -s "/etc/default/useradd" ]] && [[ -n "$(tail -c 1 -- "/etc/default/useradd" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/default/useradd"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/default/useradd"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.6
  - NIST-800-53-AC-2(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-4(e)
  - PCI-DSS-Req-8.1.4
  - PCI-DSSv4-8.2
  - PCI-DSSv4-8.2.6
  - account_disable_post_pw_expiration
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_account_disable_post_pw_expiration # promote to variable
  set_fact:
    var_account_disable_post_pw_expiration: !!str 35
  tags:
    - always

- name: Set Account Expiration Following Inactivity
  lineinfile:
    create: true
    dest: /etc/default/useradd
    regexp: ^INACTIVE
    line: INACTIVE={{ var_account_disable_post_pw_expiration }}
  when: '"shadow-utils" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.6
  - NIST-800-53-AC-2(3)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-4(e)
  - PCI-DSS-Req-8.1.4
  - PCI-DSSv4-8.2
  - PCI-DSSv4-8.2.6
  - account_disable_post_pw_expiration
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Assign Expiration Date to Temporary Accounts [ref]

Temporary accounts are established as part of normal account activation procedures when there is a need for short-term accounts. In the event temporary accounts are required, configure the system to terminate them after a documented time period. For every temporary account, run the following command to set an expiration date on it, substituting USER and YYYY-MM-DD appropriately:

$ sudo chage -E YYYY-MM-DD USER

YYYY-MM-DD indicates the documented expiration date for the account. For U.S. Government systems, the operating system must be configured to automatically terminate these types of accounts after a period of 72 hours.

Rationale:

If temporary user accounts remain active when no longer needed or for an excessive period, these accounts may be used to gain unauthorized access. To mitigate this risk, automated termination of all temporary accounts must be set upon account creation.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_account_temp_expire_date

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8
cobit5	DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS06.03
disa	CCI-000016, CCI-001682
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.3, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nist	AC-2(2), AC-2(3), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6
os-srg	SRG-OS-000123-GPOS-00064, SRG-OS-000002-GPOS-00002

Group Set Password Expiration Parameters Group contains 6 rules

[ref] The file /etc/login.defs controls several password-related settings. Programs such as passwd, su, and login consult /etc/login.defs to determine behavior with regard to password aging, expiration warnings, and length. See the man page login.defs(5) for more information.

Users should be forced to change their passwords, in order to decrease the utility of compromised passwords. However, the need to change passwords often should be balanced against the risk that users will reuse or write down passwords if forced to change them too often. Forcing password changes every 90-360 days, depending on the environment, is recommended. Set the appropriate value as PASS_MAX_DAYS and apply it to existing accounts with the -M flag.

The PASS_MIN_DAYS (-m) setting prevents password changes for 7 days after the first change, to discourage password cycling. If you use this setting, train users to contact an administrator for an emergency password change in case a new password becomes compromised. The PASS_WARN_AGE (-W) setting gives users 7 days of warnings at login time that their passwords are about to expire.

For example, for each existing human user USER, expiration parameters could be adjusted to a 180 day maximum password age, 7 day minimum password age, and 7 day warning period with the following command:

$ sudo chage -M 180 -m 7 -W 7 USER

Rule Set Password Maximum Age [ref]

To specify password maximum age for new accounts, edit the file /etc/login.defs and add or correct the following line:

PASS_MAX_DAYS 60

A value of 180 days is sufficient for many environments. The DoD requirement is 60. The profile requirement is 60.

Rationale:

Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If the operating system does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the operating system passwords could be compromised.

Setting the password maximum age ensures users are required to periodically change their passwords. Requiring shorter password lifetimes increases the risk of users writing down the password in a convenient location subject to physical compromise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_maximum_age_login_defs

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.1
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.5.6
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0418, 1055, 1402
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(f), IA-5(1)(d), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.2.4
os-srg	SRG-OS-000076-GPOS-00044
pcidss4	8.3.9, 8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then

var_accounts_maximum_age_login_defs='60'

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^PASS_MAX_DAYS")

# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_maximum_age_login_defs"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^PASS_MAX_DAYS\\>" "/etc/login.defs"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^PASS_MAX_DAYS\\>.*/$escaped_formatted_output/gi" "/etc/login.defs"
else
    if [[ -s "/etc/login.defs" ]] && [[ -n "$(tail -c 1 -- "/etc/login.defs" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/login.defs"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/login.defs"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.1
  - NIST-800-171-3.5.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(d)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.4
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.9
  - accounts_maximum_age_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_maximum_age_login_defs # promote to variable
  set_fact:
    var_accounts_maximum_age_login_defs: !!str 60
  tags:
    - always

- name: Set Password Maximum Age
  lineinfile:
    create: true
    dest: /etc/login.defs
    regexp: ^#?PASS_MAX_DAYS
    line: PASS_MAX_DAYS {{ var_accounts_maximum_age_login_defs }}
  when: '"shadow-utils" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.1
  - NIST-800-171-3.5.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(d)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.4
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.9
  - accounts_maximum_age_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Set Password Minimum Age [ref]

To specify password minimum age for new accounts, edit the file /etc/login.defs and add or correct the following line:

PASS_MIN_DAYS 7

A value of 1 day is considered sufficient for many environments. The DoD requirement is 1. The profile requirement is 7.

Rationale:

Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, then the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.

Setting the minimum password age protects against users cycling back to a favorite password after satisfying the password reuse requirement.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_minimum_age_login_defs

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.1.1
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.5.8
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0418, 1055, 1402
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(f), IA-5(1)(d), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000075-GPOS-00043

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then

var_accounts_minimum_age_login_defs='7'

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^PASS_MIN_DAYS")

# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_minimum_age_login_defs"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^PASS_MIN_DAYS\\>" "/etc/login.defs"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^PASS_MIN_DAYS\\>.*/$escaped_formatted_output/gi" "/etc/login.defs"
else
    if [[ -s "/etc/login.defs" ]] && [[ -n "$(tail -c 1 -- "/etc/login.defs" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/login.defs"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/login.defs"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(d)
  - NIST-800-53-IA-5(f)
  - accounts_minimum_age_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_minimum_age_login_defs # promote to variable
  set_fact:
    var_accounts_minimum_age_login_defs: !!str 7
  tags:
    - always

- name: Set Password Minimum Age
  lineinfile:
    create: true
    dest: /etc/login.defs
    regexp: ^#?PASS_MIN_DAYS
    line: PASS_MIN_DAYS {{ var_accounts_minimum_age_login_defs }}
  when: '"shadow-utils" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.1.1
  - NIST-800-171-3.5.8
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(d)
  - NIST-800-53-IA-5(f)
  - accounts_minimum_age_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Set Password Minimum Length in login.defs [ref]

To specify password length requirements for new accounts, edit the file /etc/login.defs and add or correct the following line:

PASS_MIN_LEN 6

The DoD requirement is 15. The FISMA requirement is 12. The profile requirement is 6. If a program consults /etc/login.defs and also another PAM module (such as pam_pwquality) during a password change operation, then the most restrictive must be satisfied. See PAM section for more information about enforcing password quality requirements.

Rationale:

Requiring a minimum password length makes password cracking attacks more difficult by ensuring a larger search space. However, any security benefit from an onerous requirement must be carefully weighed against usability problems, support costs, or counterproductive behavior that may result.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_minlen_login_defs

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.6.2.1
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.5.7
disa	CCI-004066
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(f), IA-5(1)(a), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000078-GPOS-00046
anssi	R31

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then

var_accounts_password_minlen_login_defs='6'

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^PASS_MIN_LEN")

# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_password_minlen_login_defs"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^PASS_MIN_LEN\\>" "/etc/login.defs"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^PASS_MIN_LEN\\>.*/$escaped_formatted_output/gi" "/etc/login.defs"
else
    if [[ -s "/etc/login.defs" ]] && [[ -n "$(tail -c 1 -- "/etc/login.defs" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/login.defs"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/login.defs"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.6.2.1
  - NIST-800-171-3.5.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(f)
  - accounts_password_minlen_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_password_minlen_login_defs # promote to variable
  set_fact:
    var_accounts_password_minlen_login_defs: !!str 6
  tags:
    - always

- name: Set Password Minimum Length in login.defs
  lineinfile:
    dest: /etc/login.defs
    regexp: ^PASS_MIN_LEN *[0-9]*
    state: present
    line: PASS_MIN_LEN        {{ var_accounts_password_minlen_login_defs }}
    create: true
  when: '"shadow-utils" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.1
  - NIST-800-171-3.5.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(f)
  - accounts_password_minlen_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Set Existing Passwords Maximum Age [ref]

Configure non-compliant accounts to enforce a 60-day maximum password lifetime restriction by running the following command:

$ sudo chage -M 60
          USER

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_set_max_life_existing

References:

disa	CCI-004066
nist	IA-5(f), IA-5(1)(d), CM-6(a)
os-srg	SRG-OS-000076-GPOS-00044
pcidss4	8.3.9, 8.3

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


var_accounts_maximum_age_login_defs='60'


while IFS= read -r i; do
    
    chage -M $var_accounts_maximum_age_login_defs $i

done <   <(awk -v var="$var_accounts_maximum_age_login_defs" -F: '(/^[^:]+:[^!*]/ && ($5 > var || $5 == "")) {print $1}' /etc/shadow)

Rule Set Existing Passwords Minimum Age [ref]

Configure non-compliant accounts to enforce a 24 hours/1 day minimum password lifetime by running the following command:

$ sudo chage -m 1 USER

Rationale:

Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_set_min_life_existing

References:

disa	CCI-004066
nist	IA-5(f), IA-5(1)(d), CM-6(a)
os-srg	SRG-OS-000075-GPOS-00043

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


var_accounts_minimum_age_login_defs='7'


while IFS= read -r i; do
    
    chage -m $var_accounts_minimum_age_login_defs $i

done <   <(awk -v var="$var_accounts_minimum_age_login_defs" -F: '(/^[^:]+:[^!*]/ && ($4 < var || $4 == "")) {print $1}' /etc/shadow)

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: XCCDF Value var_accounts_minimum_age_login_defs # promote to variable
  set_fact:
    var_accounts_minimum_age_login_defs: !!str 7
  tags:
    - always

- name: Collect users with not correct minimum time period between password changes
  command: |
    awk -F':' '(/^[^:]+:[^!*]/ && ($4 < {{ var_accounts_minimum_age_login_defs }} || $4 == "")) {print $1}' /etc/shadow
  register: user_names
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(d)
  - NIST-800-53-IA-5(f)
  - accounts_password_set_min_life_existing
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Change the minimum time period between password changes
  command: |
    chage -m {{ var_accounts_minimum_age_login_defs }} {{ item }}
  with_items: '{{ user_names.stdout_lines }}'
  when: user_names.stdout_lines | length > 0
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(d)
  - NIST-800-53-IA-5(f)
  - accounts_password_set_min_life_existing
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Set Password Warning Age [ref]

To specify how many days prior to password expiration that a warning will be issued to users, edit the file /etc/login.defs and add or correct the following line:

PASS_WARN_AGE 7

The DoD requirement is 7. The profile requirement is 7.

Rationale:

Setting the password warning age enables users to make the change at a practical time.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_warn_age_login_defs

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8
cobit5	DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.5.8
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2
ism	0418, 1055, 1402
iso27001-2013	A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nist	IA-5(f), IA-5(1)(d), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7
pcidss	Req-8.2.4
pcidss4	8.3.9, 8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then

var_accounts_password_warn_age_login_defs='7'

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^PASS_WARN_AGE")

# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_password_warn_age_login_defs"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^PASS_WARN_AGE\\>" "/etc/login.defs"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^PASS_WARN_AGE\\>.*/$escaped_formatted_output/gi" "/etc/login.defs"
else
    if [[ -s "/etc/login.defs" ]] && [[ -n "$(tail -c 1 -- "/etc/login.defs" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/login.defs"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/login.defs"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.5.8
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(d)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.4
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.9
  - accounts_password_warn_age_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_password_warn_age_login_defs # promote to variable
  set_fact:
    var_accounts_password_warn_age_login_defs: !!str 7
  tags:
    - always

- name: Set Password Warning Age
  lineinfile:
    dest: /etc/login.defs
    regexp: ^PASS_WARN_AGE *[0-9]*
    state: present
    line: PASS_WARN_AGE        {{ var_accounts_password_warn_age_login_defs }}
    create: true
  when: '"shadow-utils" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.5.8
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(d)
  - NIST-800-53-IA-5(f)
  - PCI-DSS-Req-8.2.4
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.9
  - accounts_password_warn_age_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Group Verify Proper Storage and Existence of Password Hashes Group contains 3 rules

[ref] By default, password hashes for local accounts are stored in the second field (colon-separated) in /etc/shadow. This file should be readable only by processes running with root credentials, preventing users from casually accessing others' password hashes and attempting to crack them. However, it remains possible to misconfigure the system and store password hashes in world-readable files such as /etc/passwd, or to even store passwords themselves in plaintext on the system. Using system-provided tools for password change/creation should allow administrators to avoid such misconfiguration.

Rule Verify All Account Password Hashes are Shadowed [ref]

If any password hashes are stored in /etc/passwd (in the second field, instead of an x or *), the cause of this misconfiguration should be investigated. The account should have its password reset and the hash should be properly stored, or the account should be deleted entirely.

Rationale:

The hashes for all user account passwords should be stored in the file /etc/shadow and never in /etc/passwd, which is readable by all users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_password_all_shadowed

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.5.2
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.5.10
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
ism	1410
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-5(h), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.2.1
pcidss4	8.3.2, 8.3

Rule All GIDs referenced in /etc/passwd must be defined in /etc/group [ref]

Add a group to the system for each GID referenced without a corresponding group.

Rationale:

If a user is assigned the Group Identifier (GID) of a group not existing on the system, and a group with the Group Identifier (GID) is subsequently created, the user may have unintended rights to any files associated with the group.

Severity:

low

Rule ID:

xccdf_org.ssgproject.content_rule_gid_passwd_group_same

References:

cis-csc	1, 12, 15, 16, 5
cjis	5.5.2
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-000764
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	IA-2, CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
pcidss	Req-8.5.a
os-srg	SRG-OS-000104-GPOS-00051
pcidss4	8.2.2, 8.2

Rule Prevent Login to Accounts With Empty Password [ref]

If an account is configured for password authentication but does not have an assigned password, it may be possible to log into the account without authentication. Remove any instances of the nullok in /etc/pam.d/system-auth and /etc/pam.d/password-auth to prevent logins with empty passwords.

Warning: If the system relies on authselect tool to manage PAM settings, the remediation will also use authselect tool. However, if any manual modification was made in PAM files, the authselect integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report. Note that this rule is not applicable for systems running within a container. Having user with empty password within a container is not considered a risk, because it should not be possible to directly login into a container anyway.

Rationale:

If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_no_empty_passwords

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 3, 5
cjis	5.5.2
cobit5	APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10
cui	3.1.1, 3.1.5
disa	CCI-000366
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nist	IA-5(1)(a), IA-5(c), CM-6(a)
nist-csf	PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5
ospp	FIA_UAU.1
pcidss	Req-8.2.3
os-srg	SRG-OS-000480-GPOS-00227
pcidss4	8.3.1, 8.3

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -f /usr/bin/authselect ]; then
    if ! authselect check; then
echo "
authselect integrity check failed. Remediation aborted!
This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
It is not recommended to manually edit the PAM files when authselect tool is available.
In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
exit 1
fi
authselect enable-feature without-nullok

authselect apply-changes -b
else
    
if grep -qP "^\s*auth\s+sufficient\s+pam_unix.so\s.*\bnullok\b" "/etc/pam.d/system-auth"; then
    sed -i -E --follow-symlinks "s/(.*auth.*sufficient.*pam_unix.so.*)\snullok=?[[:alnum:]]*(.*)/\1\2/g" "/etc/pam.d/system-auth"
fi
    
if grep -qP "^\s*password\s+sufficient\s+pam_unix.so\s.*\bnullok\b" "/etc/pam.d/system-auth"; then
    sed -i -E --follow-symlinks "s/(.*password.*sufficient.*pam_unix.so.*)\snullok=?[[:alnum:]]*(.*)/\1\2/g" "/etc/pam.d/system-auth"
fi
    
if grep -qP "^\s*auth\s+sufficient\s+pam_unix.so\s.*\bnullok\b" "/etc/pam.d/password-auth"; then
    sed -i -E --follow-symlinks "s/(.*auth.*sufficient.*pam_unix.so.*)\snullok=?[[:alnum:]]*(.*)/\1\2/g" "/etc/pam.d/password-auth"
fi
    
if grep -qP "^\s*password\s+sufficient\s+pam_unix.so\s.*\bnullok\b" "/etc/pam.d/password-auth"; then
    sed -i -E --follow-symlinks "s/(.*password.*sufficient.*pam_unix.so.*)\snullok=?[[:alnum:]]*(.*)/\1\2/g" "/etc/pam.d/password-auth"
fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Kubernetes snippet ⇲

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      files:
      - contents:
          source: data:,%23%20Generated%20by%20authselect%20on%20Sat%20Oct%2027%2014%3A59%3A36%202018%0A%23%20Do%20not%20modify%20this%20file%20manually.%0A%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_env.so%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_faildelay.so%20delay%3D2000000%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_fprintd.so%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20try_first_pass%0Aauth%20%20%20%20%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet_success%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20forward_pass%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3C%201000%20quiet%0Aaccount%20%20%20%20%20%5Bdefault%3Dbad%20success%3Dok%20user_unknown%3Dignore%5D%20pam_sss.so%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_permit.so%0A%0Apassword%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_pwquality.so%20try_first_pass%20local_users_only%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20sha512%20shadow%20try_first_pass%20use_authtok%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20use_authtok%0Apassword%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_keyinit.so%20revoke%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_limits.so%0A-session%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_systemd.so%0Asession%20%20%20%20%20%5Bsuccess%3D1%20default%3Dignore%5D%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20service%20in%20crond%20quiet%20use_uid%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%0A
        mode: 0644
        path: /etc/pam.d/password-auth
        overwrite: true
      - contents:
          source: data:,%23%20Generated%20by%20authselect%20on%20Sat%20Oct%2027%2014%3A59%3A36%202018%0A%23%20Do%20not%20modify%20this%20file%20manually.%0A%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_env.so%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_faildelay.so%20delay%3D2000000%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_fprintd.so%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20try_first_pass%0Aauth%20%20%20%20%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet_success%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20forward_pass%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3C%201000%20quiet%0Aaccount%20%20%20%20%20%5Bdefault%3Dbad%20success%3Dok%20user_unknown%3Dignore%5D%20pam_sss.so%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_permit.so%0A%0Apassword%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_pwquality.so%20try_first_pass%20local_users_only%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20sha512%20shadow%20try_first_pass%20use_authtok%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20use_authtok%0Apassword%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_keyinit.so%20revoke%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_limits.so%0A-session%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_systemd.so%0Asession%20%20%20%20%20%5Bsuccess%3D1%20default%3Dignore%5D%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20service%20in%20crond%20quiet%20use_uid%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%0A
        mode: 0644
        path: /etc/pam.d/system-auth
        overwrite: true

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.2
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.1
  - configure_strategy
  - high_severity
  - low_complexity
  - medium_disruption
  - no_empty_passwords
  - no_reboot_needed

- name: Prevent Login to Accounts With Empty Password - Check if system relies on
    authselect
  ansible.builtin.stat:
    path: /usr/bin/authselect
  register: result_authselect_present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.2
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.1
  - configure_strategy
  - high_severity
  - low_complexity
  - medium_disruption
  - no_empty_passwords
  - no_reboot_needed

- name: Prevent Login to Accounts With Empty Password - Remediate using authselect
  block:

  - name: Prevent Login to Accounts With Empty Password - Check integrity of authselect
      current profile
    ansible.builtin.command:
      cmd: authselect check
    register: result_authselect_check_cmd
    changed_when: false
    failed_when: false

  - name: Prevent Login to Accounts With Empty Password - Informative message based
      on the authselect integrity check result
    ansible.builtin.assert:
      that:
      - result_authselect_check_cmd.rc == 0
      fail_msg:
      - authselect integrity check failed. Remediation aborted!
      - This remediation could not be applied because an authselect profile was not
        selected or the selected profile is not intact.
      - It is not recommended to manually edit the PAM files when authselect tool
        is available.
      - In cases where the default authselect profile does not cover a specific demand,
        a custom authselect profile is recommended.
      success_msg:
      - authselect integrity check passed

  - name: Prevent Login to Accounts With Empty Password - Get authselect current features
    ansible.builtin.shell:
      cmd: authselect current | tail -n+3 | awk '{ print $2 }'
    register: result_authselect_features
    changed_when: false
    when:
    - result_authselect_check_cmd is success

  - name: Prevent Login to Accounts With Empty Password - Ensure "without-nullok"
      feature is enabled using authselect tool
    ansible.builtin.command:
      cmd: authselect enable-feature without-nullok
    register: result_authselect_enable_feature_cmd
    when:
    - result_authselect_check_cmd is success
    - result_authselect_features.stdout is not search("without-nullok")

  - name: Prevent Login to Accounts With Empty Password - Ensure authselect changes
      are applied
    ansible.builtin.command:
      cmd: authselect apply-changes -b
    when:
    - result_authselect_enable_feature_cmd is not skipped
    - result_authselect_enable_feature_cmd is success
  when:
  - '"kernel" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.2
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.1
  - configure_strategy
  - high_severity
  - low_complexity
  - medium_disruption
  - no_empty_passwords
  - no_reboot_needed

- name: Prevent Login to Accounts With Empty Password - Remediate directly editing
    PAM files
  ansible.builtin.replace:
    dest: '{{ item }}'
    regexp: nullok
  loop:
  - /etc/pam.d/system-auth
  - /etc/pam.d/password-auth
  when:
  - '"kernel" in ansible_facts.packages'
  - not result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.2
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)(a)
  - NIST-800-53-IA-5(c)
  - PCI-DSS-Req-8.2.3
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.1
  - configure_strategy
  - high_severity
  - low_complexity
  - medium_disruption
  - no_empty_passwords
  - no_reboot_needed

Group Restrict Root Logins Group contains 4 rules

[ref] Direct root logins should be allowed only for emergency use. In normal situations, the administrator should access the system via a unique unprivileged account, and then use su or sudo to execute privileged commands. Discouraging administrators from accessing the root account directly ensures an audit trail in organizations with multiple administrators. Locking down the channels through which root can connect directly also reduces opportunities for password-guessing against the root account. The login program uses the file /etc/securetty to determine which interfaces should allow root logins. The virtual devices /dev/console and /dev/tty* represent the system consoles (accessible via the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default installation). The default securetty file also contains /dev/vc/*. These are likely to be deprecated in most environments, but may be retained for compatibility. Root should also be prohibited from connecting via network protocols. Other sections of this document include guidance describing how to prevent root from logging in via SSH.

Rule Verify Only Root Has UID 0 [ref]

If any account other than root has a UID of 0, this misconfiguration should be investigated and the accounts other than root should be removed or have their UID changed.
If the account is associated with system commands or applications the UID should be changed to one greater than "0" but less than "1000." Otherwise assign a UID greater than "1000" that has not already been assigned.

Rationale:

An account has root authority if it has a UID of 0. Multiple accounts with a UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account. Proper configuration of sudo is recommended to afford multiple system administrators access to root privileges in an accountable manner.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_accounts_no_uid_except_zero

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10
cui	3.1.1, 3.1.5
disa	CCI-000366
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	IA-2, AC-6(5), IA-4(b)
nist-csf	PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5
pcidss	Req-8.5
os-srg	SRG-OS-000480-GPOS-00227
pcidss4	8.2.1, 8.2

Remediation Shell script ⇲

awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs --no-run-if-empty --max-lines=1 passwd -l

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Get all /etc/passwd file entries
  getent:
    database: passwd
    split: ':'
  tags:
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-AC-6(5)
  - NIST-800-53-IA-2
  - NIST-800-53-IA-4(b)
  - PCI-DSS-Req-8.5
  - PCI-DSSv4-8.2
  - PCI-DSSv4-8.2.1
  - accounts_no_uid_except_zero
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

- name: Lock the password of the user accounts other than root with uid 0
  command: passwd -l {{ item.key }}
  loop: '{{ getent_passwd | dict2items | rejectattr(''key'', ''search'', ''root'')
    | list }}'
  when: item.value.1  == '0'
  tags:
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-AC-6(5)
  - NIST-800-53-IA-2
  - NIST-800-53-IA-4(b)
  - PCI-DSS-Req-8.5
  - PCI-DSSv4-8.2
  - PCI-DSSv4-8.2.1
  - accounts_no_uid_except_zero
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy

Rule Direct root Logins Not Allowed [ref]

To further limit access to the root account, administrators can disable root logins at the console by editing the /etc/securetty file. This file lists all devices the root user is allowed to login to. If the file does not exist at all, the root user can login through any communication device on the system, whether via the console or via a raw network interface. This is dangerous as user can login to the system as root via Telnet, which sends the password in plain text over the network. By default, Red Hat Virtualization 4's /etc/securetty file only allows the root user to login at the console physically attached to the system. To prevent root from logging in, remove the contents of this file. To prevent direct root logins, remove the contents of this file by typing the following command:

$ sudo echo > /etc/securetty

Warning: This rule only checks the /etc/securetty file existence and its content. If you need to restrict user access using the /etc/securetty file, make sure the pam_securetty.so PAM module is properly enabled in relevant PAM files.

Rationale:

Disabling direct root logins ensures proper accountability and multifactor authentication to privileged accounts. Users will first login, then escalate to privileged (root) access via su / sudo. This is required for FISMA Low and FISMA Moderate systems.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_no_direct_root_logins

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.1.1, 3.1.6
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	IA-2, CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
anssi	R33
pcidss4	8.6.1, 8.6

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

echo > /etc/securetty

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2
  - PCI-DSSv4-8.6
  - PCI-DSSv4-8.6.1
  - low_complexity
  - low_disruption
  - medium_severity
  - no_direct_root_logins
  - no_reboot_needed
  - restrict_strategy

- name: Direct root Logins Not Allowed
  copy:
    dest: /etc/securetty
    content: ''
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2
  - PCI-DSSv4-8.6
  - PCI-DSSv4-8.6.1
  - low_complexity
  - low_disruption
  - medium_severity
  - no_direct_root_logins
  - no_reboot_needed
  - restrict_strategy

Rule Restrict Serial Port Root Logins [ref]

To restrict root logins on serial ports, ensure lines of this form do not appear in /etc/securetty:

ttyS0
ttyS1

Rationale:

Preventing direct root login to serial port interfaces helps ensure accountability for actions taken on the systems using the root account.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_restrict_serial_port_logins

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.1.1, 3.1.5
disa	CCI-000770
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	AC-6, CM-6(a)
nist-csf	PR.AC-4, PR.DS-5

Remediation Shell script ⇲

sed -i '/ttyS/d' /etc/securetty

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Restrict Serial Port Root Logins
  lineinfile:
    dest: /etc/securetty
    regexp: ttyS[0-9]
    state: absent
  tags:
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(a)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_serial_port_logins
  - restrict_strategy

Rule Restrict Virtual Console Root Logins [ref]

To restrict root logins through the (deprecated) virtual console devices, ensure lines of this form do not appear in /etc/securetty:

vc/1
vc/2
vc/3
vc/4

Rationale:

Preventing direct root login to virtual console devices helps ensure accountability for actions taken on the system using the root account.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_securetty_root_login_console_only

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.1.1, 3.1.5
disa	CCI-000770
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	AC-6, CM-6(a)
nist-csf	PR.AC-4, PR.DS-5
os-srg	SRG-OS-000324-GPOS-00125
pcidss4	8.6.1, 8.6

Remediation Shell script ⇲

sed -i '/^vc\/[0-9]/d' /etc/securetty

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Restrict Virtual Console Root Logins
  lineinfile:
    dest: /etc/securetty
    regexp: ^vc/[0-9]
    state: absent
  tags:
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-8.6
  - PCI-DSSv4-8.6.1
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - securetty_root_login_console_only

Group Secure Session Configuration Files for Login Accounts Group contains 1 group and 19 rules

[ref] When a user logs into a Unix account, the system configures the user's session by reading a number of files. Many of these files are located in the user's home directory, and may have weak permissions as a result of user error or misconfiguration. If an attacker can modify or even read certain types of account configuration information, they can often gain full access to the affected user's account. Therefore, it is important to test and correct configuration file permissions for interactive accounts, particularly those of privileged users such as root or system administrators.

Group Ensure that Users Have Sensible Umask Values Group contains 2 rules

[ref] The umask setting controls the default permissions for the creation of new files. With a default umask setting of 077, files and directories created by users will not be readable by any other user on the system. Users who wish to make specific files group- or world-readable can accomplish this by using the chmod command. Additionally, users can make all their files readable to their group by default by setting a umask of 027 in their shell configuration files. If default per-user groups exist (that is, if every user has a default group whose name is the same as that user's username and whose only member is the user), then it may even be safe for users to select a umask of 007, making it very easy to intentionally share files with groups of which the user is a member.

Rule Ensure the Default Umask is Set Correctly in login.defs [ref]

To ensure the default umask controlled by /etc/login.defs is set properly, add or correct the UMASK setting in /etc/login.defs to read as follows:

UMASK 077

Rationale:

The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read and written to by unauthorized users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_umask_etc_login_defs

References:

cis-csc	11, 18, 3, 9
cobit5	APO13.01, BAI03.01, BAI03.02, BAI03.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05
disa	CCI-000366
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.1.1, A.14.2.1, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.5, A.6.1.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	AC-6(1), CM-6(a)
nist-csf	PR.IP-1, PR.IP-2
os-srg	SRG-OS-000480-GPOS-00228
anssi	R36

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then

var_accounts_user_umask='077'


# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^UMASK")

# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_user_umask"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^UMASK\\>" "/etc/login.defs"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^UMASK\\>.*/$escaped_formatted_output/gi" "/etc/login.defs"
else
    if [[ -s "/etc/login.defs" ]] && [[ -n "$(tail -c 1 -- "/etc/login.defs" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/login.defs"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/login.defs"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_user_umask # promote to variable
  set_fact:
    var_accounts_user_umask: !!str 077
  tags:
    - always

- name: Check if UMASK is already set
  ansible.builtin.lineinfile:
    path: /etc/login.defs
    regexp: ^(\s*)UMASK\s+.*
    state: absent
  check_mode: true
  changed_when: false
  register: result_umask_is_set
  when: '"shadow-utils" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Replace user UMASK in /etc/login.defs
  ansible.builtin.replace:
    path: /etc/login.defs
    regexp: ^(\s*)UMASK(\s+).*
    replace: \g<1>UMASK\g<2>{{ var_accounts_user_umask }}
  when:
  - '"shadow-utils" in ansible_facts.packages'
  - result_umask_is_set.found > 0
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure the Default UMASK is Appended Correctly
  ansible.builtin.lineinfile:
    create: true
    path: /etc/login.defs
    line: UMASK {{ var_accounts_user_umask }}
  when:
  - '"shadow-utils" in ansible_facts.packages'
  - result_umask_is_set.found == 0
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure the Default Umask is Set Correctly For Interactive Users [ref]

Remove the UMASK environment variable from all interactive users initialization files.

Rationale:

The umask controls the default access mode assigned to newly created files. A umask of 077 limits new files to mode 700 or less permissive. Although umask can be represented as a four-digit number, the first digit representing special access modes is typically ignored or required to be 0. This requirement applies to the globally configured system defaults and the local interactive user defaults for each account on the system.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_umask_interactive_users

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00228

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


while IFS= read -r dir; do
    while IFS= read -r -d '' file; do
        if [ "$(basename $file)" != ".bash_history" ]; then
            sed -i 's/^\(\s*umask\s*\)/#\1/g' "$file"
        fi
    done <   <(find $dir -maxdepth 1 -type f -name ".*" -print0)
done <   <(awk -F':' '{ if ($3 >= 1000 && $3 != 65534) print $6}' /etc/passwd)

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Ensure interactive local users are the owners of their respective initialization
    files
  ansible.builtin.shell:
    cmd: |-
      for dir in $(awk -F':' '{ if ($3 >= 1000 && $3 != 65534) print $6}' /etc/passwd); do
        for file in $(find $dir -maxdepth 1 -type f -name ".*"); do
          if [ "$(basename $file)" != ".bash_history" ]; then
            sed -i 's/^\(\s*umask\s*\)/#\1/g' $file
          fi
        done
      done
  tags:
  - accounts_umask_interactive_users
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure Home Directories are Created for New Users [ref]

All local interactive user accounts, upon creation, should be assigned a home directory.

Configure the operating system to assign home directories to all new local interactive users by setting the CREATE_HOME parameter in /etc/login.defs to yes as follows:

CREATE_HOME yes

Rationale:

If local interactive users are not assigned a valid home directory, there is no place for the storage and control of files they should own.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_have_homedir_login_defs

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then

if [ -e "/etc/login.defs" ] ; then
    
    LC_ALL=C sed -i "/^\s*CREATE_HOME\s\+/Id" "/etc/login.defs"
else
    touch "/etc/login.defs"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/login.defs"

cp "/etc/login.defs" "/etc/login.defs.bak"
# Insert before the line matching the regex '^\s*CREATE_HOME'.
line_number="$(LC_ALL=C grep -n "^\s*CREATE_HOME" "/etc/login.defs.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^\s*CREATE_HOME', insert at
    # the end of the file.
    printf '%s\n' "CREATE_HOME yes" >> "/etc/login.defs"
else
    head -n "$(( line_number - 1 ))" "/etc/login.defs.bak" > "/etc/login.defs"
    printf '%s\n' "CREATE_HOME yes" >> "/etc/login.defs"
    tail -n "+$(( line_number ))" "/etc/login.defs.bak" >> "/etc/login.defs"
fi
# Clean up after ourselves.
rm "/etc/login.defs.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - accounts_have_homedir_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure new users receive home directories
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/login.defs
      create: true
      regexp: (?i)^\s*CREATE_HOME\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/login.defs
    lineinfile:
      path: /etc/login.defs
      create: true
      regexp: (?i)^\s*CREATE_HOME\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/login.defs
    lineinfile:
      path: /etc/login.defs
      create: true
      regexp: (?i)^\s*CREATE_HOME\s+
      line: CREATE_HOME yes
      state: present
  when: '"shadow-utils" in ansible_facts.packages'
  tags:
  - accounts_have_homedir_login_defs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure the Logon Failure Delay is Set Correctly in login.defs [ref]

To ensure the logon failure delay controlled by /etc/login.defs is set properly, add or correct the FAIL_DELAY setting in /etc/login.defs to read as follows:

FAIL_DELAY 4

Rationale:

Increasing the time between a failed authentication attempt and re-prompting to enter credentials helps to slow a single-threaded brute force attack.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_logon_fail_delay

References:

cis-csc	11, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05
disa	CCI-000366
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4
nist	AC-7(b), CM-6(a)
nist-csf	PR.IP-1
os-srg	SRG-OS-000480-GPOS-00226

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q shadow-utils; then

var_accounts_fail_delay='4'


# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^FAIL_DELAY")

# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_fail_delay"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^FAIL_DELAY\\>" "/etc/login.defs"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^FAIL_DELAY\\>.*/$escaped_formatted_output/gi" "/etc/login.defs"
else
    if [[ -s "/etc/login.defs" ]] && [[ -n "$(tail -c 1 -- "/etc/login.defs" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/login.defs"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/login.defs"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - accounts_logon_fail_delay
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
- name: XCCDF Value var_accounts_fail_delay # promote to variable
  set_fact:
    var_accounts_fail_delay: !!str 4
  tags:
    - always

- name: Set accounts logon fail delay
  lineinfile:
    dest: /etc/login.defs
    regexp: ^FAIL_DELAY
    line: FAIL_DELAY {{ var_accounts_fail_delay }}
    create: true
  when: '"shadow-utils" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-7(b)
  - NIST-800-53-CM-6(a)
  - accounts_logon_fail_delay
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Limit the Number of Concurrent Login Sessions Allowed Per User [ref]

Limiting the number of allowed users and sessions per user can limit risks related to Denial of Service attacks. This addresses concurrent sessions for a single account and does not address concurrent sessions by a single user via multiple accounts. To set the number of concurrent sessions per user add the following line in /etc/security/limits.conf or a file under /etc/security/limits.d/:

* hard maxlogins 10

Rationale:

Limiting simultaneous user logins can insulate the system from denial of service problems caused by excessive logins. Automated login processes operating improperly or maliciously may result in an exceptional number of simultaneous login sessions.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_accounts_max_concurrent_login_sessions

References:

cis-csc	14, 15, 18, 9
cjis	5.5.2.2
cobit5	DSS01.05, DSS05.02
disa	CCI-000054
isa-62443-2009	4.3.3.4
isa-62443-2013	SR 3.1, SR 3.8
iso27001-2013	A.13.1.1, A.13.1.3, A.13.2.1, A.14.1.2, A.14.1.3
nerc-cip	CIP-007-3 R5.1, CIP-007-3 R5.1.2
nist	AC-10, CM-6(a)
nist-csf	PR.AC-5
os-srg	SRG-OS-000027-GPOS-00008

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q pam; then

var_accounts_max_concurrent_login_sessions='10'


if grep -q '^[^#]*\<maxlogins\>' /etc/security/limits.d/*.conf; then
	sed -i "/^[^#]*\<maxlogins\>/ s/maxlogins.*/maxlogins $var_accounts_max_concurrent_login_sessions/" /etc/security/limits.d/*.conf
elif grep -q '^[^#]*\<maxlogins\>' /etc/security/limits.conf; then
	sed -i "/^[^#]*\<maxlogins\>/ s/maxlogins.*/maxlogins $var_accounts_max_concurrent_login_sessions/" /etc/security/limits.conf
else
	echo "*	hard	maxlogins	$var_accounts_max_concurrent_login_sessions" >> /etc/security/limits.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.2.2
  - NIST-800-53-AC-10
  - NIST-800-53-CM-6(a)
  - accounts_max_concurrent_login_sessions
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_max_concurrent_login_sessions # promote to variable
  set_fact:
    var_accounts_max_concurrent_login_sessions: !!str 10
  tags:
    - always

- name: Find /etc/security/limits.d files containing maxlogins configuration
  find:
    paths: /etc/security/limits.d
    contains: ^[\s]*\*[\s]+(?:(?:hard)|(?:-))[\s]+maxlogins
    patterns: '*.conf'
  register: maxlogins
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.2.2
  - NIST-800-53-AC-10
  - NIST-800-53-CM-6(a)
  - accounts_max_concurrent_login_sessions
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

- name: Limit the Number of Concurrent Login Sessions Allowed Per User in files from
    limits.d
  replace:
    dest: '{{ item.path }}'
    regexp: ^#?\*.*maxlogins.*
    replace: '*          hard    maxlogins     {{ var_accounts_max_concurrent_login_sessions
      }}'
  with_items:
  - '{{ maxlogins.files }}'
  when: '"pam" in ansible_facts.packages'
  tags:
  - CJIS-5.5.2.2
  - NIST-800-53-AC-10
  - NIST-800-53-CM-6(a)
  - accounts_max_concurrent_login_sessions
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

- name: Limit the Number of Concurrent Login Sessions Allowed Per User
  lineinfile:
    state: present
    dest: /etc/security/limits.conf
    insertbefore: ^# End of file
    regexp: ^#?\*.*maxlogins
    line: '*          hard    maxlogins     {{ var_accounts_max_concurrent_login_sessions
      }}'
    create: true
  when:
  - '"pam" in ansible_facts.packages'
  - maxlogins.matched == 0
  tags:
  - CJIS-5.5.2.2
  - NIST-800-53-AC-10
  - NIST-800-53-CM-6(a)
  - accounts_max_concurrent_login_sessions
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy

Rule Set Interactive Session Timeout [ref]

Setting the TMOUT option in /etc/profile ensures that all user sessions will terminate based on inactivity. The value of TMOUT should be exported and read only. The TMOUT setting in a file loaded by /etc/profile, e.g. /etc/profile.d/tmout.sh should read as follows:

typeset -xr TMOUT=600

declare -xr TMOUT=600

Using the typeset keyword is preferred for wider compatibility with ksh and other shells.

Rationale:

Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_tmout

References:

cis-csc	1, 12, 15, 16
cobit5	DSS05.04, DSS05.10, DSS06.10
cui	3.1.11
disa	CCI-000057, CCI-001133
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nerc-cip	CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	AC-12, SC-10, AC-2(5), CM-6(a)
nist-csf	PR.AC-7
os-srg	SRG-OS-000163-GPOS-00072, SRG-OS-000029-GPOS-00010
anssi	R32
pcidss4	8.6.1, 8.6

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

var_accounts_tmout='600'


# if 0, no occurence of tmout found, if 1, occurence found
tmout_found=0


for f in /etc/profile /etc/profile.d/*.sh; do

    if grep --silent '^[^#].*TMOUT' $f; then
        sed -i -E "s/^(.*)TMOUT\s*=\s*(\w|\$)*(.*)$/typeset -xr TMOUT=$var_accounts_tmout\3/g" $f
        tmout_found=1
    fi
done

if [ $tmout_found -eq 0 ]; then
        echo -e "\n# Set TMOUT to $var_accounts_tmout per security requirements" >> /etc/profile.d/tmout.sh
        echo "typeset -xr TMOUT=$var_accounts_tmout" >> /etc/profile.d/tmout.sh
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.11
  - NIST-800-53-AC-12
  - NIST-800-53-AC-2(5)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-10
  - PCI-DSSv4-8.6
  - PCI-DSSv4-8.6.1
  - accounts_tmout
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_accounts_tmout # promote to variable
  set_fact:
    var_accounts_tmout: !!str 600
  tags:
    - always

- name: Correct any occurrence of TMOUT in /etc/profile
  replace:
    path: /etc/profile
    regexp: ^[^#].*TMOUT=.*
    replace: typeset -xr TMOUT={{ var_accounts_tmout }}
  register: profile_replaced
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.11
  - NIST-800-53-AC-12
  - NIST-800-53-AC-2(5)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-10
  - PCI-DSSv4-8.6
  - PCI-DSSv4-8.6.1
  - accounts_tmout
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set Interactive Session Timeout
  lineinfile:
    path: /etc/profile.d/tmout.sh
    create: true
    regexp: TMOUT=
    line: typeset -xr TMOUT={{ var_accounts_tmout }}
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.11
  - NIST-800-53-AC-12
  - NIST-800-53-AC-2(5)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-10
  - PCI-DSSv4-8.6
  - PCI-DSSv4-8.6.1
  - accounts_tmout
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule User Initialization Files Must Be Group-Owned By The Primary Group [ref]

Change the group owner of interactive users files to the group found in

/etc/passwd

for the user. To change the group owner of a local interactive user home directory, use the following command:

$ sudo chgrp USER_GROUP /home/USER/.INIT_FILE

This rule ensures every initialization file related to an interactive user is group-owned by an interactive user.

Warning: Due to OVAL limitation, this rule can report a false negative in a specific situation where two interactive users swap the group-ownership of their respective initialization files.

Rationale:

Local initialization files for interactive users are used to configure the user's shell environment upon logon. Malicious modification of these files could compromise accounts upon logon.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_user_dot_group_ownership

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227
anssi	R50

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


awk -F':' '{ if ($3 >= 1000 && $3 != 65534) system("chgrp -f " $4" "$6"/.[^\.]?*") }' /etc/passwd

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Ensure interactive local users are the group-owners of their respective initialization
    files
  ansible.builtin.command:
    cmd: awk -F':' '{ if ($3 >= 1000 && $3 != 65534) system("chgrp -f " $4" "$6"/.[^\.]?*")
      }' /etc/passwd
  tags:
  - accounts_user_dot_group_ownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule User Initialization Files Must Not Run World-Writable Programs [ref]

Set the mode on files being executed by the user initialization files with the following command:

$ sudo chmod o-w FILE

Rationale:

If user start-up files execute world-writable programs, especially in unprotected directories, they could be maliciously modified to destroy user files or otherwise compromise the system at the user level. If the system is compromised at the user level, it is easier to elevate privileges to eventually compromise the system at the root and network level.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_user_dot_no_world_writable_programs

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


readarray -t world_writable_files < <(find / -xdev -type f -perm -0002 2> /dev/null)
readarray -t interactive_home_dirs < <(awk -F':' '{ if ($3 >= 1000 && $3 != 65534) print $6 }' /etc/passwd)

for world_writable in "${world_writable_files[@]}"; do
    for homedir in "${interactive_home_dirs[@]}"; do
        if grep -q -d skip "$world_writable" "$homedir"/.*; then
            chmod o-w $world_writable
            break
        fi
    done
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: User Initialization Files Must Not Run World-Writable Programs - Initialize
    variables
  set_fact:
    home_user_dirs: []
    world_writable_files: []
  tags:
  - accounts_user_dot_no_world_writable_programs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: User Initialization Files Must Not Run World-Writable Programs - Get user's
    home dir list
  ansible.builtin.getent:
    database: passwd
  register: passwd_database
  tags:
  - accounts_user_dot_no_world_writable_programs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: User Initialization Files Must Not Run World-Writable Programs - Fill home_user_dirs
  set_fact:
    home_user_dirs: '{{ home_user_dirs + [item.data[4]] }}'
  when: item.data[4] is defined and item.data[2]|int >= 1000 and item.data[2]|int
    != 65534
  with_items: '{{ passwd_database.ansible_facts.getent_passwd | dict2items(key_name=''user'',
    value_name=''data'')}}'
  tags:
  - accounts_user_dot_no_world_writable_programs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: User Initialization Files Must Not Run World-Writable Programs - Get world
    writable files
  ansible.builtin.shell: |
    find / -xdev -type f -perm -0002 2> /dev/null
  register: world_writable_files
  tags:
  - accounts_user_dot_no_world_writable_programs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: User Initialization Files Must Not Run World-Writable Programs - Find referenced_files
    in init files
  ansible.builtin.find:
    paths: '{{ home_user_dirs }}'
    contains: '{{ item }}'
    hidden: true
    read_whole_file: true
    recurse: true
  with_items: '{{ world_writable_files.stdout_lines }}'
  register: referenced_files
  tags:
  - accounts_user_dot_no_world_writable_programs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: User Initialization Files Must Not Run World-Writable Programs - Remove world
    writable permissions
  ansible.builtin.file:
    path: '{{ item.item }}'
    mode: o-w
  when: item.matched > 0
  with_items: '{{ referenced_files.results }}'
  tags:
  - accounts_user_dot_no_world_writable_programs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule User Initialization Files Must Be Owned By the Primary User [ref]

Set the owner of the user initialization files for interactive users to the primary owner with the following command:

$ sudo chown USER /home/USER/.*

This rule ensures every initialization file related to an interactive user is owned by an interactive user.

Warning: Due to OVAL limitation, this rule can report a false negative in a specific situation where two interactive users swap the ownership of their respective initialization files.

Rationale:

Local initialization files are used to configure the user's shell environment upon logon. Malicious modification of these files could compromise accounts upon logon.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_user_dot_user_ownership

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227
anssi	R50

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


awk -F':' '{ if ($3 >= 1000 && $3 != 65534) system("chown -f " $3" "$6"/.[^\.]?*") }' /etc/passwd

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Ensure interactive local users are the owners of their respective initialization
    files
  ansible.builtin.command:
    cmd: awk -F':' '{ if ($3 >= 1000 && $3 != 65534) system("chown -f " $3" "$6"/.[^\.]?*")
      }' /etc/passwd
  tags:
  - accounts_user_dot_user_ownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure that Users Path Contains Only Local Directories [ref]

Ensure that all interactive user initialization files executable search path statements do not contain statements that will reference a working directory other than the users home directory.

Rationale:

The executable search path (typically the PATH environment variable) contains a list of directories for the shell to search to find executables. If this path includes the current working directory (other than the users home directory), executables in these directories may be executed instead of system commands. This variable is formatted as a colon-separated list of directories. If there is an empty entry, such as a leading or trailing colon or two consecutive colons, this is interpreted as the current working directory. If deviations from the default system search path for the local interactive user are required, they must be documented with the Information System Security Officer (ISSO).

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_accounts_user_home_paths_only

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Rule All Interactive Users Must Have A Home Directory Defined [ref]

Assign home directories to all interactive users that currently do not have a home directory assigned. This rule checks if the home directory is properly defined in a folder which has at least one parent folder, like "user" in "/home/user" or "/remote/users/user". Therefore, this rule will report a finding for home directories like /users, /tmp or /.

Rationale:

If local interactive users are not assigned a valid home directory, there is no place for the storage and control of files they should own.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_user_interactive_home_directory_defined

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


for user in $(awk -F':' '{ if ($3 >= 1000 && $3 != 65534) print $1 }' /etc/passwd); do
    # This follows the same logic of evaluation of home directories as used in OVAL.
    if ! grep -q $user /etc/passwd | cut -d: -f6 | grep '^\/\w*\/\w\{1,\}'; then
        sed -i "s/\($user:x:[0-9]*:[0-9]*:.*:\).*\(:.*\)$/\1\/home\/$user\2/g" /etc/passwd;
    fi
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Get all local users from /etc/passwd
  ansible.builtin.getent:
    database: passwd
    split: ':'
  tags:
  - accounts_user_interactive_home_directory_defined
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Create local_users variable from the getent output
  ansible.builtin.set_fact:
    local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
  tags:
  - accounts_user_interactive_home_directory_defined
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure interactive users have an exclusive home directory defined
  ansible.builtin.user:
    name: '{{ item.key }}'
    home: /home/{{ item.key }}
    create_home: false
  loop: '{{ local_users }}'
  when:
  - item.value[2]|int >= 1000
  - item.value[2]|int != 65534
  - item.value[2]|int < 61184 or item.value[2]|int > 65519
  - not item.value[4] | regex_search('^\/\w*\/\w{1,}')
  tags:
  - accounts_user_interactive_home_directory_defined
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule All Interactive Users Home Directories Must Exist [ref]

Create home directories to all local interactive users that currently do not have a home directory assigned. Use the following commands to create the user home directory assigned in /etc/passwd:

$ sudo mkdir /home/USER

Rationale:

If a local interactive user has a home directory defined that does not exist, the user may be given access to the / directory as the current working directory upon logon. This could create a Denial of Service because the user would not be able to access their logon configuration files, and it may give them visibility to system files they normally would not be able to access.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_user_interactive_home_directory_exists

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


for user in $(awk -F':' '{ if ($3 >= 1000 && $3 != 65534) print $1}' /etc/passwd); do
    mkhomedir_helper $user 0077;
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Get all local users from /etc/passwd
  ansible.builtin.getent:
    database: passwd
    split: ':'
  tags:
  - accounts_user_interactive_home_directory_exists
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Create local_users variable from the getent output
  ansible.builtin.set_fact:
    local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
  tags:
  - accounts_user_interactive_home_directory_exists
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure interactive users have a home directory exists
  ansible.builtin.user:
    name: '{{ item.key }}'
    create_home: true
  loop: '{{ local_users }}'
  when:
  - item.value[2]|int >= 1000
  - item.value[2]|int != 65534
  tags:
  - accounts_user_interactive_home_directory_exists
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule All User Files and Directories In The Home Directory Must Be Group-Owned By The Primary Group [ref]

Change the group of a local interactive users files and directories to a group that the interactive user is a member of. To change the group owner of a local interactive users files and directories, use the following command:

$ sudo chgrp USER_GROUP /home/USER/FILE_DIR

This rule ensures every file or directory under the home directory related to an interactive user is group-owned by an interactive user.

Warning: Due to OVAL limitation, this rule can report a false negative in a specific situation where two interactive users swap the group-ownership of folders or files in their respective home directories.

Rationale:

If a local interactive users files are group-owned by a group of which the user is not a member, unintended users may be able to access them.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_users_home_files_groupownership

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227
anssi	R50

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


for user in $(awk -F':' '{ if ($3 >= 1000 && $3 != 65534 && $6 != "/") print $1 }' /etc/passwd); do
    home_dir=$(getent passwd $user | cut -d: -f6)
    group=$(getent passwd $user | cut -d: -f4)
    # Only update the group-ownership when necessary. This will avoid changing the inode timestamp
    # when the group is already defined as expected, therefore not impacting in possible integrity
    # check systems that also check inodes timestamps.
    find $home_dir -not -group $group -exec chgrp -f --no-dereference $group {} \;
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Get all local users from /etc/passwd
  ansible.builtin.getent:
    database: passwd
    split: ':'
  tags:
  - accounts_users_home_files_groupownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Create local_users variable from the getent output
  ansible.builtin.set_fact:
    local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
  tags:
  - accounts_users_home_files_groupownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Test for existence of home directories to avoid creating them, but only fixing
    ownership
  ansible.builtin.stat:
    path: '{{ item.value[4] }}'
  register: path_exists
  loop: '{{ local_users }}'
  when:
  - item.value[1]|int >= 1000
  - item.value[1]|int != 65534
  - item.value[4] != "/"
  tags:
  - accounts_users_home_files_groupownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure interactive local users are the owners of their respective home directories
  ansible.builtin.file:
    path: '{{ item.0.value[4] }}'
    group: '{{ item.0.value[2] }}'
    recurse: true
  loop: '{{ local_users|zip(path_exists.results)|list }}'
  when: item.1.stat is defined and item.1.stat.exists
  tags:
  - accounts_users_home_files_groupownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule All User Files and Directories In The Home Directory Must Have a Valid Owner [ref]

Either remove all files and directories from the system that do not have a valid user, or assign a valid user to all unowned files and directories. To assign a valid owner to a local interactive user's files and directories, use the following command:

$ sudo chown -R USER /home/USER

This rule ensures every file or directory under the home directory related to an interactive user is owned by an interactive user.

Warning: Due to OVAL limitation, this rule can report a false negative in a specific situation where two interactive users swap the ownership of folders or files in their respective home directories.

Rationale:

If local interactive users do not own the files in their directories, unauthorized users may be able to access them. Additionally, if files are not owned by the user, this could be an indication of system compromise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_users_home_files_ownership

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227
anssi	R50

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


for user in $(awk -F':' '{ if ($3 >= 1000 && $3 != 65534 && $6 != "/") print $1 }' /etc/passwd); do
    home_dir=$(getent passwd $user | cut -d: -f6)
    # Only update the ownership when necessary. This will avoid changing the inode timestamp
    # when the owner is already defined as expected, therefore not impacting in possible integrity
    # check systems that also check inodes timestamps.
    find $home_dir -not -user $user -exec chown -f --no-dereference $user {} \;
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Get all local users from /etc/passwd
  ansible.builtin.getent:
    database: passwd
    split: ':'
  tags:
  - accounts_users_home_files_ownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Create local_users variable from the getent output
  ansible.builtin.set_fact:
    local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
  tags:
  - accounts_users_home_files_ownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Test for existence of home directories to avoid creating them, but only fixing
    ownership
  ansible.builtin.stat:
    path: '{{ item.value[4] }}'
  register: path_exists
  loop: '{{ local_users }}'
  when:
  - item.value[1]|int >= 1000
  - item.value[1]|int != 65534
  - item.value[4] != "/"
  tags:
  - accounts_users_home_files_ownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure interactive local users are the owners of their respective home directories
  ansible.builtin.file:
    path: '{{ item.0.value[4] }}'
    owner: '{{ item.0.value[1] }}'
    recurse: true
  loop: '{{ local_users|zip(path_exists.results)|list }}'
  when: item.1.stat is defined and item.1.stat.exists
  tags:
  - accounts_users_home_files_ownership
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule All User Files and Directories In The Home Directory Must Have Mode 0750 Or Less Permissive [ref]

Set the mode on files and directories in the local interactive user home directory with the following command:

$ sudo chmod 0750 /home/USER/FILE_DIR

Files that begin with a "." are excluded from this requirement.

Rationale:

If a local interactive user files have excessive permissions, unintended users may be able to access or modify them.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_users_home_files_permissions

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227
anssi	R50

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


for home_dir in $(awk -F':' '{ if ($3 >= 1000 && $3 != 65534 && $6 != "/") print $6 }' /etc/passwd); do
    # Only update the permissions when necessary. This will avoid changing the inode timestamp when
    # the permission is already defined as expected, therefore not impacting in possible integrity
    # check systems that also check inodes timestamps.
    find "$home_dir" -perm /7027 \! -type l -exec chmod u-s,g-w-s,o=- {} \;
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Get all local users from /etc/passwd
  ansible.builtin.getent:
    database: passwd
    split: ':'
  tags:
  - accounts_users_home_files_permissions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Create local_users variable from the getent output
  ansible.builtin.set_fact:
    local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
  tags:
  - accounts_users_home_files_permissions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Test for existence home directories to avoid creating them.
  ansible.builtin.stat:
    path: '{{ item.value[4] }}'
  register: path_exists
  loop: '{{ local_users }}'
  when:
  - item.value[1]|int >= 1000
  - item.value[1]|int != 65534
  - item.value[4] != "/"
  tags:
  - accounts_users_home_files_permissions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure interactive local users have proper permissions on their respective
    home directories
  ansible.builtin.file:
    path: '{{ item.0.value[4] }}'
    mode: u-s,g-w-s,o=-
    follow: false
    recurse: true
  loop: '{{ local_users|zip(path_exists.results)|list }}'
  when: item.1.stat is defined and item.1.stat.exists
  tags:
  - accounts_users_home_files_permissions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule All Interactive User Home Directories Must Be Group-Owned By The Primary Group [ref]

Change the group owner of interactive users home directory to the group found in /etc/passwd. To change the group owner of interactive users home directory, use the following command:

$ sudo chgrp USER_GROUP /home/USER

This rule ensures every home directory related to an interactive user is group-owned by an interactive user. It also ensures that interactive users are group-owners of one and only one home directory.

Warning: Due to OVAL limitation, this rule can report a false negative in a specific situation where two interactive users swap the group-ownership of their respective home directories.

Rationale:

If the Group Identifier (GID) of a local interactive users home directory is not the same as the primary GID of the user, this would allow unauthorized access to the users files, and users that share the same group may not be able to access files that they legitimately should.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_groupownership_home_directories

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


awk -F':' '{ if ($3 >= 1000 && $3 != 65534) system("chgrp -f " $4" "$6) }' /etc/passwd

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Get all local users from /etc/passwd
  ansible.builtin.getent:
    database: passwd
    split: ':'
  tags:
  - file_groupownership_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Create local_users variable from the getent output
  ansible.builtin.set_fact:
    local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
  tags:
  - file_groupownership_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Test for existence of home directories to avoid creating them, but only fixing
    group ownership
  ansible.builtin.stat:
    path: '{{ item.value[4] }}'
  register: path_exists
  loop: '{{ local_users }}'
  when:
  - item.value[1]|int >= 1000
  - item.value[1]|int != 65534
  tags:
  - file_groupownership_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure interactive local users are the group-owners of their respective home
    directories
  ansible.builtin.file:
    path: '{{ item.0.value[4] }}'
    group: '{{ item.0.value[2] }}'
  loop: '{{ local_users|zip(path_exists.results)|list }}'
  when: item.1.stat is defined and item.1.stat.exists
  tags:
  - file_groupownership_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule All Interactive User Home Directories Must Be Owned By The Primary User [ref]

Change the owner of interactive users home directories to that correct owner. To change the owner of a interactive users home directory, use the following command:

$ sudo chown USER /home/USER

This rule ensures every home directory related to an interactive user is owned by an interactive user. It also ensures that interactive users are owners of one and only one home directory.

Warning: Due to OVAL limitation, this rule can report a false negative in a specific situation where two interactive users swap the ownership of their respective home directories.

Rationale:

If a local interactive user does not own their home directory, unauthorized users could access or modify the user's files, and the users may not be able to access their own files.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_ownership_home_directories

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


awk -F':' '{ if ($3 >= 1000 && $3 != 65534) system("chown -f " $3" "$6) }' /etc/passwd

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Get all local users from /etc/passwd
  ansible.builtin.getent:
    database: passwd
    split: ':'
  tags:
  - file_ownership_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Create local_users variable from the getent output
  ansible.builtin.set_fact:
    local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
  tags:
  - file_ownership_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Test for existence of home directories to avoid creating them, but only fixing
    ownership
  ansible.builtin.stat:
    path: '{{ item.value[4] }}'
  register: path_exists
  loop: '{{ local_users }}'
  when:
  - item.value[1]|int >= 1000
  - item.value[1]|int != 65534
  tags:
  - file_ownership_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure interactive local users are the owners of their respective home directories
  ansible.builtin.file:
    path: '{{ item.0.value[4] }}'
    owner: '{{ item.0.value[1] }}'
  loop: '{{ local_users|zip(path_exists.results)|list }}'
  when: item.1.stat is defined and item.1.stat.exists
  tags:
  - file_ownership_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure All User Initialization Files Have Mode 0740 Or Less Permissive [ref]

Set the mode of the user initialization files to 0740 with the following command:

$ sudo chmod 0740 /home/USER/.INIT_FILE

Rationale:

Local initialization files are used to configure the user's shell environment upon logon. Malicious modification of these files could compromise accounts upon logon.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permission_user_init_files

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227
anssi	R50

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


var_user_initialization_files_regex='^(\.bashrc|\.zshrc|\.cshrc|\.profile|\.bash_login|\.bash_profile)$'


readarray -t interactive_users < <(awk -F: '$3>=1000   {print $1}' /etc/passwd)
readarray -t interactive_users_home < <(awk -F: '$3>=1000   {print $6}' /etc/passwd)
readarray -t interactive_users_shell < <(awk -F: '$3>=1000   {print $7}' /etc/passwd)

USERS_IGNORED_REGEX='nobody|nfsnobody'

for (( i=0; i<"${#interactive_users[@]}"; i++ )); do
    if ! grep -qP "$USERS_IGNORED_REGEX" <<< "${interactive_users[$i]}" && \
        [ "${interactive_users_shell[$i]}" != "/sbin/nologin" ]; then
        
        readarray -t init_files < <(find "${interactive_users_home[$i]}" -maxdepth 1 \
            -exec basename {} \; | grep -P "$var_user_initialization_files_regex")
        for file in "${init_files[@]}"; do
            chmod u-s,g-wxs,o= "${interactive_users_home[$i]}/$file"
        done
    fi
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: XCCDF Value var_user_initialization_files_regex # promote to variable
  set_fact:
    var_user_initialization_files_regex: !!str ^(\.bashrc|\.zshrc|\.cshrc|\.profile|\.bash_login|\.bash_profile)$
  tags:
    - always

- name: Ensure All User Initialization Files Have Mode 0740 Or Less Permissive - Gather
    User Info
  ansible.builtin.getent:
    database: passwd
  tags:
  - file_permission_user_init_files
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure All User Initialization Files Have Mode 0740 Or Less Permissive - Find
    Init Files
  ansible.builtin.find:
    paths: '{{ item.value[4] }}'
    pattern: '{{ var_user_initialization_files_regex }}'
    hidden: true
    use_regex: true
  with_dict: '{{ ansible_facts.getent_passwd }}'
  when:
  - item.value[4] != "/sbin/nologin"
  - item.key not in ["nobody", "nfsnobody"]
  - item.value[1] | int >= 1000
  register: found_init_files
  tags:
  - file_permission_user_init_files
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure All User Initialization Files Have Mode 0740 Or Less Permissive - Fix
    Init Files Permissions
  ansible.builtin.file:
    path: '{{ item.1.path }}'
    mode: u-s,g-wxs,o=
  loop: '{{ q(''ansible.builtin.subelements'', found_init_files.results, ''files'',
    {''skip_missing'': True}) }}'
  tags:
  - file_permission_user_init_files
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule All Interactive User Home Directories Must Have mode 0750 Or Less Permissive [ref]

Change the mode of interactive users home directories to 0750. To change the mode of interactive users home directory, use the following command:

$ sudo chmod 0750 /home/USER

Rationale:

Excessive permissions on local interactive user home directories may allow unauthorized access to user files by other users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permissions_home_directories

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict


for home_dir in $(awk -F':' '{ if ($3 >= 1000 && $3 != 65534 && $6 != "/") print $6 }' /etc/passwd); do
    # Only update the permissions when necessary. This will avoid changing the inode timestamp when
    # the permission is already defined as expected, therefore not impacting in possible integrity
    # check systems that also check inodes timestamps.
    find "$home_dir" -maxdepth 0 -perm /7027 \! -type l -exec chmod u-s,g-w-s,o=- {} \;
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Get all local users from /etc/passwd
  ansible.builtin.getent:
    database: passwd
    split: ':'
  tags:
  - file_permissions_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Create local_users variable from the getent output
  ansible.builtin.set_fact:
    local_users: '{{ ansible_facts.getent_passwd|dict2items }}'
  tags:
  - file_permissions_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Test for existence home directories to avoid creating them.
  ansible.builtin.stat:
    path: '{{ item.value[4] }}'
  register: path_exists
  loop: '{{ local_users }}'
  when:
  - item.value[1]|int >= 1000
  - item.value[1]|int != 65534
  - item.value[4] != "/"
  tags:
  - file_permissions_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure interactive local users have proper permissions on their respective
    home directories
  ansible.builtin.file:
    path: '{{ item.0.value[4] }}'
    mode: u-s,g-w-s,o=-
    follow: false
    recurse: false
  loop: '{{ local_users|zip(path_exists.results)|list }}'
  when: item.1.stat is defined and item.1.stat.exists
  tags:
  - file_permissions_home_directories
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Group GRUB2 bootloader configuration Group contains 2 groups and 6 rules

[ref] During the boot process, the boot loader is responsible for starting the execution of the kernel and passing options to it. The boot loader allows for the selection of different kernels - possibly on different partitions or media. The default Red Hat Virtualization 4 boot loader for x86 systems is called GRUB2. Options it can pass to the kernel include single-user mode, which provides root access without any authentication, and the ability to disable SELinux. To prevent local users from modifying the boot parameters and endangering security, protect the boot loader configuration with a password and ensure its configuration file's permissions are set properly.

Group Non-UEFI GRUB2 bootloader configuration Group contains 5 rules

[ref] Non-UEFI GRUB2 bootloader configuration

Rule Verify /boot/grub2/grub.cfg Group Ownership [ref]

The file /boot/grub2/grub.cfg should be group-owned by the root group to prevent destruction or modification of the file. To properly set the group owner of /boot/grub2/grub.cfg, run the command:

$ sudo chgrp root /boot/grub2/grub.cfg

Rationale:

The root group is a highly-privileged group. Furthermore, the group-owner of this file should not have any access privileges anyway.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_groupowner_grub2_cfg

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cjis	5.5.2.2
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.4.5
disa	CCI-000366
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.DS-5
pcidss	Req-7.1
os-srg	SRG-OS-000480-GPOS-00227
anssi	R29
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if [ ! -d /sys/firmware/efi ] && rpm --quiet -q grub2-common && { rpm --quiet -q kernel; }; then

chgrp 0 /boot/grub2/grub.cfg

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.2.2
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-7.1
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_grub2_cfg
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Test for existence /boot/grub2/grub.cfg
  stat:
    path: /boot/grub2/grub.cfg
  register: file_exists
  when:
  - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
  - '"grub2-common" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.2.2
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-7.1
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_grub2_cfg
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure group owner 0 on /boot/grub2/grub.cfg
  file:
    path: /boot/grub2/grub.cfg
    group: '0'
  when:
  - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
  - '"grub2-common" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - file_exists.stat is defined and file_exists.stat.exists
  tags:
  - CJIS-5.5.2.2
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-7.1
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_grub2_cfg
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Verify /boot/grub2/grub.cfg User Ownership [ref]

The file /boot/grub2/grub.cfg should be owned by the root user to prevent destruction or modification of the file. To properly set the owner of /boot/grub2/grub.cfg, run the command:

$ sudo chown root /boot/grub2/grub.cfg

Rationale:

Only root should be able to modify important boot parameters.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_owner_grub2_cfg

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cjis	5.5.2.2
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.4.5
disa	CCI-000366
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.DS-5
pcidss	Req-7.1
os-srg	SRG-OS-000480-GPOS-00227
anssi	R29
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if [ ! -d /sys/firmware/efi ] && rpm --quiet -q grub2-common && { rpm --quiet -q kernel; }; then

chown 0 /boot/grub2/grub.cfg

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.2.2
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-7.1
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_owner_grub2_cfg
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Test for existence /boot/grub2/grub.cfg
  stat:
    path: /boot/grub2/grub.cfg
  register: file_exists
  when:
  - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
  - '"grub2-common" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.2.2
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-7.1
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_owner_grub2_cfg
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure owner 0 on /boot/grub2/grub.cfg
  file:
    path: /boot/grub2/grub.cfg
    owner: '0'
  when:
  - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
  - '"grub2-common" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - file_exists.stat is defined and file_exists.stat.exists
  tags:
  - CJIS-5.5.2.2
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-7.1
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_owner_grub2_cfg
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Verify /boot/grub2/grub.cfg Permissions [ref]

File permissions for /boot/grub2/grub.cfg should be set to 600. To properly set the permissions of /boot/grub2/grub.cfg, run the command:

$ sudo chmod 600 /boot/grub2/grub.cfg

Rationale:

Proper permissions ensure that only the root user can modify important boot parameters.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permissions_grub2_cfg

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.4.5
disa	CCI-000225
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.DS-5
anssi	R29
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if [ ! -d /sys/firmware/efi ] && rpm --quiet -q grub2-common && { rpm --quiet -q kernel; }; then

chmod u-xs,g-xwrs,o-xwrt /boot/grub2/grub.cfg

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_permissions_grub2_cfg
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Test for existence /boot/grub2/grub.cfg
  stat:
    path: /boot/grub2/grub.cfg
  register: file_exists
  when:
  - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
  - '"grub2-common" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_permissions_grub2_cfg
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure permission u-xs,g-xwrs,o-xwrt on /boot/grub2/grub.cfg
  file:
    path: /boot/grub2/grub.cfg
    mode: u-xs,g-xwrs,o-xwrt
  when:
  - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
  - '"grub2-common" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - file_exists.stat is defined and file_exists.stat.exists
  tags:
  - NIST-800-171-3.4.5
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_permissions_grub2_cfg
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Boot Loader Is Not Installed On Removeable Media [ref]

The system must not allow removable media to be used as the boot loader. Remove alternate methods of booting the system from removable media. usb0, cd, fd0, etc. are some examples of removeable media which should not exist in the lines:

set root='hd0,msdos1'

Rationale:

Malicious users with removable boot media can gain access to a system configured to use removable media as the boot loader.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_grub2_no_removeable_media

References:

disa	CCI-001813, CCI-003938
os-srg	SRG-OS-000364-GPOS-00151

Rule Set Boot Loader Password in grub2 [ref]

The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.

Since plaintext passwords are a security risk, generate a hash for the password by running the following command:

# grub2-setpassword

When prompted, enter the password that was selected.

Warning: To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation must be automated as a component of machine provisioning, or followed manually as outlined above. Also, do NOT manually add the superuser account and password to the grub.cfg file as the grub2-mkconfig command overwrites this file.

Rationale:

Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_grub2_password

References:

cis-csc	1, 11, 12, 14, 15, 16, 18, 3, 5
cobit5	DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10
cui	3.4.5
disa	CCI-000213
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7
iso27001-2013	A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nist	CM-6(a)
nist-csf	PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3
os-srg	SRG-OS-000080-GPOS-00048
anssi	R5

Group UEFI GRUB2 bootloader configuration Group contains 1 rule

[ref] UEFI GRUB2 bootloader configuration

Warning: UEFI generally uses vfat file systems, which does not support Unix-style permissions managed by chmod command. In this case, in order to change file permissions for files within /boot/efi it is necessary to update the mount options in /etc/fstab file and reboot the system.

Rule Set the UEFI Boot Loader Password [ref]

# grub2-setpassword

When prompted, enter the password that was selected.

Rationale:

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_grub2_uefi_password

References:

cis-csc	11, 12, 14, 15, 16, 18, 3, 5
cobit5	DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06
cui	3.4.5
disa	CCI-000213
hipaa	164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7
iso27001-2013	A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a)
nist-csf	PR.AC-4, PR.AC-6, PR.PT-3
ospp	FIA_UAU.1
os-srg	SRG-OS-000080-GPOS-00048
anssi	R5

Group Configure Syslog Group contains 3 groups and 3 rules

[ref] The syslog service has been the default Unix logging mechanism for many years. It has a number of downsides, including inconsistent log format, lack of authentication for received messages, and lack of authentication, encryption, or reliable transport for messages sent over a network. However, due to its long history, syslog is a de facto standard which is supported by almost all Unix applications.

In Red Hat Virtualization 4, rsyslog has replaced ksyslogd as the syslog daemon of choice, and it includes some additional security features such as reliable, connection-oriented (i.e. TCP) transmission of logs, the option to log to database formats, and the encryption of log data en route to a central logging server. This section discusses how to configure rsyslog for best effect, and how to use tools provided with the system to maintain and monitor logs.

Group Ensure Proper Configuration of Log Files Group contains 1 rule

[ref] The file /etc/rsyslog.conf controls where log message are written. These are controlled by lines called rules, which consist of a selector and an action. These rules are often customized depending on the role of the system, the requirements of the environment, and whatever may enable the administrator to most effectively make use of log data. The default rules in Red Hat Virtualization 4 are:

*.info;mail.none;authpriv.none;cron.none                /var/log/messages
authpriv.*                                              /var/log/secure
mail.*                                                  -/var/log/maillog
cron.*                                                  /var/log/cron
*.emerg                                                 *
uucp,news.crit                                          /var/log/spooler
local7.*                                                /var/log/boot.log

See the man page rsyslog.conf(5) for more information. Note that the rsyslog daemon can be configured to use a timestamp format that some log processing programs may not understand. If this occurs, edit the file /etc/rsyslog.conf and add or edit the following line:

$ ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat

Rule Ensure cron Is Logging To Rsyslog [ref]

Cron logging must be implemented to spot intrusions or trace cron job status. If cron is not logging to rsyslog, it can be implemented by adding the following to the RULES section of /etc/rsyslog.conf: If the legacy syntax is used:

cron.*                                                  /var/log/cron

If the modern syntax (RainerScript) is used:

cron.* action(type="omfile" file="/var/log/cron")

Rationale:

Cron logging can be used to trace the successful or unsuccessful execution of cron jobs. It can also be used to spot intrusions into the use of the cron facility by unauthorized and malicious users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_rsyslog_cron_logging

References:

cis-csc	1, 14, 15, 16, 3, 5, 6
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
disa	CCI-000366
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1
ism	0988, 1405
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.15.2.1, A.15.2.2
nist	CM-6(a)
nist-csf	ID.SC-4, PR.PT-1
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && rpm --quiet -q rsyslog; then

if ! grep -s "^\s*cron\.\*\s*/var/log/cron$" /etc/rsyslog.conf /etc/rsyslog.d/*.conf; then
	mkdir -p /etc/rsyslog.d
	echo "cron.*	/var/log/cron" >> /etc/rsyslog.d/cron.conf
fi

if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    systemctl restart rsyslog.service
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_cron_logging

- name: Ensure cron Is Logging To Rsyslog - Search if cron configuration exists
  ansible.builtin.command: grep -s "^\s*cron\.\*\s*/var/log/cron$" /etc/rsyslog.conf
    /etc/rsyslog.d/*.conf
  register: cron_log_config_exists
  failed_when: false
  when:
  - '"kernel" in ansible_facts.packages'
  - '"rsyslog" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_cron_logging

- name: Ensure cron Is Logging To Rsyslog - Ensure the /etc/rsyslog.d directory exists
  ansible.builtin.file:
    path: /etc/rsyslog.d
    state: directory
  when:
  - '"kernel" in ansible_facts.packages'
  - '"rsyslog" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_cron_logging

- name: Ensure cron Is Logging To Rsyslog - Add cron log configuration line
  ansible.builtin.lineinfile:
    path: /etc/rsyslog.d/cron.conf
    line: cron.*  /var/log/cron
    create: true
  when:
  - '"kernel" in ansible_facts.packages'
  - '"rsyslog" in ansible_facts.packages'
  - cron_log_config_exists.stdout_lines | length == 0
  tags:
  - NIST-800-53-CM-6(a)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_cron_logging

- name: Ensure cron Is Logging To Rsyslog - Restart the rsyslog service now
  ansible.builtin.service:
    name: rsyslog
    state: restarted
  when:
  - '"kernel" in ansible_facts.packages'
  - '"rsyslog" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_cron_logging

Group Configure rsyslogd to Accept Remote Messages If Acting as a Log Server Group contains 1 rule

[ref] By default, rsyslog does not listen over the network for log messages. If needed, modules can be enabled to allow the rsyslog daemon to receive messages from other systems and for the system thus to act as a log server. If the system is not a log server, then lines concerning these modules should remain commented out.

Rule Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server [ref]

The rsyslog daemon should not accept remote messages unless the system acts as a log server. To ensure that it is not listening on the network, ensure any of the following lines are not found in rsyslog configuration files. If using legacy syntax:

$ModLoad imtcp
$InputTCPServerRun port
$ModLoad imudp
$UDPServerRun port
$ModLoad imrelp
$InputRELPServerRun port

If using RainerScript syntax:

module(load="imtcp")
module(load="imudp")
input(type="imtcp" port="514")
input(type="imudp" port="514")

Rationale:

Any process which receives messages from the network incurs some risk of receiving malicious messages. This risk can be eliminated for rsyslog by configuring it not to listen on the network.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_rsyslog_nolisten

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9
cobit5	APO01.06, APO11.04, APO13.01, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, MEA02.01
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.8, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
ism	0988, 1405
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.IP-1, PR.PT-1, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

legacy_regex='^\s*\$(((Input(TCP|RELP)|UDP)ServerRun)|ModLoad\s+(imtcp|imudp|imrelp))'
rainer_regex='^\s*(module|input)\((load|type)="(imtcp|imudp)".*$'

readarray -t legacy_targets < <(grep -l -E -r "${legacy_regex[@]}" /etc/rsyslog.conf /etc/rsyslog.d/)
readarray -t rainer_targets < <(grep -l -E -r "${rainer_regex[@]}" /etc/rsyslog.conf /etc/rsyslog.d/)

config_changed=false
if [ ${#legacy_targets[@]} -gt 0 ]; then
    for target in "${legacy_targets[@]}"; do
        sed -E -i "/$legacy_regex/ s/^/# /" "$target"
    done
    config_changed=true
fi

if [ ${#rainer_targets[@]} -gt 0 ]; then
    for target in "${rainer_targets[@]}"; do
        sed -E -i "/$rainer_regex/ s/^/# /" "$target"
    done
    config_changed=true
fi

if $config_changed; then
    systemctl restart rsyslog.service
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Define Rsyslog Config Lines Regex in Legacy Syntax
  ansible.builtin.set_fact:
    rsyslog_listen_legacy_regex: ^\s*\$(((Input(TCP|RELP)|UDP)ServerRun)|ModLoad\s+(imtcp|imudp|imrelp))
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Search for Legacy Config Lines in Rsyslog Main Config File
  ansible.builtin.find:
    paths: /etc
    pattern: rsyslog.conf
    contains: '{{ rsyslog_listen_legacy_regex }}'
  register: rsyslog_listen_legacy_main_file
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Search for Legacy Config Lines in Rsyslog Include Files
  ansible.builtin.find:
    paths: /etc/rsyslog.d/
    pattern: '*.conf'
    contains: '{{ rsyslog_listen_legacy_regex }}'
  register: rsyslog_listen_legacy_include_files
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Assemble List of Config Files With Listen Lines in Legacy Syntax
  ansible.builtin.set_fact:
    rsyslog_legacy_remote_listen_files: '{{ rsyslog_listen_legacy_main_file.files
      | map(attribute=''path'') | list + rsyslog_listen_legacy_include_files.files
      | map(attribute=''path'') | list }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Comment Listen Config Lines Wherever Defined Using Legacy Syntax
  ansible.builtin.replace:
    path: '{{ item }}'
    regexp: '{{ rsyslog_listen_legacy_regex }}'
    replace: '# \1'
  loop: '{{ rsyslog_legacy_remote_listen_files }}'
  register: rsyslog_listen_legacy_comment
  when:
  - '"kernel" in ansible_facts.packages'
  - rsyslog_legacy_remote_listen_files | length > 0
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Define Rsyslog Config Lines Regex in RainerScript Syntax
  ansible.builtin.set_fact:
    rsyslog_listen_rainer_regex: ^\s*(module|input)\((load|type)="(imtcp|imudp)".*$
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Search for RainerScript Config Lines in Rsyslog Main Config File
  ansible.builtin.find:
    paths: /etc
    pattern: rsyslog.conf
    contains: '{{ rsyslog_listen_rainer_regex }}'
  register: rsyslog_rainer_remote_main_file
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Search for RainerScript Config Lines in Rsyslog Include Files
  ansible.builtin.find:
    paths: /etc/rsyslog.d/
    pattern: '*.conf'
    contains: '{{ rsyslog_listen_rainer_regex }}'
  register: rsyslog_rainer_remote_include_files
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Assemble List of Config Files With Listen Lines in RainerScript
  ansible.builtin.set_fact:
    rsyslog_rainer_remote_listen_files: '{{ rsyslog_rainer_remote_main_file.files
      | map(attribute=''path'') | list + rsyslog_rainer_remote_include_files.files
      | map(attribute=''path'') | list }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Comment Listen Config Lines Wherever Defined Using RainerScript
  ansible.builtin.replace:
    path: '{{ item }}'
    regexp: '{{ rsyslog_listen_rainer_regex }}'
    replace: '# \1'
  loop: '{{ rsyslog_rainer_remote_listen_files }}'
  register: rsyslog_listen_rainer_comment
  when:
  - '"kernel" in ansible_facts.packages'
  - rsyslog_rainer_remote_listen_files | length > 0
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

- name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
    - Restart Rsyslog if Any Line Were Commented Out
  ansible.builtin.service:
    name: rsyslog
    state: restarted
  when:
  - '"kernel" in ansible_facts.packages'
  - rsyslog_listen_legacy_comment is changed or rsyslog_listen_rainer_comment is changed
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_nolisten

Group Rsyslog Logs Sent To Remote Host Group contains 1 rule

[ref] If system logs are to be useful in detecting malicious activities, it is necessary to send logs to a remote server. An intruder who has compromised the root account on a system may delete the log entries which indicate that the system was attacked before they are seen by an administrator.

However, it is recommended that logs be stored on the local host in addition to being sent to the loghost, especially if rsyslog has been configured to use the UDP protocol to send messages over a network. UDP does not guarantee reliable delivery, and moderately busy sites will lose log messages occasionally, especially in periods of high traffic which may be the result of an attack. In addition, remote rsyslog messages are not authenticated in any way by default, so it is easy for an attacker to introduce spurious messages to the central log server. Also, some problems cause loss of network connectivity, which will prevent the sending of messages to the central server. For all of these reasons, it is better to store log messages both centrally and on each host, so that they can be correlated if necessary.

Rule Ensure Logs Sent To Remote Host [ref]

To configure rsyslog to send logs to a remote log server, open /etc/rsyslog.conf and read and understand the last section of the file, which describes the multiple directives necessary to activate remote logging. Along with these other directives, the system can be configured to forward its logs to a particular log server by adding or correcting one of the following lines, substituting logcollector appropriately. The choice of protocol depends on the environment of the system; although TCP and RELP provide more reliable message delivery, they may not be supported in all environments.
To use UDP for log message delivery:

*.* @logcollector

To use TCP for log message delivery:

*.* @@logcollector

To use RELP for log message delivery:

*.* :omrelp:logcollector

There must be a resolvable DNS CNAME or Alias record set to "logcollector" for logs to be sent correctly to the centralized logging utility.

Warning: It is important to configure queues in case the client is sending log messages to a remote server. If queues are not configured, the system will stop functioning when the connection to the remote server is not available. Please consult Rsyslog documentation for more information about configuration of queues. The example configuration which should go into /etc/rsyslog.conf can look like the following lines:

$ActionQueueType LinkedList
$ActionQueueFileName queuefilename
$ActionQueueMaxDiskSpace 1g
$ActionQueueSaveOnShutdown on
$ActionResumeRetryCount -1

Rationale:

A log server (loghost) receives syslog messages from one or more systems. This data can be used as an additional log source in the event a system is compromised and its local logs are suspect. Forwarding log messages to a remote loghost also provides system administrators with a centralized place to view the status of multiple hosts within the enterprise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_rsyslog_remote_loghost

References:

cis-csc	1, 13, 14, 15, 16, 2, 3, 5, 6
cobit5	APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.04, DSS05.07, MEA02.01
disa	CCI-000366, CCI-001851
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii)
isa-62443-2009	4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 7.1, SR 7.2
ism	0988, 1405
iso27001-2013	A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.17.2.1
nerc-cip	CIP-003-8 R5.2, CIP-004-6 R3.3
nist	CM-6(a), AU-4(1), AU-9(2)
nist-csf	PR.DS-4, PR.PT-1
os-srg	SRG-OS-000479-GPOS-00224, SRG-OS-000480-GPOS-00227, SRG-OS-000342-GPOS-00133
anssi	R71

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

rsyslog_remote_loghost_address='logcollector'


# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^\*\.\*")

# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "@@$rsyslog_remote_loghost_address"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^\*\.\*\\>" "/etc/rsyslog.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^\*\.\*\\>.*/$escaped_formatted_output/gi" "/etc/rsyslog.conf"
else
    if [[ -s "/etc/rsyslog.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/rsyslog.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/rsyslog.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/rsyslog.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AU-4(1)
  - NIST-800-53-AU-9(2)
  - NIST-800-53-CM-6(a)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - rsyslog_remote_loghost
- name: XCCDF Value rsyslog_remote_loghost_address # promote to variable
  set_fact:
    rsyslog_remote_loghost_address: !!str logcollector
  tags:
    - always

- name: Set rsyslog remote loghost
  lineinfile:
    dest: /etc/rsyslog.conf
    regexp: ^\*\.\*
    line: '*.* @@{{ rsyslog_remote_loghost_address }}'
    create: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AU-4(1)
  - NIST-800-53-AU-9(2)
  - NIST-800-53-CM-6(a)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - rsyslog_remote_loghost

Group Network Configuration and Firewalls Group contains 13 groups and 37 rules

[ref] Most systems must be connected to a network of some sort, and this brings with it the substantial risk of network attack. This section discusses the security impact of decisions about networking which must be made when configuring a system.

This section also discusses firewalls, network access controls, and other network security frameworks, which allow system-level rules to be written that can limit an attackers' ability to connect to your system. These rules can specify that network traffic should be allowed or denied from certain IP addresses, hosts, and networks. The rules can also specify which of the system's network services are available to particular hosts or networks.

Group firewalld Group contains 2 groups and 3 rules

[ref] The dynamic firewall daemon firewalld provides a dynamically managed firewall with support for network “zones” to assign a level of trust to a network and its associated connections and interfaces. It has support for IPv4 and IPv6 firewall settings. It supports Ethernet bridges and has a separation of runtime and permanent configuration options. It also has an interface for services or applications to add firewall rules directly.
A graphical configuration tool, firewall-config, is used to configure firewalld, which in turn uses iptables tool to communicate with Netfilter in the kernel which implements packet filtering.
The firewall service provided by firewalld is dynamic rather than static because changes to the configuration can be made at anytime and are immediately implemented. There is no need to save or apply the changes. No unintended disruption of existing network connections occurs as no part of the firewall has to be reloaded.

Group Inspect and Activate Default firewalld Rules Group contains 1 rule

[ref] Firewalls can be used to separate networks into different zones based on the level of trust the user has decided to place on the devices and traffic within that network. NetworkManager informs firewalld to which zone an interface belongs. An interface's assigned zone can be changed by NetworkManager or via the firewall-config tool.
The zone settings in /etc/firewalld/ are a range of preset settings which can be quickly applied to a network interface. These are the zones provided by firewalld sorted according to the default trust level of the zones from untrusted to trusted:

drop
Any incoming network packets are dropped, there is no reply. Only outgoing network connections are possible.
block
Any incoming network connections are rejected with an icmp-host-prohibited message for IPv4 and icmp6-adm-prohibited for IPv6. Only network connections initiated from within the system are possible.
public
For use in public areas. You do not trust the other computers on the network to not harm your computer. Only selected incoming connections are accepted.
external
For use on external networks with masquerading enabled especially for routers. You do not trust the other computers on the network to not harm your computer. Only selected incoming connections are accepted.
dmz
For computers in your demilitarized zone that are publicly-accessible with limited access to your internal network. Only selected incoming connections are accepted.
work
For use in work areas. You mostly trust the other computers on networks to not harm your computer. Only selected incoming connections are accepted.
home
For use in home areas. You mostly trust the other computers on networks to not harm your computer. Only selected incoming connections are accepted.
internal
For use on internal networks. You mostly trust the other computers on the networks to not harm your computer. Only selected incoming connections are accepted.
trusted
All network connections are accepted.

It is possible to designate one of these zones to be the default zone. When interface connections are added to NetworkManager, they are assigned to the default zone. On installation, the default zone in firewalld is set to be the public zone.
To find out all the settings of a zone, for example the public zone, enter the following command as root:

# firewall-cmd --zone=public --list-all

Example output of this command might look like the following:

# firewall-cmd --zone=public --list-all
public
  interfaces:
  services: mdns dhcpv6-client ssh
  ports:
  forward-ports:
  icmp-blocks: source-quench

To view the network zones currently active, enter the following command as root:

# firewall-cmd --get-service

The following listing displays the result of this command on common Red Hat Virtualization 4 system:

# firewall-cmd --get-service
amanda-client bacula bacula-client dhcp dhcpv6 dhcpv6-client dns ftp
high-availability http https imaps ipp ipp-client ipsec kerberos kpasswd
ldap ldaps libvirt libvirt-tls mdns mountd ms-wbt mysql nfs ntp openvpn
pmcd pmproxy pmwebapi pmwebapis pop3s postgresql proxy-dhcp radius rpc-bind
samba samba-client smtp ssh telnet tftp tftp-client transmission-client
vnc-server wbem-https

Finally to view the network zones that will be active after the next firewalld service reload, enter the following command as root:

# firewall-cmd --get-service --permanent

Rule Verify firewalld Enabled [ref]

The firewalld service can be enabled with the following command:

$ sudo systemctl enable firewalld.service

Rationale:

Access control methods provide the ability to enhance system security posture by restricting services and known good IP addresses and address ranges. This prevents connections from unknown hosts and protocols.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_firewalld_enabled

References:

cis-csc	11, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05
cui	3.1.3, 3.4.7
disa	CCI-000382, CCI-000366, CCI-002314
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4
nerc-cip	CIP-003-8 R4, CIP-003-8 R5, CIP-004-6 R3
nist	AC-4, CM-7(b), CA-3(5), SC-7(21), CM-6(a)
nist-csf	PR.IP-1
ospp	FMT_SMF_EXT.1
os-srg	SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232
bsi	SYS.1.6.A5, SYS.1.6.A21
pcidss4	1.2.1, 1.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && { rpm --quiet -q firewalld; }; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'firewalld.service'
"$SYSTEMCTL_EXEC" start 'firewalld.service'
"$SYSTEMCTL_EXEC" enable 'firewalld.service'

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
enabled = ["firewalld"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.3
  - NIST-800-171-3.4.7
  - NIST-800-53-AC-4
  - NIST-800-53-CA-3(5)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(21)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_firewalld_enabled

- name: Verify firewalld Enabled - Enable service firewalld
  block:

  - name: Gather the package facts
    package_facts:
      manager: auto

  - name: Verify firewalld Enabled - Enable Service firewalld
    ansible.builtin.systemd:
      name: firewalld
      enabled: true
      state: started
      masked: false
    when:
    - '"firewalld" in ansible_facts.packages'
  when:
  - '"kernel" in ansible_facts.packages'
  - '"firewalld" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.3
  - NIST-800-171-3.4.7
  - NIST-800-53-AC-4
  - NIST-800-53-CA-3(5)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(21)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_firewalld_enabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include enable_firewalld

class enable_firewalld {
  service {'firewalld':
    enable => true,
    ensure => 'running',
  }
}

Group Strengthen the Default Ruleset Group contains 2 rules

[ref] The default rules can be strengthened. The system scripts that activate the firewall rules expect them to be defined in configuration files under the /etc/firewalld/services and /etc/firewalld/zones directories.

The following recommendations describe how to strengthen the default ruleset configuration file. An alternative to editing this configuration file is to create a shell script that makes calls to the firewall-cmd program to load in rules under the /etc/firewalld/services and /etc/firewalld/zones directories.

Instructions apply to both unless otherwise noted. Language and address conventions for regular firewalld rules are used throughout this section.

Warning: The program firewall-config allows additional services to penetrate the default firewall rules and automatically adjusts the firewalld ruleset(s).

Rule Configure the Firewalld Ports [ref]

Configure the firewalld ports to allow approved services to have access to the system. To configure firewalld to open ports, run the following command:

firewall-cmd --permanent --add-port=port_number/tcp

To configure firewalld to allow access for pre-defined services, run the following command:

firewall-cmd --permanent --add-service=service_name

Rationale:

In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems.

Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by one component.

To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_configure_firewalld_ports

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
disa	CCI-000382, CCI-002314
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
ism	1416
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	AC-4, CM-7(b), CA-3(5), SC-7(21), CM-6(a)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115
pcidss4	1.3.1, 1.3

Rule Set Default firewalld Zone for Incoming Packets [ref]

To set the default zone to drop for the built-in default zone which processes incoming IPv4 and IPv6 packets, modify the following line in /etc/firewalld/firewalld.conf to be:

DefaultZone=drop

Warning: To prevent denying any access to the system, automatic remediation of this control is not available. Remediation must be automated as a component of machine provisioning, or followed manually as outlined above.

Rationale:

In firewalld the default zone is applied only after all the applicable rules in the table are examined for a match. Setting the default zone to drop implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_set_firewalld_default_zone

References:

cis-csc	11, 14, 3, 9
cjis	5.10.1
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.1.3, 3.4.7, 3.13.6
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
ism	1416
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CA-3(5), CM-7(b), SC-7(23), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3
pcidss	Req-1.4
os-srg	SRG-OS-000480-GPOS-00227
pcidss4	1.3.1, 1.3

Group IPSec Support Group contains 1 rule

[ref] Support for Internet Protocol Security (IPsec) is provided with Libreswan.

Rule Verify Any Configured IPSec Tunnel Connections [ref]

Libreswan provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. As such, IPsec can be used to circumvent certain network requirements such as filtering. Verify that if any IPsec connection (conn) configured in /etc/ipsec.conf and /etc/ipsec.d exists is an approved organizational connection.

Warning: Automatic remediation of this control is not available due to the unique requirements of each system.

Rationale:

IP tunneling mechanisms can be used to bypass network filtering.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_libreswan_approved_tunnels

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9
cobit5	APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02
disa	CCI-000366
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.4.3.3
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	AC-17(a), MA-4(6), CM-6(a), AC-4, SC-8
nist-csf	DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227

Group IPv6 Group contains 2 groups and 10 rules

[ref] The system includes support for Internet Protocol version 6. A major and often-mentioned improvement over IPv4 is its enormous increase in the number of available addresses. Another important feature is its support for automatic configuration of many network settings.

Group Disable Support for IPv6 Unless Needed Group contains 2 rules

[ref] Despite configuration that suggests support for IPv6 has been disabled, link-local IPv6 address auto-configuration occurs even when only an IPv4 address is assigned. The only way to effectively prevent execution of the IPv6 networking stack is to instruct the system not to activate the IPv6 kernel module.

Rule Disable Support for RPC IPv6 [ref]

RPC services for NFSv4 try to load transport modules for udp6 and tcp6 by default, even if IPv6 has been disabled in /etc/modprobe.d. To prevent RPC services such as rpc.mountd from attempting to start IPv6 network listeners, remove or comment out the following two lines in /etc/netconfig:

udp6       tpi_clts      v     inet6    udp     -       -
tcp6       tpi_cots_ord  v     inet6    tcp     -       -

Rationale:

Severity:

unknown

Rule ID: xccdf_org.ssgproject.content_rule_network_ipv6_disable_rpc

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.1.20
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3

Remediation Shell script ⇲


# Drop 'tcp6' and 'udp6' entries from /etc/netconfig to prevent RPC
# services for NFSv4 from attempting to start IPv6 network listeners
declare -a IPV6_RPC_ENTRIES=("tcp6" "udp6")

for rpc_entry in "${IPV6_RPC_ENTRIES[@]}"
do
	sed -i "/^${rpc_entry}[[:space:]]\\+tpi\\_.*inet6.*/d" /etc/netconfig
done

Rule Disable IPv6 Addressing on All IPv6 Interfaces [ref]

To disable support for (ipv6) addressing on all interface add the following line to /etc/sysctl.d/ipv6.conf (or another file in /etc/sysctl.d):

net.ipv6.conf.all.disable_ipv6 = 1

This disables IPv6 on all network interfaces as other services and system functionality require the IPv6 stack loaded to work.

Rationale:

Any unnecessary network stacks - including IPv6 - should be disabled, to reduce the vulnerability to exploitation.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_disable_ipv6

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.1.20
disa	CCI-001551
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv6.conf.all.disable_ipv6 from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.disable_ipv6.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv6.conf.all.disable_ipv6" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"


#
# Set runtime for net.ipv6.conf.all.disable_ipv6
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv6.conf.all.disable_ipv6="1"
fi

#
# If net.ipv6.conf.all.disable_ipv6 present in /etc/sysctl.conf, change value to "1"
#	else, add "net.ipv6.conf.all.disable_ipv6 = 1" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.disable_ipv6")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.disable_ipv6\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.disable_ipv6\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_disable_ipv6

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv6.conf.all.disable_ipv6.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_disable_ipv6

- name: Comment out any occurrences of net.ipv6.conf.all.disable_ipv6 from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv6.conf.all.disable_ipv6
    replace: '#net.ipv6.conf.all.disable_ipv6'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_disable_ipv6

- name: Ensure sysctl net.ipv6.conf.all.disable_ipv6 is set to 1
  sysctl:
    name: net.ipv6.conf.all.disable_ipv6
    value: '1'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_disable_ipv6

Group Configure IPv6 Settings if Necessary Group contains 8 rules

[ref] A major feature of IPv6 is the extent to which systems implementing it can automatically configure their networking devices using information from the network. From a security perspective, manually configuring important configuration information is preferable to accepting it from the network in an unauthenticated fashion.

Rule Use Privacy Extensions for Address [ref]

To introduce randomness into the automatic generation of IPv6 addresses, add or correct the following line in

/etc/sysconfig/network-scripts/ifcfg-interface

IPV6_PRIVACY=rfc3041

Automatically-generated IPv6 addresses are based on the underlying hardware (e.g. Ethernet) address, and so it becomes possible to track a piece of hardware over its lifetime using its traffic. If it is important for a system's IP address to not trivially reveal its hardware address, this setting should be applied.

Rationale:

Severity:

unknown

Rule ID: xccdf_org.ssgproject.content_rule_network_ipv6_privacy_extensions

References:

cui	3.1.20
disa	CCI-000366

Remediation Shell script ⇲


# enable randomness in ipv6 address generation
for interface in /etc/sysconfig/network-scripts/ifcfg-*
do
    echo "IPV6_PRIVACY=rfc3041" >> $interface
done

Rule Configure Accepting Router Advertisements on All IPv6 Interfaces [ref]

To set the runtime status of the net.ipv6.conf.all.accept_ra kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.all.accept_ra=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv6.conf.all.accept_ra = 0

Rationale:

An illicit router advertisement message could result in a man-in-the-middle attack.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_accept_ra

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv6.conf.all.accept_ra from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_ra.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv6.conf.all.accept_ra" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv6_conf_all_accept_ra_value='0'


#
# Set runtime for net.ipv6.conf.all.accept_ra
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv6.conf.all.accept_ra="$sysctl_net_ipv6_conf_all_accept_ra_value"
fi

#
# If net.ipv6.conf.all.accept_ra present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv6.conf.all.accept_ra = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_ra")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_ra_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.accept_ra\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_ra\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_ra

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv6.conf.all.accept_ra.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_ra

- name: Comment out any occurrences of net.ipv6.conf.all.accept_ra from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv6.conf.all.accept_ra
    replace: '#net.ipv6.conf.all.accept_ra'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_ra
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_ra_value # promote to variable
  set_fact:
    sysctl_net_ipv6_conf_all_accept_ra_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv6.conf.all.accept_ra is set
  sysctl:
    name: net.ipv6.conf.all.accept_ra
    value: '{{ sysctl_net_ipv6_conf_all_accept_ra_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_ra

Rule Disable Accepting ICMP Redirects for All IPv6 Interfaces [ref]

To set the runtime status of the net.ipv6.conf.all.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.all.accept_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv6.conf.all.accept_redirects = 0

Rationale:

An illicit ICMP redirect message could result in a man-in-the-middle attack.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_accept_redirects

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv)
nist-csf	PR.IP-1, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R13

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv6.conf.all.accept_redirects from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_redirects.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv6.conf.all.accept_redirects" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv6_conf_all_accept_redirects_value='0'


#
# Set runtime for net.ipv6.conf.all.accept_redirects
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv6.conf.all.accept_redirects="$sysctl_net_ipv6_conf_all_accept_redirects_value"
fi

#
# If net.ipv6.conf.all.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv6.conf.all.accept_redirects = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_redirects")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_redirects_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_redirects

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv6.conf.all.accept_redirects.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_redirects

- name: Comment out any occurrences of net.ipv6.conf.all.accept_redirects from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv6.conf.all.accept_redirects
    replace: '#net.ipv6.conf.all.accept_redirects'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_redirects
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_redirects_value # promote to variable
  set_fact:
    sysctl_net_ipv6_conf_all_accept_redirects_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv6.conf.all.accept_redirects is set
  sysctl:
    name: net.ipv6.conf.all.accept_redirects
    value: '{{ sysctl_net_ipv6_conf_all_accept_redirects_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_redirects

Rule Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces [ref]

To set the runtime status of the net.ipv6.conf.all.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.all.accept_source_route=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv6.conf.all.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router.

Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_accept_source_route

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9
cobit5	APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.4.3.3
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R13

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv6.conf.all.accept_source_route from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_source_route.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv6.conf.all.accept_source_route" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv6_conf_all_accept_source_route_value='0'


#
# Set runtime for net.ipv6.conf.all.accept_source_route
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv6.conf.all.accept_source_route="$sysctl_net_ipv6_conf_all_accept_source_route_value"
fi

#
# If net.ipv6.conf.all.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv6.conf.all.accept_source_route = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_source_route")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_source_route_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_source_route

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv6.conf.all.accept_source_route.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_source_route

- name: Comment out any occurrences of net.ipv6.conf.all.accept_source_route from
    config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv6.conf.all.accept_source_route
    replace: '#net.ipv6.conf.all.accept_source_route'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_source_route
- name: XCCDF Value sysctl_net_ipv6_conf_all_accept_source_route_value # promote to variable
  set_fact:
    sysctl_net_ipv6_conf_all_accept_source_route_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv6.conf.all.accept_source_route is set
  sysctl:
    name: net.ipv6.conf.all.accept_source_route
    value: '{{ sysctl_net_ipv6_conf_all_accept_source_route_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_accept_source_route

Rule Disable Kernel Parameter for IPv6 Forwarding [ref]

To set the runtime status of the net.ipv6.conf.all.forwarding kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.all.forwarding=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv6.conf.all.forwarding = 0

Rationale:

IP forwarding permits the kernel to forward packets from one network interface to another. The ability to forward packets between two networks is only appropriate for systems acting as routers.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_forwarding

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9
cobit5	APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv)
nist-csf	DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv6.conf.all.forwarding from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.forwarding.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv6.conf.all.forwarding" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv6_conf_all_forwarding_value='0'


#
# Set runtime for net.ipv6.conf.all.forwarding
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv6.conf.all.forwarding="$sysctl_net_ipv6_conf_all_forwarding_value"
fi

#
# If net.ipv6.conf.all.forwarding present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv6.conf.all.forwarding = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.forwarding")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_forwarding_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.forwarding\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.forwarding\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_forwarding

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv6.conf.all.forwarding.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_forwarding

- name: Comment out any occurrences of net.ipv6.conf.all.forwarding from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv6.conf.all.forwarding
    replace: '#net.ipv6.conf.all.forwarding'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_forwarding
- name: XCCDF Value sysctl_net_ipv6_conf_all_forwarding_value # promote to variable
  set_fact:
    sysctl_net_ipv6_conf_all_forwarding_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv6.conf.all.forwarding is set
  sysctl:
    name: net.ipv6.conf.all.forwarding
    value: '{{ sysctl_net_ipv6_conf_all_forwarding_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_all_forwarding

Rule Disable Accepting Router Advertisements on all IPv6 Interfaces by Default [ref]

To set the runtime status of the net.ipv6.conf.default.accept_ra kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.default.accept_ra=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv6.conf.default.accept_ra = 0

Rationale:

An illicit router advertisement message could result in a man-in-the-middle attack.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_ra

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv6.conf.default.accept_ra from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_ra.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv6.conf.default.accept_ra" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv6_conf_default_accept_ra_value='0'


#
# Set runtime for net.ipv6.conf.default.accept_ra
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv6.conf.default.accept_ra="$sysctl_net_ipv6_conf_default_accept_ra_value"
fi

#
# If net.ipv6.conf.default.accept_ra present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv6.conf.default.accept_ra = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_ra")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_ra_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_ra\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_ra\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_ra

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv6.conf.default.accept_ra.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_ra

- name: Comment out any occurrences of net.ipv6.conf.default.accept_ra from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv6.conf.default.accept_ra
    replace: '#net.ipv6.conf.default.accept_ra'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_ra
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_ra_value # promote to variable
  set_fact:
    sysctl_net_ipv6_conf_default_accept_ra_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv6.conf.default.accept_ra is set
  sysctl:
    name: net.ipv6.conf.default.accept_ra
    value: '{{ sysctl_net_ipv6_conf_default_accept_ra_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_ra

Rule Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv6 Interfaces [ref]

To set the runtime status of the net.ipv6.conf.default.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv6.conf.default.accept_redirects = 0

Rationale:

An illicit ICMP redirect message could result in a man-in-the-middle attack.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_redirects

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R13

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv6.conf.default.accept_redirects from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_redirects.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv6.conf.default.accept_redirects" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv6_conf_default_accept_redirects_value='0'


#
# Set runtime for net.ipv6.conf.default.accept_redirects
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv6.conf.default.accept_redirects="$sysctl_net_ipv6_conf_default_accept_redirects_value"
fi

#
# If net.ipv6.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv6.conf.default.accept_redirects = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_redirects")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_redirects_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_redirects

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv6.conf.default.accept_redirects.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_redirects

- name: Comment out any occurrences of net.ipv6.conf.default.accept_redirects from
    config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv6.conf.default.accept_redirects
    replace: '#net.ipv6.conf.default.accept_redirects'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_redirects
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_redirects_value # promote to variable
  set_fact:
    sysctl_net_ipv6_conf_default_accept_redirects_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv6.conf.default.accept_redirects is set
  sysctl:
    name: net.ipv6.conf.default.accept_redirects
    value: '{{ sysctl_net_ipv6_conf_default_accept_redirects_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_redirects

Rule Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default [ref]

To set the runtime status of the net.ipv6.conf.default.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv6.conf.default.accept_source_route=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv6.conf.default.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router. Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_source_route

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9
cobit5	APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.4.3.3
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv)
nist-csf	DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4
pcidss	Req-1.4.3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R13
pcidss4	1.4.2, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv6.conf.default.accept_source_route from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_source_route.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv6.conf.default.accept_source_route" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv6_conf_default_accept_source_route_value='0'


#
# Set runtime for net.ipv6.conf.default.accept_source_route
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv6.conf.default.accept_source_route="$sysctl_net_ipv6_conf_default_accept_source_route_value"
fi

#
# If net.ipv6.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv6.conf.default.accept_source_route = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_source_route")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_source_route_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_source_route

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv6.conf.default.accept_source_route.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_source_route

- name: Comment out any occurrences of net.ipv6.conf.default.accept_source_route from
    config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv6.conf.default.accept_source_route
    replace: '#net.ipv6.conf.default.accept_source_route'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_source_route
- name: XCCDF Value sysctl_net_ipv6_conf_default_accept_source_route_value # promote to variable
  set_fact:
    sysctl_net_ipv6_conf_default_accept_source_route_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv6.conf.default.accept_source_route is set
  sysctl:
    name: net.ipv6.conf.default.accept_source_route
    value: '{{ sysctl_net_ipv6_conf_default_accept_source_route_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv6_conf_default_accept_source_route

Group Kernel Parameters Which Affect Networking Group contains 2 groups and 16 rules

[ref] The sysctl utility is used to set parameters which affect the operation of the Linux kernel. Kernel parameters which affect networking and have security implications are described here.

Group Network Related Kernel Runtime Parameters for Hosts and Routers Group contains 13 rules

[ref] Certain kernel parameters should be set for systems which are acting as either hosts or routers to improve the system's ability defend against certain types of IPv4 protocol attacks.

Rule Disable Accepting ICMP Redirects for All IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.conf.all.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.all.accept_redirects = 0

Rationale:

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.
This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required."

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_accept_redirects

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9
cjis	5.10.1.1
cobit5	APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a), SC-7(a)
nist-csf	DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.all.accept_redirects from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.accept_redirects.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.all.accept_redirects" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_all_accept_redirects_value='0'


#
# Set runtime for net.ipv4.conf.all.accept_redirects
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.all.accept_redirects="$sysctl_net_ipv4_conf_all_accept_redirects_value"
fi

#
# If net.ipv4.conf.all.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.accept_redirects = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.accept_redirects")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_accept_redirects_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_accept_redirects

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.all.accept_redirects.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_accept_redirects

- name: Comment out any occurrences of net.ipv4.conf.all.accept_redirects from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.all.accept_redirects
    replace: '#net.ipv4.conf.all.accept_redirects'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_accept_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_all_accept_redirects_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_all_accept_redirects_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.all.accept_redirects is set
  sysctl:
    name: net.ipv4.conf.all.accept_redirects
    value: '{{ sysctl_net_ipv4_conf_all_accept_redirects_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_accept_redirects

Rule Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.conf.all.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.all.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router.

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_accept_source_route

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9
cobit5	APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1
nist	CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.all.accept_source_route from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.accept_source_route.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.all.accept_source_route" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_all_accept_source_route_value='0'


#
# Set runtime for net.ipv4.conf.all.accept_source_route
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.all.accept_source_route="$sysctl_net_ipv4_conf_all_accept_source_route_value"
fi

#
# If net.ipv4.conf.all.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.accept_source_route = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.accept_source_route")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_accept_source_route_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_accept_source_route

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.all.accept_source_route.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_accept_source_route

- name: Comment out any occurrences of net.ipv4.conf.all.accept_source_route from
    config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.all.accept_source_route
    replace: '#net.ipv4.conf.all.accept_source_route'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_accept_source_route
- name: XCCDF Value sysctl_net_ipv4_conf_all_accept_source_route_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_all_accept_source_route_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.all.accept_source_route is set
  sysctl:
    name: net.ipv4.conf.all.accept_source_route
    value: '{{ sysctl_net_ipv4_conf_all_accept_source_route_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_accept_source_route

Rule Enable Kernel Parameter to Log Martian Packets on all IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.conf.all.log_martians kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.log_martians=1

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.all.log_martians = 1

Rationale:

The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.

Severity:

unknown

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_log_martians

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9
cobit5	APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.04, DSS03.05, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), SC-5(3)(a)
nist-csf	DE.CM-1, PR.AC-3, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.all.log_martians from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.log_martians.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.all.log_martians" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_all_log_martians_value='1'


#
# Set runtime for net.ipv4.conf.all.log_martians
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.all.log_martians="$sysctl_net_ipv4_conf_all_log_martians_value"
fi

#
# If net.ipv4.conf.all.log_martians present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.log_martians = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.log_martians")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_log_martians_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.log_martians\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.log_martians\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(3)(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_conf_all_log_martians
  - unknown_severity

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.all.log_martians.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(3)(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_conf_all_log_martians
  - unknown_severity

- name: Comment out any occurrences of net.ipv4.conf.all.log_martians from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.all.log_martians
    replace: '#net.ipv4.conf.all.log_martians'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(3)(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_conf_all_log_martians
  - unknown_severity
- name: XCCDF Value sysctl_net_ipv4_conf_all_log_martians_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_all_log_martians_value: !!str 1
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.all.log_martians is set
  sysctl:
    name: net.ipv4.conf.all.log_martians
    value: '{{ sysctl_net_ipv4_conf_all_log_martians_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(3)(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_conf_all_log_martians
  - unknown_severity

Rule Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.conf.all.rp_filter kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.rp_filter=1

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.all.rp_filter = 1

Rationale:

Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_rp_filter

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9
cobit5	APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.4.3.3
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), CM-6(a), SC-7(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4
pcidss	Req-1.4.3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12
pcidss4	1.4.3, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.all.rp_filter from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.rp_filter.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.all.rp_filter" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_all_rp_filter_value='1'


#
# Set runtime for net.ipv4.conf.all.rp_filter
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.all.rp_filter="$sysctl_net_ipv4_conf_all_rp_filter_value"
fi

#
# If net.ipv4.conf.all.rp_filter present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.rp_filter = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.rp_filter")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_rp_filter_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.rp_filter\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.rp_filter\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_rp_filter

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.all.rp_filter.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_rp_filter

- name: Comment out any occurrences of net.ipv4.conf.all.rp_filter from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.all.rp_filter
    replace: '#net.ipv4.conf.all.rp_filter'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_rp_filter
- name: XCCDF Value sysctl_net_ipv4_conf_all_rp_filter_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_all_rp_filter_value: !!str 1
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.all.rp_filter is set
  sysctl:
    name: net.ipv4.conf.all.rp_filter
    value: '{{ sysctl_net_ipv4_conf_all_rp_filter_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_rp_filter

Rule Disable Kernel Parameter for Accepting Secure ICMP Redirects on all IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.conf.all.secure_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.all.secure_redirects = 0

Rationale:

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_secure_redirects

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9
cobit5	APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06
cui	3.1.20
disa	CCI-001503, CCI-001551
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), CM-6(a), SC-7(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4
pcidss	Req-1.4.3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12
pcidss4	1.4.3, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.all.secure_redirects from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.secure_redirects.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.all.secure_redirects" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_all_secure_redirects_value='0'


#
# Set runtime for net.ipv4.conf.all.secure_redirects
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.all.secure_redirects="$sysctl_net_ipv4_conf_all_secure_redirects_value"
fi

#
# If net.ipv4.conf.all.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.all.secure_redirects = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.secure_redirects")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_secure_redirects_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.secure_redirects\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.secure_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_secure_redirects

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.all.secure_redirects.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_secure_redirects

- name: Comment out any occurrences of net.ipv4.conf.all.secure_redirects from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.all.secure_redirects
    replace: '#net.ipv4.conf.all.secure_redirects'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_secure_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_all_secure_redirects_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_all_secure_redirects_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.all.secure_redirects is set
  sysctl:
    name: net.ipv4.conf.all.secure_redirects
    value: '{{ sysctl_net_ipv4_conf_all_secure_redirects_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_secure_redirects

Rule Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.conf.default.accept_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.default.accept_redirects = 0

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_accept_redirects

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9
cjis	5.10.1.1
cobit5	APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), CM-6(a), SC-7(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4
pcidss	Req-1.4.3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12
pcidss4	1.4.3, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.default.accept_redirects from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.accept_redirects.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.default.accept_redirects" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_default_accept_redirects_value='0'


#
# Set runtime for net.ipv4.conf.default.accept_redirects
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.default.accept_redirects="$sysctl_net_ipv4_conf_default_accept_redirects_value"
fi

#
# If net.ipv4.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.default.accept_redirects = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.accept_redirects")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_accept_redirects_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_accept_redirects

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.default.accept_redirects.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_accept_redirects

- name: Comment out any occurrences of net.ipv4.conf.default.accept_redirects from
    config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.default.accept_redirects
    replace: '#net.ipv4.conf.default.accept_redirects'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_accept_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_default_accept_redirects_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_default_accept_redirects_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.default.accept_redirects is set
  sysctl:
    name: net.ipv4.conf.default.accept_redirects
    value: '{{ sysctl_net_ipv4_conf_default_accept_redirects_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_accept_redirects

Rule Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default [ref]

To set the runtime status of the net.ipv4.conf.default.accept_source_route kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.default.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures.
Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required, such as when IPv4 forwarding is enabled and the system is legitimately functioning as a router.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_accept_source_route

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9
cjis	5.10.1.1
cobit5	APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1
nist	CM-7(a), CM-7(b), SC-5, SC-7(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.default.accept_source_route from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.accept_source_route.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.default.accept_source_route" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_default_accept_source_route_value='0'


#
# Set runtime for net.ipv4.conf.default.accept_source_route
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.default.accept_source_route="$sysctl_net_ipv4_conf_default_accept_source_route_value"
fi

#
# If net.ipv4.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.default.accept_source_route = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.accept_source_route")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_accept_source_route_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_accept_source_route

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.default.accept_source_route.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_accept_source_route

- name: Comment out any occurrences of net.ipv4.conf.default.accept_source_route from
    config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.default.accept_source_route
    replace: '#net.ipv4.conf.default.accept_source_route'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_accept_source_route
- name: XCCDF Value sysctl_net_ipv4_conf_default_accept_source_route_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_default_accept_source_route_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.default.accept_source_route is set
  sysctl:
    name: net.ipv4.conf.default.accept_source_route
    value: '{{ sysctl_net_ipv4_conf_default_accept_source_route_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_accept_source_route

Rule Enable Kernel Paremeter to Log Martian Packets on all IPv4 Interfaces by Default [ref]

To set the runtime status of the net.ipv4.conf.default.log_martians kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.log_martians=1

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.default.log_martians = 1

Rationale:

Severity:

unknown

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_log_martians

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9
cobit5	APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.04, DSS03.05, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), SC-5(3)(a)
nist-csf	DE.CM-1, PR.AC-3, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.default.log_martians from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.log_martians.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.default.log_martians" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_default_log_martians_value='1'


#
# Set runtime for net.ipv4.conf.default.log_martians
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.default.log_martians="$sysctl_net_ipv4_conf_default_log_martians_value"
fi

#
# If net.ipv4.conf.default.log_martians present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.default.log_martians = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.log_martians")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_log_martians_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.log_martians\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.log_martians\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(3)(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_conf_default_log_martians
  - unknown_severity

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.default.log_martians.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(3)(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_conf_default_log_martians
  - unknown_severity

- name: Comment out any occurrences of net.ipv4.conf.default.log_martians from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.default.log_martians
    replace: '#net.ipv4.conf.default.log_martians'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(3)(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_conf_default_log_martians
  - unknown_severity
- name: XCCDF Value sysctl_net_ipv4_conf_default_log_martians_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_default_log_martians_value: !!str 1
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.default.log_martians is set
  sysctl:
    name: net.ipv4.conf.default.log_martians
    value: '{{ sysctl_net_ipv4_conf_default_log_martians_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(3)(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_conf_default_log_martians
  - unknown_severity

Rule Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces by Default [ref]

To set the runtime status of the net.ipv4.conf.default.rp_filter kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.rp_filter=1

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.default.rp_filter = 1

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_rp_filter

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9
cobit5	APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.4.3.3
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), CM-6(a), SC-7(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.default.rp_filter from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.rp_filter.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.default.rp_filter" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_default_rp_filter_value='1'


#
# Set runtime for net.ipv4.conf.default.rp_filter
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.default.rp_filter="$sysctl_net_ipv4_conf_default_rp_filter_value"
fi

#
# If net.ipv4.conf.default.rp_filter present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.default.rp_filter = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.rp_filter")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_rp_filter_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.rp_filter\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.rp_filter\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_rp_filter

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.default.rp_filter.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_rp_filter

- name: Comment out any occurrences of net.ipv4.conf.default.rp_filter from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.default.rp_filter
    replace: '#net.ipv4.conf.default.rp_filter'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_rp_filter
- name: XCCDF Value sysctl_net_ipv4_conf_default_rp_filter_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_default_rp_filter_value: !!str 1
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.default.rp_filter is set
  sysctl:
    name: net.ipv4.conf.default.rp_filter
    value: '{{ sysctl_net_ipv4_conf_default_rp_filter_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_rp_filter

Rule Configure Kernel Parameter for Accepting Secure Redirects By Default [ref]

To set the runtime status of the net.ipv4.conf.default.secure_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.default.secure_redirects = 0

Rationale:

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_secure_redirects

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9
cobit5	APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06
cui	3.1.20
disa	CCI-001551
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1
nist	CM-7(a), CM-7(b), SC-5, SC-7(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.default.secure_redirects from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.secure_redirects.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.default.secure_redirects" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_conf_default_secure_redirects_value='0'


#
# Set runtime for net.ipv4.conf.default.secure_redirects
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.default.secure_redirects="$sysctl_net_ipv4_conf_default_secure_redirects_value"
fi

#
# If net.ipv4.conf.default.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.conf.default.secure_redirects = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.secure_redirects")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_secure_redirects_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.secure_redirects\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.secure_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_secure_redirects

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.default.secure_redirects.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_secure_redirects

- name: Comment out any occurrences of net.ipv4.conf.default.secure_redirects from
    config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.default.secure_redirects
    replace: '#net.ipv4.conf.default.secure_redirects'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_secure_redirects
- name: XCCDF Value sysctl_net_ipv4_conf_default_secure_redirects_value # promote to variable
  set_fact:
    sysctl_net_ipv4_conf_default_secure_redirects_value: !!str 0
  tags:
    - always

- name: Ensure sysctl net.ipv4.conf.default.secure_redirects is set
  sysctl:
    name: net.ipv4.conf.default.secure_redirects
    value: '{{ sysctl_net_ipv4_conf_default_secure_redirects_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_secure_redirects

Rule Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requests on IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.icmp_echo_ignore_broadcasts kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.icmp_echo_ignore_broadcasts = 1

Rationale:

Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks.
Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_icmp_echo_ignore_broadcasts

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9
cjis	5.10.1.1
cobit5	APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1
nist	CM-7(a), CM-7(b), SC-5
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4
pcidss	Req-1.4.3
os-srg	SRG-OS-000480-GPOS-00227
pcidss4	1.4.2, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.icmp_echo_ignore_broadcasts from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.icmp_echo_ignore_broadcasts.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.icmp_echo_ignore_broadcasts" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value='1'


#
# Set runtime for net.ipv4.icmp_echo_ignore_broadcasts
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.icmp_echo_ignore_broadcasts="$sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value"
fi

#
# If net.ipv4.icmp_echo_ignore_broadcasts present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.icmp_echo_ignore_broadcasts = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.icmp_echo_ignore_broadcasts")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.icmp_echo_ignore_broadcasts\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.icmp_echo_ignore_broadcasts\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_icmp_echo_ignore_broadcasts

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.icmp_echo_ignore_broadcasts.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_icmp_echo_ignore_broadcasts

- name: Comment out any occurrences of net.ipv4.icmp_echo_ignore_broadcasts from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.icmp_echo_ignore_broadcasts
    replace: '#net.ipv4.icmp_echo_ignore_broadcasts'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_icmp_echo_ignore_broadcasts
- name: XCCDF Value sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value # promote to variable
  set_fact:
    sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value: !!str 1
  tags:
    - always

- name: Ensure sysctl net.ipv4.icmp_echo_ignore_broadcasts is set
  sysctl:
    name: net.ipv4.icmp_echo_ignore_broadcasts
    value: '{{ sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_icmp_echo_ignore_broadcasts

Rule Enable Kernel Parameter to Ignore Bogus ICMP Error Responses on IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.icmp_ignore_bogus_error_responses kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.icmp_ignore_bogus_error_responses = 1

Rationale:

Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged.

Severity:

unknown

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_icmp_ignore_bogus_error_responses

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9
cobit5	APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2
nerc-cip	CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1
nist	CM-7(a), CM-7(b), SC-5
nist-csf	DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3
pcidss	Req-1.4.3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12
pcidss4	1.4.2, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.icmp_ignore_bogus_error_responses" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value='1'


#
# Set runtime for net.ipv4.icmp_ignore_bogus_error_responses
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.icmp_ignore_bogus_error_responses="$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value"
fi

#
# If net.ipv4.icmp_ignore_bogus_error_responses present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.icmp_ignore_bogus_error_responses = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.icmp_ignore_bogus_error_responses")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.icmp_ignore_bogus_error_responses\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.icmp_ignore_bogus_error_responses\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_icmp_ignore_bogus_error_responses
  - unknown_severity

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_icmp_ignore_bogus_error_responses
  - unknown_severity

- name: Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses
    from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses
    replace: '#net.ipv4.icmp_ignore_bogus_error_responses'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_icmp_ignore_bogus_error_responses
  - unknown_severity
- name: XCCDF Value sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value # promote to variable
  set_fact:
    sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value: !!str 1
  tags:
    - always

- name: Ensure sysctl net.ipv4.icmp_ignore_bogus_error_responses is set
  sysctl:
    name: net.ipv4.icmp_ignore_bogus_error_responses
    value: '{{ sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - PCI-DSS-Req-1.4.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - low_complexity
  - medium_disruption
  - reboot_required
  - sysctl_net_ipv4_icmp_ignore_bogus_error_responses
  - unknown_severity

Rule Enable Kernel Parameter to Use TCP Syncookies on Network Interfaces [ref]

To set the runtime status of the net.ipv4.tcp_syncookies kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.tcp_syncookies=1

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.tcp_syncookies = 1

Rationale:

A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected, and enables the system to continue servicing valid connection requests.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_tcp_syncookies

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9
cjis	5.10.1.1
cobit5	APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02
cui	3.1.20
disa	CCI-001095, CCI-000366, CCI-002385
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.4.3.3
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), SC-5(1), SC-5(2), SC-5(3)(a), CM-6(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4
pcidss	Req-1.4.1
os-srg	SRG-OS-000480-GPOS-00227, SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00071
anssi	R12
pcidss4	1.4.3, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.tcp_syncookies from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.tcp_syncookies.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.tcp_syncookies" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"

sysctl_net_ipv4_tcp_syncookies_value='1'


#
# Set runtime for net.ipv4.tcp_syncookies
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.tcp_syncookies="$sysctl_net_ipv4_tcp_syncookies_value"
fi

#
# If net.ipv4.tcp_syncookies present in /etc/sysctl.conf, change value to appropriate value
#	else, add "net.ipv4.tcp_syncookies = value" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.tcp_syncookies")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_tcp_syncookies_value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.tcp_syncookies\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.tcp_syncookies\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(1)
  - NIST-800-53-SC-5(2)
  - NIST-800-53-SC-5(3)(a)
  - PCI-DSS-Req-1.4.1
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_tcp_syncookies

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.tcp_syncookies.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(1)
  - NIST-800-53-SC-5(2)
  - NIST-800-53-SC-5(3)(a)
  - PCI-DSS-Req-1.4.1
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_tcp_syncookies

- name: Comment out any occurrences of net.ipv4.tcp_syncookies from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.tcp_syncookies
    replace: '#net.ipv4.tcp_syncookies'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(1)
  - NIST-800-53-SC-5(2)
  - NIST-800-53-SC-5(3)(a)
  - PCI-DSS-Req-1.4.1
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_tcp_syncookies
- name: XCCDF Value sysctl_net_ipv4_tcp_syncookies_value # promote to variable
  set_fact:
    sysctl_net_ipv4_tcp_syncookies_value: !!str 1
  tags:
    - always

- name: Ensure sysctl net.ipv4.tcp_syncookies is set
  sysctl:
    name: net.ipv4.tcp_syncookies
    value: '{{ sysctl_net_ipv4_tcp_syncookies_value }}'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5(1)
  - NIST-800-53-SC-5(2)
  - NIST-800-53-SC-5(3)(a)
  - PCI-DSS-Req-1.4.1
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_tcp_syncookies

Group Network Parameters for Hosts Only Group contains 3 rules

[ref] If the system is not going to be used as a router, then setting certain kernel parameters ensure that the host will not perform routing of network traffic.

Rule Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.conf.all.send_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.all.send_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.all.send_redirects = 0

Rationale:

ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology.
The ability to send ICMP redirects is only appropriate for systems acting as routers.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_send_redirects

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9
cjis	5.10.1.1
cobit5	APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1
nist	CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12
pcidss4	1.4.5, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.all.send_redirects from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.send_redirects.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.all.send_redirects" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"


#
# Set runtime for net.ipv4.conf.all.send_redirects
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.all.send_redirects="0"
fi

#
# If net.ipv4.conf.all.send_redirects present in /etc/sysctl.conf, change value to "0"
#	else, add "net.ipv4.conf.all.send_redirects = 0" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.send_redirects")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.send_redirects\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.send_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_send_redirects

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.all.send_redirects.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_send_redirects

- name: Comment out any occurrences of net.ipv4.conf.all.send_redirects from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.all.send_redirects
    replace: '#net.ipv4.conf.all.send_redirects'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_send_redirects

- name: Ensure sysctl net.ipv4.conf.all.send_redirects is set to 0
  sysctl:
    name: net.ipv4.conf.all.send_redirects
    value: '0'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_all_send_redirects

Rule Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default [ref]

To set the runtime status of the net.ipv4.conf.default.send_redirects kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.conf.default.send_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.conf.default.send_redirects = 0

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_send_redirects

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9
cjis	5.10.1.1
cobit5	APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1
nist	CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a)
nist-csf	DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12
pcidss4	1.4.5, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.conf.default.send_redirects from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.send_redirects.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.conf.default.send_redirects" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"


#
# Set runtime for net.ipv4.conf.default.send_redirects
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.conf.default.send_redirects="0"
fi

#
# If net.ipv4.conf.default.send_redirects present in /etc/sysctl.conf, change value to "0"
#	else, add "net.ipv4.conf.default.send_redirects = 0" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.send_redirects")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.send_redirects\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.send_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_send_redirects

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.conf.default.send_redirects.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_send_redirects

- name: Comment out any occurrences of net.ipv4.conf.default.send_redirects from config
    files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.conf.default.send_redirects
    replace: '#net.ipv4.conf.default.send_redirects'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_send_redirects

- name: Ensure sysctl net.ipv4.conf.default.send_redirects is set to 0
  sysctl:
    name: net.ipv4.conf.default.send_redirects
    value: '0'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.1
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_conf_default_send_redirects

Rule Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces [ref]

To set the runtime status of the net.ipv4.ip_forward kernel parameter, run the following command:

$ sudo sysctl -w net.ipv4.ip_forward=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

net.ipv4.ip_forward = 0

Warning: Certain technologies such as virtual machines, containers, etc. rely on IPv4 forwarding to enable and use networking. Disabling IPv4 forwarding would cause those technologies to stop working. Therefore, this rule should not be used in profiles or benchmarks that target usage of IPv4 forwarding.

Rationale:

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this capability is used when not required, system network information may be unnecessarily transmitted across the network.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_ip_forward

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9
cobit5	APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06
cui	3.1.20
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6
iso27001-2013	A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2
nerc-cip	CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1
nist	CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a)
nist-csf	DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4
pcidss	Req-1.3.1, Req-1.3.2
os-srg	SRG-OS-000480-GPOS-00227
anssi	R12
pcidss4	1.4.3, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of net.ipv4.ip_forward from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.ip_forward.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "net.ipv4.ip_forward" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"


#
# Set runtime for net.ipv4.ip_forward
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w net.ipv4.ip_forward="0"
fi

#
# If net.ipv4.ip_forward present in /etc/sysctl.conf, change value to "0"
#	else, add "net.ipv4.ip_forward = 0" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.ip_forward")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.ip_forward\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.ip_forward\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.3.1
  - PCI-DSS-Req-1.3.2
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_ip_forward

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*net.ipv4.ip_forward.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.3.1
  - PCI-DSS-Req-1.3.2
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_ip_forward

- name: Comment out any occurrences of net.ipv4.ip_forward from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*net.ipv4.ip_forward
    replace: '#net.ipv4.ip_forward'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.3.1
  - PCI-DSS-Req-1.3.2
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_ip_forward

- name: Ensure sysctl net.ipv4.ip_forward is set to 0
  sysctl:
    name: net.ipv4.ip_forward
    value: '0'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.20
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-SC-5
  - NIST-800-53-SC-7(a)
  - PCI-DSS-Req-1.3.1
  - PCI-DSS-Req-1.3.2
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.3
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_net_ipv4_ip_forward

Group Uncommon Network Protocols Group contains 2 rules

[ref] The system includes support for several network protocols which are not commonly used. Although security vulnerabilities in kernel networking code are not frequently discovered, the consequences can be dramatic. Ensuring uncommon network protocols are disabled reduces the system's risk to attacks targeted at its implementation of those protocols.

Warning: Although these protocols are not commonly used, avoid disruption in your network environment by ensuring they are not needed prior to disabling them.

Rule Disable DCCP Support [ref]

The Datagram Congestion Control Protocol (DCCP) is a relatively new transport layer protocol, designed to support streaming media and telephony. To configure the system to prevent the dccp kernel module from being loaded, add the following line to the file /etc/modprobe.d/dccp.conf:

install dccp /bin/false

Rationale:

Disabling DCCP protects the system against exploitation of any flaws in its implementation.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_kernel_module_dccp_disabled

References:

cis-csc	11, 14, 3, 9
cjis	5.10.1
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.4.6
disa	CCI-001958
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3
pcidss	Req-1.4.2
os-srg	SRG-OS-000096-GPOS-00050, SRG-OS-000378-GPOS-00163
pcidss4	1.4.2, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if LC_ALL=C grep -q -m 1 "^install dccp" /etc/modprobe.d/dccp.conf ; then
	
	sed -i 's#^install dccp.*#install dccp /bin/false#g' /etc/modprobe.d/dccp.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/dccp.conf
	echo "install dccp /bin/false" >> /etc/modprobe.d/dccp.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-1.4.2
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - kernel_module_dccp_disabled
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required

- name: Ensure kernel module 'dccp' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/dccp.conf
    regexp: install\s+dccp
    line: install dccp /bin/false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-1.4.2
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - kernel_module_dccp_disabled
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required

Rule Disable SCTP Support [ref]

The Stream Control Transmission Protocol (SCTP) is a transport layer protocol, designed to support the idea of message-oriented communication, with several streams of messages within one connection. To configure the system to prevent the sctp kernel module from being loaded, add the following line to the file /etc/modprobe.d/sctp.conf:

install sctp /bin/false

Rationale:

Disabling SCTP protects the system against exploitation of any flaws in its implementation.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_kernel_module_sctp_disabled

References:

cis-csc	11, 14, 3, 9
cjis	5.10.1
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.4.6
disa	CCI-000381
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3
pcidss	Req-1.4.2
os-srg	SRG-OS-000095-GPOS-00049, SRG-OS-000480-GPOS-00227
pcidss4	1.4.2, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if LC_ALL=C grep -q -m 1 "^install sctp" /etc/modprobe.d/sctp.conf ; then
	
	sed -i 's#^install sctp.*#install sctp /bin/false#g' /etc/modprobe.d/sctp.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/sctp.conf
	echo "install sctp /bin/false" >> /etc/modprobe.d/sctp.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.10.1
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-1.4.2
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - kernel_module_sctp_disabled
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required

- name: Ensure kernel module 'sctp' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/sctp.conf
    regexp: install\s+sctp
    line: install sctp /bin/false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-1.4.2
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.2
  - disable_strategy
  - kernel_module_sctp_disabled
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required

Group Wireless Networking Group contains 1 group and 3 rules

[ref] Wireless networking, such as 802.11 (WiFi) and Bluetooth, can present a security risk to sensitive or classified systems and networks. Wireless networking hardware is much more likely to be included in laptop or portable systems than in desktops or servers.

Removal of hardware provides the greatest assurance that the wireless capability remains disabled. Acquisition policies often include provisions to prevent the purchase of equipment that will be used in sensitive spaces and includes wireless capabilities. If it is impractical to remove the wireless hardware, and policy permits the device to enter sensitive spaces as long as wireless is disabled, efforts should instead focus on disabling wireless capability via software.

Group Disable Wireless Through Software Configuration Group contains 3 rules

[ref] If it is impossible to remove the wireless hardware from the device in question, disable as much of it as possible through software. The following methods can disable software support for wireless networking, but note that these methods do not prevent malicious software or careless users from re-activating the devices.

Rule Disable Bluetooth Service [ref]

The bluetooth service can be disabled with the following command:

$ sudo systemctl mask --now bluetooth.service

$ sudo service bluetooth stop

Rationale:

Disabling the bluetooth service prevents the system from attempting connections to Bluetooth devices, which entails some security risk. Nevertheless, variation in this risk decision may be expected due to the utility of Bluetooth connectivity and its limited range.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_bluetooth_disabled

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
cui	3.1.16
disa	CCI-000085, CCI-001551
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'bluetooth.service'
"$SYSTEMCTL_EXEC" disable 'bluetooth.service'
"$SYSTEMCTL_EXEC" mask 'bluetooth.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files bluetooth.socket; then
    "$SYSTEMCTL_EXEC" stop 'bluetooth.socket'
    "$SYSTEMCTL_EXEC" mask 'bluetooth.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'bluetooth.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
masked = ["bluetooth"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_bluetooth_disabled

- name: Disable Bluetooth Service - Collect systemd Services Present in the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_bluetooth_disabled

- name: Disable Bluetooth Service - Ensure bluetooth.service is Masked
  ansible.builtin.systemd:
    name: bluetooth.service
    state: stopped
    enabled: false
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - service_exists.stdout_lines is search("bluetooth.service", multiline=True)
  tags:
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_bluetooth_disabled

- name: Unit Socket Exists - bluetooth.socket
  ansible.builtin.command: systemctl -q list-unit-files bluetooth.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_bluetooth_disabled

- name: Disable Bluetooth Service - Disable Socket bluetooth
  ansible.builtin.systemd:
    name: bluetooth.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - socket_file_exists.stdout_lines is search("bluetooth.socket", multiline=True)
  tags:
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_bluetooth_disabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include disable_bluetooth

class disable_bluetooth {
  service {'bluetooth':
    enable => false,
    ensure => 'stopped',
  }
}

Rule Disable Bluetooth Kernel Module [ref]

The kernel's module loading system can be configured to prevent loading of the Bluetooth module. Add the following to the appropriate /etc/modprobe.d configuration file to prevent the loading of the Bluetooth module:

install bluetooth /bin/true

Rationale:

If Bluetooth functionality must be disabled, preventing the kernel from loading the kernel module provides an additional safeguard against its activation.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_kernel_module_bluetooth_disabled

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cjis	5.13.1.3
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
cui	3.1.16
disa	CCI-001443, CCI-000381
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000095-GPOS-00049, SRG-OS-000300-GPOS-00118

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if LC_ALL=C grep -q -m 1 "^install bluetooth" /etc/modprobe.d/bluetooth.conf ; then
	
	sed -i 's#^install bluetooth.*#install bluetooth /bin/false#g' /etc/modprobe.d/bluetooth.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/bluetooth.conf
	echo "install bluetooth /bin/false" >> /etc/modprobe.d/bluetooth.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.13.1.3
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - kernel_module_bluetooth_disabled
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required

- name: Ensure kernel module 'bluetooth' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/bluetooth.conf
    regexp: install\s+bluetooth
    line: install bluetooth /bin/false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.13.1.3
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - kernel_module_bluetooth_disabled
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required

Rule Deactivate Wireless Network Interfaces [ref]

Deactivating wireless network interfaces should prevent normal usage of the wireless capability.

Configure the system to disable all wireless network interfaces with the following command:

$ sudo nmcli radio all off

Rationale:

The use of wireless networking can introduce many different attack vectors into the organization's network. Common attack vectors such as malicious association and ad hoc networks will allow an attacker to spoof a wireless access point (AP), allowing validated systems to connect to the malicious AP and enabling the attacker to monitor and record network traffic. These malicious APs can also serve to create a man-in-the-middle attack or be used to create a denial of service to valid network resources.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_wireless_disable_interfaces

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
cui	3.1.16
disa	CCI-001443, CCI-001444, CCI-002421, CCI-002418
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
ism	1315, 1319
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
pcidss	Req-1.3.3
os-srg	SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000424-GPOS-00188, SRG-OS-000481-GPOS-000481
pcidss4	1.3.3, 1.3

Remediation Shell script ⇲


if ! rpm -q --quiet "NetworkManager" ; then
    yum install -y "NetworkManager"
fi

if command -v nmcli >/dev/null 2>&1 && systemctl is-active NetworkManager >/dev/null 2>&1; then
    nmcli radio all off
fi

if command -v wicked >/dev/null 2>&1 && systemctl is-active wickedd >/dev/null 2>&1; then
  if [ -n "$(find /sys/class/net/*/ -type d -name wireless)" ]; then
    interfaces=$(find /sys/class/net/*/wireless -type d -name wireless | xargs -0 dirname | xargs basename)
    for iface in $interfaces; do
      wicked ifdown $iface
      sed -i 's/STARTMODE=.*/STARTMODE=off/' /etc/sysconfig/network/ifcfg-$iface
    done
  fi
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	unknown

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - PCI-DSS-Req-1.3.3
  - PCI-DSSv4-1.3
  - PCI-DSSv4-1.3.3
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy
  - wireless_disable_interfaces

- name: Service facts
  ansible.builtin.service_facts: null
  tags:
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - PCI-DSS-Req-1.3.3
  - PCI-DSSv4-1.3
  - PCI-DSSv4-1.3.3
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy
  - wireless_disable_interfaces

- name: Ensure NetworkManager is installed
  ansible.builtin.package:
    name: '{{ item }}'
    state: present
  with_items:
  - NetworkManager
  tags:
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - PCI-DSS-Req-1.3.3
  - PCI-DSSv4-1.3
  - PCI-DSSv4-1.3.3
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy
  - wireless_disable_interfaces

- name: NetworkManager Deactivate Wireless Network Interfaces
  command: nmcli radio wifi off
  when:
  - '''NetworkManager'' in ansible_facts.packages'
  - ansible_facts.services['NetworkManager.service'].state == 'running'
  tags:
  - NIST-800-171-3.1.16
  - NIST-800-53-AC-18(3)
  - NIST-800-53-AC-18(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - PCI-DSS-Req-1.3.3
  - PCI-DSSv4-1.3
  - PCI-DSSv4-1.3.3
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy
  - wireless_disable_interfaces

Rule Configure Multiple DNS Servers in /etc/resolv.conf [ref]

Multiple Domain Name System (DNS) Servers should be configured in /etc/resolv.conf. This provides redundant name resolution services in the event that a domain server crashes. To configure the system to contain as least 2 DNS servers, add a corresponding

nameserver
ip_address

entry in /etc/resolv.conf for each DNS server where ip_address is the IP address of a valid DNS server. For example:

search example.com
nameserver 192.168.0.1
nameserver 192.168.0.2

Warning: This rule doesn't come with a remediation, the IP addresses of local authoritative name servers need to be added by the administrator.

Rationale:

To provide availability for name resolution services, multiple redundant name servers are mandated. A failure in name resolution could lead to the failure of security functions requiring name resolution, which may include time synchronization, centralized authentication, and remote system logging.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_network_configure_name_resolution

References:

cis-csc	12, 15, 8
cobit5	APO13.01, DSS05.02
disa	CCI-000366
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.13.1.1, A.13.2.1, A.14.1.3
nist	SC-20(a), CM-6(a)
nist-csf	PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227

Rule Ensure System is Not Acting as a Network Sniffer [ref]

The system should not be acting as a network sniffer, which can capture all traffic on the network to which it is connected. Run the following to determine if any interface is running in promiscuous mode:

$ ip link | grep PROMISC

Promiscuous mode of an interface can be disabled with the following command:

$ sudo ip link set dev device_name multicast off promisc off

Rationale:

Network interfaces in promiscuous mode allow for the capture of all network traffic visible to the system. If unauthorized individuals can access these applications, it may allow them to collect information such as logon IDs, passwords, and key exchanges between systems.

If the system is being used to perform a network troubleshooting function, the use of these tools must be documented with the Information Systems Security Manager (ISSM) and restricted to only authorized personnel.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_network_sniffer_disabled

References:

cis-csc	1, 11, 14, 3, 9
cobit5	APO11.06, APO12.06, BAI03.10, BAI09.01, BAI09.02, BAI09.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.05, DSS04.05, DSS05.02, DSS05.05, DSS06.06
disa	CCI-000366
isa-62443-2009	4.2.3.4, 4.3.3.3.7, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, SR 7.8
iso27001-2013	A.11.1.2, A.11.2.4, A.11.2.5, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.16.1.6, A.8.1.1, A.8.1.2, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a), CM-7(2), MA-3
nist-csf	DE.DP-5, ID.AM-1, PR.IP-1, PR.MA-1, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227
pcidss4	1.4.5, 1.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

for interface in $(ip -o link show | cut -d ":" -f 2); do
    ip link set dev $interface multicast off promisc off
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Ensure System is Not Acting as a Network Sniffer - Gather network interfaces
  ansible.builtin.command:
    cmd: ip -o link show
  register: network_interfaces
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(2)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MA-3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - low_complexity
  - low_disruption
  - medium_severity
  - network_sniffer_disabled
  - no_reboot_needed
  - restrict_strategy

- name: Ensure System is Not Acting as a Network Sniffer - Disable promiscuous mode
  ansible.builtin.command:
    cmd: ip link set dev {{ item.split(':')[1] }} multicast off promisc off
  loop: '{{ network_interfaces.stdout_lines }}'
  when:
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  - network_interfaces.stdout_lines is defined and "item.split(':') | length == 3"
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(2)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MA-3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.5
  - low_complexity
  - low_disruption
  - medium_severity
  - network_sniffer_disabled
  - no_reboot_needed
  - restrict_strategy

Group File Permissions and Masks Group contains 7 groups and 19 rules

[ref] Traditional Unix security relies heavily on file and directory permissions to prevent unauthorized users from reading or modifying files to which they should not have access.

Several of the commands in this section search filesystems for files or directories with certain characteristics, and are intended to be run on every local partition on a given system. When the variable PART appears in one of the commands below, it means that the command is intended to be run repeatedly, with the name of each local partition substituted for PART in turn.

The following command prints a list of all xfs partitions on the local system, which is the default filesystem for Red Hat Virtualization 4 installations:

$ mount -t xfs | awk '{print $3}'

For any systems that use a different local filesystem type, modify this command as appropriate.

Group Verify Permissions on Important Files and Directories Group contains 3 rules

[ref] Permissions for many files on a system must be set restrictively to ensure sensitive information is properly protected. This section discusses important permission restrictions which can be verified to ensure that no harmful discrepancies have arisen.

Rule Ensure All World-Writable Directories Are Owned by a System Account [ref]

All directories in local partitions which are world-writable should be owned by root or another system account. If any world-writable directories are not owned by a system account, this should be investigated. Following this, the files should be deleted or assigned to an appropriate owner.

Warning: This rule can take a long time to perform the check and might consume a considerable amount of resources depending on the number of directories present on the system. It is not a problem in most cases, but especially systems with a large number of directories can be affected. See https://access.redhat.com/articles/6999111.

Rationale:

Allowing a user account to own a world-writable directory is undesirable because it allows the owner of that directory to remove or replace any files that may be placed in the directory by other users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_dir_perms_world_writable_system_owned

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
disa	CCI-000366
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.DS-5
os-srg	SRG-OS-000480-GPOS-00227

Rule Ensure All Files Are Owned by a Group [ref]

If any file is not group-owned by a valid defined group, the cause of the lack of group-ownership must be investigated. Following this, those files should be deleted or assigned to an appropriate group. The groups need to be defined in /etc/group or in /usr/lib/group if nss-altfiles are configured to be used in /etc/nsswitch.conf. Locate the mount points related to local devices by the following command:

$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)

For all mount points listed by the previous command, it is necessary to search for files which do not belong to a valid group using the following command:

$ sudo find MOUNTPOINT -xdev -nogroup 2>/dev/null

Warning: This rule only considers local groups as valid groups. If you have your groups defined outside /etc/group or /usr/lib/group, the rule won't consider those.

Warning: This rule can take a long time to perform the check and might consume a considerable amount of resources depending on the number of files present on the system. It is not a problem in most cases, but especially systems with a large number of files can be affected. See https://access.redhat.com/articles/6999111.

Rationale:

Unowned files do not directly imply a security problem, but they are generally a sign that something is amiss. They may be caused by an intruder, by incorrect software installation or draft software removal, or by failure to remove all files belonging to a deleted account, or other similar cases. The files should be repaired so they will not cause problems when accounts are created in the future, and the cause should be discovered and addressed.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permissions_ungroupowned

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10
disa	CCI-000366
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nist	CM-6(a), AC-6(1)
nist-csf	PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R53
pcidss4	2.2.6, 2.2

Rule Ensure All Files Are Owned by a User [ref]

If any files are not owned by a user, then the cause of their lack of ownership should be investigated. Following this, the files should be deleted or assigned to an appropriate user. Locate the mount points related to local devices by the following command:

$ findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)

For all mount points listed by the previous command, it is necessary to search for files which do not belong to a valid user using the following command:

$ sudo find MOUNTPOINT -xdev -nouser 2>/dev/null

Warning: For this rule to evaluate centralized user accounts, getent must be working properly so that running the command

getent passwd

returns a list of all users in your organization. If using the System Security Services Daemon (SSSD),

enumerate = true

must be configured in your organization's domain to return a complete list of users

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_no_files_unowned_by_user

References:

cis-csc	11, 12, 13, 14, 15, 16, 18, 3, 5, 9
cobit5	APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06
disa	CCI-000366
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227
anssi	R53
pcidss4	2.2.6, 2.2

Group Restrict Dynamic Mounting and Unmounting of Filesystems Group contains 7 rules

[ref] Linux includes a number of facilities for the automated addition and removal of filesystems on a running system. These facilities may be necessary in many environments, but this capability also carries some risk -- whether direct risk from allowing users to introduce arbitrary filesystems, or risk that software flaws in the automated mount facility itself could allow an attacker to compromise the system.

This command can be used to list the types of filesystems that are available to the currently executing kernel:

$ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'

If these filesystems are not required then they can be explicitly disabled in a configuratio file in /etc/modprobe.d.

Rule Disable the Automounter [ref]

The autofs daemon mounts and unmounts filesystems, such as user home directories shared via NFS, on demand. In addition, autofs can be used to handle removable media, and the default configuration provides the cdrom device as /misc/cd. However, this method of providing access to removable media is not common, so autofs can almost always be disabled if NFS is not in use. Even if NFS is required, it may be possible to configure filesystem mounts statically by editing /etc/fstab rather than relying on the automounter.

The autofs service can be disabled with the following command:

$ sudo systemctl mask --now autofs.service

Rationale:

Disabling the automounter permits the administrator to statically control filesystem mounting through /etc/fstab.

Additionally, automatically mounting filesystems permits easy introduction of unknown devices, thereby facilitating malicious activity.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_autofs_disabled

References:

cis-csc	1, 12, 15, 16, 5
cobit5	APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.4.6
disa	CCI-000778, CCI-000366, CCI-001958
hipaa	164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6
iso27001-2013	A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-7(a), CM-7(b), CM-6(a), MP-7
nist-csf	PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if ( rpm --quiet -q autofs && rpm --quiet -q kernel ); then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'autofs.service'
"$SYSTEMCTL_EXEC" disable 'autofs.service'
"$SYSTEMCTL_EXEC" mask 'autofs.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files autofs.socket; then
    "$SYSTEMCTL_EXEC" stop 'autofs.socket'
    "$SYSTEMCTL_EXEC" mask 'autofs.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'autofs.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
masked = ["autofs"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_autofs_disabled

- name: Disable the Automounter - Collect systemd Services Present in the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: ( "autofs" in ansible_facts.packages and "kernel" in ansible_facts.packages
    )
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_autofs_disabled

- name: Disable the Automounter - Ensure autofs.service is Masked
  ansible.builtin.systemd:
    name: autofs.service
    state: stopped
    enabled: false
    masked: true
  when:
  - ( "autofs" in ansible_facts.packages and "kernel" in ansible_facts.packages )
  - service_exists.stdout_lines is search("autofs.service", multiline=True)
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_autofs_disabled

- name: Unit Socket Exists - autofs.socket
  ansible.builtin.command: systemctl -q list-unit-files autofs.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: ( "autofs" in ansible_facts.packages and "kernel" in ansible_facts.packages
    )
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_autofs_disabled

- name: Disable the Automounter - Disable Socket autofs
  ansible.builtin.systemd:
    name: autofs.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - ( "autofs" in ansible_facts.packages and "kernel" in ansible_facts.packages )
  - socket_file_exists.stdout_lines is search("autofs.socket", multiline=True)
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_autofs_disabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include disable_autofs

class disable_autofs {
  service {'autofs':
    enable => false,
    ensure => 'stopped',
  }
}

Rule Disable Mounting of cramfs [ref]

To configure the system to prevent the cramfs kernel module from being loaded, add the following line to the file /etc/modprobe.d/cramfs.conf:

install cramfs /bin/false

This effectively prevents usage of this uncommon filesystem. The cramfs filesystem type is a compressed read-only Linux filesystem embedded in small footprint systems. A cramfs image can be used without having to first decompress the image.

Rationale:

Removing support for unneeded filesystem types reduces the local attack surface of the server.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_kernel_module_cramfs_disabled

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.4.6
disa	CCI-000381
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3
os-srg	SRG-OS-000095-GPOS-00049

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if LC_ALL=C grep -q -m 1 "^install cramfs" /etc/modprobe.d/cramfs.conf ; then
	
	sed -i 's#^install cramfs.*#install cramfs /bin/false#g' /etc/modprobe.d/cramfs.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/cramfs.conf
	echo "install cramfs /bin/false" >> /etc/modprobe.d/cramfs.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_cramfs_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

- name: Ensure kernel module 'cramfs' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/cramfs.conf
    regexp: install\s+cramfs
    line: install cramfs /bin/false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_cramfs_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

Rule Disable Mounting of freevxfs [ref]

To configure the system to prevent the freevxfs kernel module from being loaded, add the following line to the file /etc/modprobe.d/freevxfs.conf:

install freevxfs /bin/false

This effectively prevents usage of this uncommon filesystem.

Rationale:

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_kernel_module_freevxfs_disabled

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.4.6
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if LC_ALL=C grep -q -m 1 "^install freevxfs" /etc/modprobe.d/freevxfs.conf ; then
	
	sed -i 's#^install freevxfs.*#install freevxfs /bin/false#g' /etc/modprobe.d/freevxfs.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/freevxfs.conf
	echo "install freevxfs /bin/false" >> /etc/modprobe.d/freevxfs.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_freevxfs_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

- name: Ensure kernel module 'freevxfs' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/freevxfs.conf
    regexp: install\s+freevxfs
    line: install freevxfs /bin/false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_freevxfs_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

Rule Disable Mounting of hfs [ref]

To configure the system to prevent the hfs kernel module from being loaded, add the following line to the file /etc/modprobe.d/hfs.conf:

install hfs /bin/false

This effectively prevents usage of this uncommon filesystem.

Rationale:

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_kernel_module_hfs_disabled

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.4.6
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if LC_ALL=C grep -q -m 1 "^install hfs" /etc/modprobe.d/hfs.conf ; then
	
	sed -i 's#^install hfs.*#install hfs /bin/false#g' /etc/modprobe.d/hfs.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/hfs.conf
	echo "install hfs /bin/false" >> /etc/modprobe.d/hfs.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_hfs_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

- name: Ensure kernel module 'hfs' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/hfs.conf
    regexp: install\s+hfs
    line: install hfs /bin/false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_hfs_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

Rule Disable Mounting of hfsplus [ref]

To configure the system to prevent the hfsplus kernel module from being loaded, add the following line to the file /etc/modprobe.d/hfsplus.conf:

install hfsplus /bin/false

This effectively prevents usage of this uncommon filesystem.

Rationale:

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_kernel_module_hfsplus_disabled

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.4.6
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if LC_ALL=C grep -q -m 1 "^install hfsplus" /etc/modprobe.d/hfsplus.conf ; then
	
	sed -i 's#^install hfsplus.*#install hfsplus /bin/false#g' /etc/modprobe.d/hfsplus.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/hfsplus.conf
	echo "install hfsplus /bin/false" >> /etc/modprobe.d/hfsplus.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_hfsplus_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

- name: Ensure kernel module 'hfsplus' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/hfsplus.conf
    regexp: install\s+hfsplus
    line: install hfsplus /bin/false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_hfsplus_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

Rule Disable Mounting of jffs2 [ref]

To configure the system to prevent the jffs2 kernel module from being loaded, add the following line to the file /etc/modprobe.d/jffs2.conf:

install jffs2 /bin/false

This effectively prevents usage of this uncommon filesystem.

Rationale:

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_kernel_module_jffs2_disabled

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
cui	3.4.6
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if LC_ALL=C grep -q -m 1 "^install jffs2" /etc/modprobe.d/jffs2.conf ; then
	
	sed -i 's#^install jffs2.*#install jffs2 /bin/false#g' /etc/modprobe.d/jffs2.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/jffs2.conf
	echo "install jffs2 /bin/false" >> /etc/modprobe.d/jffs2.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_jffs2_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

- name: Ensure kernel module 'jffs2' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/jffs2.conf
    regexp: install\s+jffs2
    line: install jffs2 /bin/false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - kernel_module_jffs2_disabled
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required

Rule Disable Modprobe Loading of USB Storage Driver [ref]

To prevent USB storage devices from being used, configure the kernel module loading system to prevent automatic loading of the USB storage driver. To configure the system to prevent the usb-storage kernel module from being loaded, add the following line to the file /etc/modprobe.d/usb-storage.conf:

install usb-storage /bin/false

This will prevent the modprobe program from loading the usb-storage module, but will not prevent an administrator (or another program) from using the insmod program to load the module manually.

Rationale:

USB storage devices such as thumb drives can be used to introduce malicious software.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_kernel_module_usb-storage_disabled

References:

cis-csc	1, 12, 15, 16, 5
cobit5	APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.1.21
disa	CCI-000778, CCI-001958, CCI-003959
hipaa	164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6
iso27001-2013	A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-7(a), CM-7(b), CM-6(a), MP-7
nist-csf	PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227
app-srg-ctr	SRG-APP-000141-CTR-000315
pcidss4	3.4.2, 3.4

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if LC_ALL=C grep -q -m 1 "^install usb-storage" /etc/modprobe.d/usb-storage.conf ; then
	
	sed -i 's#^install usb-storage.*#install usb-storage /bin/false#g' /etc/modprobe.d/usb-storage.conf
else
	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/usb-storage.conf
	echo "install usb-storage /bin/false" >> /etc/modprobe.d/usb-storage.conf
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.21
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - PCI-DSSv4-3.4
  - PCI-DSSv4-3.4.2
  - disable_strategy
  - kernel_module_usb-storage_disabled
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required

- name: Ensure kernel module 'usb-storage' is disabled
  lineinfile:
    create: true
    dest: /etc/modprobe.d/usb-storage.conf
    regexp: install\s+usb-storage
    line: install usb-storage /bin/false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.21
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - PCI-DSSv4-3.4
  - PCI-DSSv4-3.4.2
  - disable_strategy
  - kernel_module_usb-storage_disabled
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required

Group Restrict Partition Mount Options Group contains 4 rules

[ref] System partitions can be mounted with certain options that limit what files on those partitions can do. These options are set in the /etc/fstab configuration file, and can be used to make certain types of malicious behavior more difficult.

Rule Add nosuid Option to /home [ref]

The nosuid mount option can be used to prevent execution of setuid programs in /home. The SUID and SGID permissions should not be required in these user data directories. Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of /home.

Rationale:

The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from user home directory partitions.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_mount_option_home_nosuid

References:

cis-csc	11, 13, 14, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06
disa	CCI-000366, CCI-001764
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7
nist-csf	PR.IP-1, PR.PT-2, PR.PT-3
os-srg	SRG-OS-000368-GPOS-00154, SRG-OS-000480-GPOS-00227
anssi	R28

Remediation Shell script ⇲

Reboot:	false

# Remediation is applicable only in certain platforms
if ( ! ( { rpm --quiet -q kernel ;} && { rpm --quiet -q rpm-ostree ;} && { rpm --quiet -q bootc ;} ) && ! ( [ -f /.dockerenv ] || [ -f /run/.containerenv ] ) ) && { findmnt --kernel "/home" > /dev/null || findmnt --fstab "/home" > /dev/null; }; then

function perform_remediation {
    
        # the mount point /home has to be defined in /etc/fstab
        # before this remediation can be executed. In case it is not defined, the
        # remediation aborts and no changes regarding the mount point are done.
        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" "/home")"

    grep "$mount_point_match_regexp" -q /etc/fstab \
        || { echo "The mount point '/home' is not even in /etc/fstab, so we can't set up mount options" >&2;
                echo "Not remediating, because there is no record of /home in /etc/fstab" >&2; return 1; }
    


    mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /home)"

    # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
    if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
        # runtime opts without some automatic kernel/userspace-added defaults
        previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                    | sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
        [ "$previous_mount_opts" ] && previous_mount_opts+=","
        # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
        # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
        fs_type=""
        if [  "$fs_type" == "iso9660" ] ; then
            previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
        fi
        echo " /home  defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
    # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
    elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nosuid"; then
        previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
        sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
    fi


    if mkdir -p "/home"; then
        if mountpoint -q "/home"; then
            mount -o remount --target "/home"
        fi
    fi
}

perform_remediation

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	high
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_home_nosuid
  - no_reboot_needed

- name: 'Add nosuid Option to /home: Check information associated to mountpoint'
  command: findmnt --fstab '/home'
  register: device_name
  failed_when: device_name.rc > 1
  changed_when: false
  when:
  - ( not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages ) and not ( ansible_virtualization_type
    in ["docker", "lxc", "openvz", "podman", "container"] ) )
  - '"/home" in ansible_mounts | map(attribute="mount") | list'
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_home_nosuid
  - no_reboot_needed

- name: 'Add nosuid Option to /home: Create mount_info dictionary variable'
  set_fact:
    mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
  with_together:
  - '{{ device_name.stdout_lines[0].split() | list | lower }}'
  - '{{ device_name.stdout_lines[1].split() | list }}'
  when:
  - ( not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages ) and not ( ansible_virtualization_type
    in ["docker", "lxc", "openvz", "podman", "container"] ) )
  - '"/home" in ansible_mounts | map(attribute="mount") | list'
  - device_name.stdout is defined and device_name.stdout_lines is defined
  - (device_name.stdout | length > 0)
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_home_nosuid
  - no_reboot_needed

- name: 'Add nosuid Option to /home: If /home not mounted, craft mount_info manually'
  set_fact:
    mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
  with_together:
  - - target
    - source
    - fstype
    - options
  - - /home
    - ''
    - ''
    - defaults
  when:
  - ( not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages ) and not ( ansible_virtualization_type
    in ["docker", "lxc", "openvz", "podman", "container"] ) )
  - '"/home" in ansible_mounts | map(attribute="mount") | list'
  - ("--fstab" | length == 0)
  - device_name.stdout is defined and device_name.stdout_lines is defined
  - (device_name.stdout | length == 0)
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_home_nosuid
  - no_reboot_needed

- name: 'Add nosuid Option to /home: Make sure nosuid option is part of the to /home
    options'
  set_fact:
    mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
      }) }}'
  when:
  - ( not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages ) and not ( ansible_virtualization_type
    in ["docker", "lxc", "openvz", "podman", "container"] ) )
  - '"/home" in ansible_mounts | map(attribute="mount") | list'
  - mount_info is defined and "nosuid" not in mount_info.options
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_home_nosuid
  - no_reboot_needed

- name: 'Add nosuid Option to /home: Ensure /home is mounted with nosuid option'
  mount:
    path: /home
    src: '{{ mount_info.source }}'
    opts: '{{ mount_info.options }}'
    state: mounted
    fstype: '{{ mount_info.fstype }}'
  when:
  - ( not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages ) and not ( ansible_virtualization_type
    in ["docker", "lxc", "openvz", "podman", "container"] ) )
  - '"/home" in ansible_mounts | map(attribute="mount") | list'
  - mount_info is defined
  - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
    | length == 0)
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_home_nosuid
  - no_reboot_needed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	high
Reboot:	false
Strategy:	enable


part /home --mountoptions="nosuid"

Rule Add nodev Option to Removable Media Partitions [ref]

The nodev mount option prevents files from being interpreted as character or block devices. Legitimate character and block devices should exist only in the /dev directory on the root partition or within chroot jails built for system services. Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of any removable media partitions.

Rationale:

The only legitimate location for device files is the /dev directory located on the root partition. An exception to this is chroot jails, and it is not advised to set nodev on partitions which contain their root filesystems.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_mount_option_nodev_removable_partitions

References:

cis-csc	11, 12, 13, 14, 16, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.06, DSS05.07, DSS06.03, DSS06.06
disa	CCI-000366
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.11.2.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.7.1.1, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, A.9.2.1
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7
nist-csf	PR.AC-3, PR.AC-6, PR.IP-1, PR.PT-2, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Reboot:	false

# Remediation is applicable only in certain platforms
if ( ! ( { rpm --quiet -q kernel ;} && { rpm --quiet -q rpm-ostree ;} && { rpm --quiet -q bootc ;} ) && ! ( [ -f /.dockerenv ] || [ -f /run/.containerenv ] ) ); then

var_removable_partition='/dev/cdrom'


device_regex="^\s*$var_removable_partition\s\+"
mount_option="nodev"

if grep -q $device_regex /etc/fstab ; then
    previous_opts=$(grep $device_regex /etc/fstab | awk '{print $4}')
    sed -i "s|\($device_regex.*$previous_opts\)|\1,$mount_option|" /etc/fstab
else
    echo "Not remediating, because there is no record of $var_removable_partition in /etc/fstab" >&2
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	high
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_nodev_removable_partitions
  - no_reboot_needed
- name: XCCDF Value var_removable_partition # promote to variable
  set_fact:
    var_removable_partition: !!str /dev/cdrom
  tags:
    - always

- name: Ensure permission nodev are set on var_removable_partition
  lineinfile:
    path: /etc/fstab
    regexp: ^\s*({{ var_removable_partition }})\s+([^\s]*)\s+([^\s]*)\s+([^\s]*)(.*)$
    backrefs: true
    line: \1 \2 \3 \4,nodev \5
  when: ( not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages ) and not ( ansible_virtualization_type
    in ["docker", "lxc", "openvz", "podman", "container"] ) )
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_nodev_removable_partitions
  - no_reboot_needed

Rule Add noexec Option to Removable Media Partitions [ref]

The noexec mount option prevents the direct execution of binaries on the mounted filesystem. Preventing the direct execution of binaries from removable media (such as a USB key) provides a defense against malicious software that may be present on such untrusted media. Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of any removable media partitions.

Rationale:

Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_mount_option_noexec_removable_partitions

References:

cis-csc	11, 12, 13, 14, 16, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.06, DSS05.07, DSS06.03, DSS06.06
disa	CCI-000366
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.11.2.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.7.1.1, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, A.9.2.1
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7
nist-csf	PR.AC-3, PR.AC-6, PR.IP-1, PR.PT-2, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Reboot:	false

# Remediation is applicable only in certain platforms
if ( ! ( { rpm --quiet -q kernel ;} && { rpm --quiet -q rpm-ostree ;} && { rpm --quiet -q bootc ;} ) && ! ( [ -f /.dockerenv ] || [ -f /run/.containerenv ] ) ); then

var_removable_partition='/dev/cdrom'


device_regex="^\s*$var_removable_partition\s\+"
mount_option="noexec"

if grep -q $device_regex /etc/fstab ; then
    previous_opts=$(grep $device_regex /etc/fstab | awk '{print $4}')
    sed -i "s|\($device_regex.*$previous_opts\)|\1,$mount_option|" /etc/fstab
else
    echo "Not remediating, because there is no record of $var_removable_partition in /etc/fstab" >&2
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	high
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_noexec_removable_partitions
  - no_reboot_needed
- name: XCCDF Value var_removable_partition # promote to variable
  set_fact:
    var_removable_partition: !!str /dev/cdrom
  tags:
    - always

- name: Ensure permission noexec are set on var_removable_partition
  lineinfile:
    path: /etc/fstab
    regexp: ^\s*({{ var_removable_partition }})\s+([^\s]*)\s+([^\s]*)\s+([^\s]*)(.*)$
    backrefs: true
    line: \1 \2 \3 \4,noexec \5
  when: ( not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages ) and not ( ansible_virtualization_type
    in ["docker", "lxc", "openvz", "podman", "container"] ) )
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_noexec_removable_partitions
  - no_reboot_needed

Rule Add nosuid Option to Removable Media Partitions [ref]

The nosuid mount option prevents set-user-identifier (SUID) and set-group-identifier (SGID) permissions from taking effect. These permissions allow users to execute binaries with the same permissions as the owner and group of the file respectively. Users should not be allowed to introduce SUID and SGID files into the system via partitions mounted from removeable media. Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of any removable media partitions.

Rationale:

The presence of SUID and SGID executables should be tightly controlled. Allowing users to introduce SUID or SGID binaries from partitions mounted off of removable media would allow them to introduce their own highly-privileged programs.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_mount_option_nosuid_removable_partitions

References:

cis-csc	11, 12, 13, 14, 15, 16, 18, 3, 5, 8, 9
cobit5	APO01.06, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.06, DSS05.07, DSS06.02, DSS06.03, DSS06.06
disa	CCI-000366
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.11.2.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7
nist-csf	PR.AC-3, PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-2, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Reboot:	false

# Remediation is applicable only in certain platforms
if ( ! ( { rpm --quiet -q kernel ;} && { rpm --quiet -q rpm-ostree ;} && { rpm --quiet -q bootc ;} ) && ! ( [ -f /.dockerenv ] || [ -f /run/.containerenv ] ) ); then

var_removable_partition='/dev/cdrom'


device_regex="^\s*$var_removable_partition\s\+"
mount_option="nosuid"

if grep -q $device_regex /etc/fstab ; then
    previous_opts=$(grep $device_regex /etc/fstab | awk '{print $4}')
    sed -i "s|\($device_regex.*$previous_opts\)|\1,$mount_option|" /etc/fstab
else
    echo "Not remediating, because there is no record of $var_removable_partition in /etc/fstab" >&2
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	high
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_nosuid_removable_partitions
  - no_reboot_needed
- name: XCCDF Value var_removable_partition # promote to variable
  set_fact:
    var_removable_partition: !!str /dev/cdrom
  tags:
    - always

- name: Ensure permission nosuid are set on var_removable_partition
  lineinfile:
    path: /etc/fstab
    regexp: ^\s*({{ var_removable_partition }})\s+([^\s]*)\s+([^\s]*)\s+([^\s]*)(.*)$
    backrefs: true
    line: \1 \2 \3 \4,nosuid \5
  when: ( not ( "kernel" in ansible_facts.packages and "rpm-ostree" in ansible_facts.packages
    and "bootc" in ansible_facts.packages ) and not ( ansible_virtualization_type
    in ["docker", "lxc", "openvz", "podman", "container"] ) )
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-MP-7
  - configure_strategy
  - high_disruption
  - low_complexity
  - medium_severity
  - mount_option_nosuid_removable_partitions
  - no_reboot_needed

Group Restrict Programs from Dangerous Execution Patterns Group contains 3 groups and 5 rules

[ref] The recommendations in this section are designed to ensure that the system's features to protect against potentially dangerous program execution are activated. These protections are applied at the system initialization or kernel level, and defend against certain types of badly-configured or compromised programs.

Group Disable Core Dumps Group contains 1 rule

[ref] A core dump file is the memory image of an executable program when it was terminated by the operating system due to errant behavior. In most cases, only software developers legitimately need to access these files. The core dump files may also contain sensitive information, or unnecessarily occupy large amounts of disk space.

Once a hard limit is set in /etc/security/limits.conf, or to a file within the /etc/security/limits.d/ directory, a user cannot increase that limit within his or her own session. If access to core dumps is required, consider restricting them to only certain users or groups. See the limits.conf man page for more information.

The core dumps of setuid programs are further protected. The sysctl variable fs.suid_dumpable controls whether the kernel allows core dumps from these programs at all. The default value of 0 is recommended.

Rule Disable Core Dumps for SUID programs [ref]

To set the runtime status of the fs.suid_dumpable kernel parameter, run the following command:

$ sudo sysctl -w fs.suid_dumpable=0

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

fs.suid_dumpable = 0

Rationale:

The core dump of a setuid program is more likely to contain sensitive data, as the program itself runs with greater privileges than the user who initiated execution of the program. Disabling the ability for any setuid program to write a core file decreases the risk of unauthorized access of such data.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_fs_suid_dumpable

References:

hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
nist	SI-11(a), SI-11(b)
anssi	R14
pcidss4	3.3.1.1, 3.3.1, 3.3

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of fs.suid_dumpable from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*fs.suid_dumpable.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "fs.suid_dumpable" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"


#
# Set runtime for fs.suid_dumpable
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w fs.suid_dumpable="0"
fi

#
# If fs.suid_dumpable present in /etc/sysctl.conf, change value to "0"
#	else, add "fs.suid_dumpable = 0" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^fs.suid_dumpable")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "0"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^fs.suid_dumpable\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^fs.suid_dumpable\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-SI-11(a)
  - NIST-800-53-SI-11(b)
  - PCI-DSSv4-3.3
  - PCI-DSSv4-3.3.1
  - PCI-DSSv4-3.3.1.1
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_fs_suid_dumpable

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*fs.suid_dumpable.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-SI-11(a)
  - NIST-800-53-SI-11(b)
  - PCI-DSSv4-3.3
  - PCI-DSSv4-3.3.1
  - PCI-DSSv4-3.3.1.1
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_fs_suid_dumpable

- name: Comment out any occurrences of fs.suid_dumpable from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*fs.suid_dumpable
    replace: '#fs.suid_dumpable'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-SI-11(a)
  - NIST-800-53-SI-11(b)
  - PCI-DSSv4-3.3
  - PCI-DSSv4-3.3.1
  - PCI-DSSv4-3.3.1.1
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_fs_suid_dumpable

- name: Ensure sysctl fs.suid_dumpable is set to 0
  sysctl:
    name: fs.suid_dumpable
    value: '0'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-SI-11(a)
  - NIST-800-53-SI-11(b)
  - PCI-DSSv4-3.3
  - PCI-DSSv4-3.3.1
  - PCI-DSSv4-3.3.1.1
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_fs_suid_dumpable

Group Enable ExecShield Group contains 2 rules

[ref] ExecShield describes kernel features that provide protection against exploitation of memory corruption errors such as buffer overflows. These features include random placement of the stack and other memory regions, prevention of execution in memory that should only hold data, and special handling of text buffers. These protections are enabled by default on 32-bit systems and controlled through sysctl variables kernel.exec-shield and kernel.randomize_va_space. On the latest 64-bit systems, kernel.exec-shield cannot be enabled or disabled with sysctl.

Rule Enable ExecShield via sysctl [ref]

By default on Red Hat Virtualization 4 64-bit systems, ExecShield is enabled and can only be disabled if the hardware does not support ExecShield or is disabled in /etc/default/grub. For Red Hat Virtualization 4 32-bit systems, sysctl can be used to enable ExecShield.

Rationale:

ExecShield uses the segmentation feature on all x86 systems to prevent execution in memory higher than a certain address. It writes an address as a limit in the code segment descriptor, to control where code can be executed, on a per-process basis. When the kernel places a process's memory regions such as the stack and heap higher than this address, the hardware prevents execution in that address range. This is enabled by default on the latest Red Hat and Fedora systems if supported by the hardware.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_kernel_exec_shield

References:

cis-csc	12, 15, 8
cobit5	APO13.01, DSS05.02
cui	3.1.7
disa	CCI-002824
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.13.1.1, A.13.2.1, A.14.1.3
nist	SC-39, CM-6(a)
nist-csf	PR.PT-4
os-srg	SRG-OS-000433-GPOS-00192

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ "$(getconf LONG_BIT)" = "32" ] ; then
  #
  # Set runtime for kernel.exec-shield
  #
  sysctl -q -n -w kernel.exec-shield=1

  #
  # If kernel.exec-shield present in /etc/sysctl.conf, change value to "1"
  #	else, add "kernel.exec-shield = 1" to /etc/sysctl.conf
  #
  # Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.exec-shield")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.exec-shield\\>" "/etc/sysctl.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^kernel.exec-shield\\>.*/$escaped_formatted_output/gi" "/etc/sysctl.conf"
else
    if [[ -s "/etc/sysctl.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/sysctl.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/sysctl.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/sysctl.conf"
fi
fi

if [ "$(getconf LONG_BIT)" = "64" ] ; then
    
grubby --update-kernel=ALL --remove-args=noexec

fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-39
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
  - sysctl_kernel_exec_shield

- name: Set 32bit architecture for kernel exec-shield tasks
  set_fact:
    kexec_arch: b32
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-39
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
  - sysctl_kernel_exec_shield

- name: Set 64bit architecture for kernel exec-shield tasks
  set_fact:
    kexec_arch: b64
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-39
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
  - sysctl_kernel_exec_shield

- name: Ensure sysctl kernel.exec-shield is set to 1
  sysctl:
    name: kernel.exec-shield
    value: '1'
    state: present
    reload: true
  when:
  - '"kernel" in ansible_facts.packages'
  - kexec_arch == "b32"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-39
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
  - sysctl_kernel_exec_shield

- name: Update grub defaults and the bootloader menu
  command: /sbin/grubby --update-kernel=ALL --remove-args="noexec"
  when:
  - '"kernel" in ansible_facts.packages'
  - kexec_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-39
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
  - sysctl_kernel_exec_shield

Rule Enable Randomized Layout of Virtual Address Space [ref]

To set the runtime status of the kernel.randomize_va_space kernel parameter, run the following command:

$ sudo sysctl -w kernel.randomize_va_space=2

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

kernel.randomize_va_space = 2

Rationale:

Address space layout randomization (ASLR) makes it more difficult for an attacker to predict the location of attack code they have introduced into a process's address space during an attempt at exploitation. Additionally, ASLR makes it more difficult for an attacker to know the location of existing code in order to re-purpose it using return oriented programming (ROP) techniques.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_kernel_randomize_va_space

References:

cui	3.1.7
disa	CCI-000366, CCI-002824
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
nerc-cip	CIP-002-5 R1.1, CIP-002-5 R1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 4.1, CIP-004-6 4.2, CIP-004-6 R2.2.3, CIP-004-6 R2.2.4, CIP-004-6 R2.3, CIP-004-6 R4, CIP-005-6 R1, CIP-005-6 R1.1, CIP-005-6 R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-6 R.1.1, CIP-009-6 R4
nist	SC-30, SC-30(2), CM-6(a)
pcidss	Req-2.2.1
os-srg	SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227
app-srg-ctr	SRG-APP-000450-CTR-001105
anssi	R9
pcidss4	3.3.1.1, 3.3.1, 3.3

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of kernel.randomize_va_space from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*kernel.randomize_va_space.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "kernel.randomize_va_space" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"


#
# Set runtime for kernel.randomize_va_space
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w kernel.randomize_va_space="2"
fi

#
# If kernel.randomize_va_space present in /etc/sysctl.conf, change value to "2"
#	else, add "kernel.randomize_va_space = 2" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.randomize_va_space")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "2"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.randomize_va_space\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^kernel.randomize_va_space\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-30
  - NIST-800-53-SC-30(2)
  - PCI-DSS-Req-2.2.1
  - PCI-DSSv4-3.3
  - PCI-DSSv4-3.3.1
  - PCI-DSSv4-3.3.1.1
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_kernel_randomize_va_space

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*kernel.randomize_va_space.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-30
  - NIST-800-53-SC-30(2)
  - PCI-DSS-Req-2.2.1
  - PCI-DSSv4-3.3
  - PCI-DSSv4-3.3.1
  - PCI-DSSv4-3.3.1.1
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_kernel_randomize_va_space

- name: Comment out any occurrences of kernel.randomize_va_space from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*kernel.randomize_va_space
    replace: '#kernel.randomize_va_space'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-30
  - NIST-800-53-SC-30(2)
  - PCI-DSS-Req-2.2.1
  - PCI-DSSv4-3.3
  - PCI-DSSv4-3.3.1
  - PCI-DSSv4-3.3.1.1
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_kernel_randomize_va_space

- name: Ensure sysctl kernel.randomize_va_space is set to 2
  sysctl:
    name: kernel.randomize_va_space
    value: '2'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-30
  - NIST-800-53-SC-30(2)
  - PCI-DSS-Req-2.2.1
  - PCI-DSSv4-3.3
  - PCI-DSSv4-3.3.1
  - PCI-DSSv4-3.3.1.1
  - disable_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - reboot_required
  - sysctl_kernel_randomize_va_space

Group Enable Execute Disable (XD) or No Execute (NX) Support on x86 Systems Group contains 1 rule

[ref] Recent processors in the x86 family support the ability to prevent code execution on a per memory page basis. Generically and on AMD processors, this ability is called No Execute (NX), while on Intel processors it is called Execute Disable (XD). This ability can help prevent exploitation of buffer overflow vulnerabilities and should be activated whenever possible. Extra steps must be taken to ensure that this protection is enabled, particularly on 32-bit x86 systems. Other processors, such as Itanium and POWER, have included such support since inception and the standard kernel for those platforms supports the feature. This is enabled by default on the latest Oracle Linux, Red Hat and Fedora systems if supported by the hardware.

Rule Install PAE Kernel on Supported 32-bit x86 Systems [ref]

Systems that are using the 64-bit x86 kernel package do not need to install the kernel-PAE package because the 64-bit x86 kernel already includes this support. However, if the system is 32-bit and also supports the PAE and NX features as determined in the previous section, the kernel-PAE package should be installed to enable XD or NX support. The kernel-PAE package can be installed with the following command:

$ sudo yum install kernel-PAE

The installation process should also have configured the bootloader to load the new kernel at boot. Verify this after reboot and modify /etc/default/grub if necessary.

Warning: The kernel-PAE package should not be installed on older systems that do not support the XD or NX bit, as 8this may prevent them from booting.8

Rationale:

On 32-bit systems that support the XD or NX bit, the vendor-supplied PAE kernel is required to enable either Execute Disable (XD) or No Execute (NX) support.

Severity:

unknown

Rule ID: xccdf_org.ssgproject.content_rule_install_PAE_kernel_on_x86-32

References:

cis-csc	11, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05
cui	3.1.7
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4
nist	CM-6(a)
nist-csf	PR.IP-1
anssi	R1
pcidss4	2.2.1, 2.2

Rule Restrict Access to Kernel Message Buffer [ref]

To set the runtime status of the kernel.dmesg_restrict kernel parameter, run the following command:

$ sudo sysctl -w kernel.dmesg_restrict=1

To make sure that the setting is persistent, add the following line to a file in the directory /etc/sysctl.d:

kernel.dmesg_restrict = 1

Rationale:

Unprivileged access to the kernel syslog can expose sensitive kernel address information.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_sysctl_kernel_dmesg_restrict

References:

cui	3.1.5
disa	CCI-001082, CCI-001090
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
nist	SI-11(a), SI-11(b)
os-srg	SRG-OS-000132-GPOS-00067, SRG-OS-000138-GPOS-00069
app-srg-ctr	SRG-APP-000243-CTR-000600
anssi	R9

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# Comment out any occurrences of kernel.dmesg_restrict from /etc/sysctl.d/*.conf files

for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf; do


  # skip systemd-sysctl symlink (/etc/sysctl.d/99-sysctl.conf -> /etc/sysctl.conf)
  if [[ "$(readlink -f "$f")" == "/etc/sysctl.conf" ]]; then continue; fi

  matching_list=$(grep -P '^(?!#).*[\s]*kernel.dmesg_restrict.*$' $f | uniq )
  if ! test -z "$matching_list"; then
    while IFS= read -r entry; do
      escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
      # comment out "kernel.dmesg_restrict" matches to preserve user data
      sed -i --follow-symlinks "s/^${escaped_entry}$/# &/g" $f
    done <<< "$matching_list"
  fi
done

#
# Set sysctl config file which to save the desired value
#

SYSCONFIG_FILE="/etc/sysctl.conf"


#
# Set runtime for kernel.dmesg_restrict
#
if [[ "$OSCAP_BOOTC_BUILD" != "YES" ]] ; then
    /sbin/sysctl -q -n -w kernel.dmesg_restrict="1"
fi

#
# If kernel.dmesg_restrict present in /etc/sysctl.conf, change value to "1"
#	else, add "kernel.dmesg_restrict = 1" to /etc/sysctl.conf
#

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.dmesg_restrict")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "1"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^kernel.dmesg_restrict\\>" "${SYSCONFIG_FILE}"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^kernel.dmesg_restrict\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
else
    if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
    fi
    printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	true
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.5
  - NIST-800-53-SI-11(a)
  - NIST-800-53-SI-11(b)
  - disable_strategy
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required
  - sysctl_kernel_dmesg_restrict

- name: List /etc/sysctl.d/*.conf files
  find:
    paths:
    - /etc/sysctl.d/
    - /run/sysctl.d/
    - /usr/local/lib/sysctl.d/
    - /usr/lib/sysctl.d/
    contains: ^[\s]*kernel.dmesg_restrict.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.5
  - NIST-800-53-SI-11(a)
  - NIST-800-53-SI-11(b)
  - disable_strategy
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required
  - sysctl_kernel_dmesg_restrict

- name: Comment out any occurrences of kernel.dmesg_restrict from config files
  replace:
    path: '{{ item.path }}'
    regexp: ^[\s]*kernel.dmesg_restrict
    replace: '#kernel.dmesg_restrict'
  loop: '{{ find_sysctl_d.files }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.5
  - NIST-800-53-SI-11(a)
  - NIST-800-53-SI-11(b)
  - disable_strategy
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required
  - sysctl_kernel_dmesg_restrict

- name: Ensure sysctl kernel.dmesg_restrict is set to 1
  sysctl:
    name: kernel.dmesg_restrict
    value: '1'
    sysctl_file: /etc/sysctl.conf
    state: present
    reload: true
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.5
  - NIST-800-53-SI-11(a)
  - NIST-800-53-SI-11(b)
  - disable_strategy
  - low_complexity
  - low_severity
  - medium_disruption
  - reboot_required
  - sysctl_kernel_dmesg_restrict

Group SELinux Group contains 1 group and 67 rules

[ref] SELinux is a feature of the Linux kernel which can be used to guard against misconfigured or compromised programs. SELinux enforces the idea that programs should be limited in what files they can access and what actions they can take.

The default SELinux policy, as configured on Red Hat Virtualization 4, has been sufficiently developed and debugged that it should be usable on almost any system with minimal configuration and a small amount of system administrator training. This policy prevents system services - including most of the common network-visible services such as mail servers, FTP servers, and DNS servers - from accessing files which those services have no valid reason to access. This action alone prevents a huge amount of possible damage from network attacks against services, from trojaned software, and so forth.

This guide recommends that SELinux be enabled using the default (targeted) policy on every Red Hat Virtualization 4 system, unless that system has unusual requirements which make a stronger policy appropriate.

Group SELinux - Booleans Group contains 61 rules

[ref] Enable or Disable runtime customization of SELinux system policies without having to reload or recompile the SELinux policy.

Rule Disable the abrt_anon_write SELinux Boolean [ref]

By default, the SELinux boolean abrt_anon_write is disabled. If this setting is enabled, it should be disabled. To disable the abrt_anon_write SELinux boolean, run the following command:

$ sudo setsebool -P abrt_anon_write off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_abrt_anon_write

References:

cui	3.7.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_abrt_anon_write='false'

    setsebool -P abrt_anon_write $var_abrt_anon_write

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.7.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_abrt_anon_write

- name: Disable the abrt_anon_write SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.7.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_abrt_anon_write
- name: XCCDF Value var_abrt_anon_write # promote to variable
  set_fact:
    var_abrt_anon_write: !!str false
  tags:
    - always

- name: Disable the abrt_anon_write SELinux Boolean - Set SELinux Boolean abrt_anon_write
    Accordingly
  seboolean:
    name: abrt_anon_write
    state: '{{ var_abrt_anon_write }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - NIST-800-171-3.7.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_abrt_anon_write

Rule Disable the abrt_handle_event SELinux Boolean [ref]

By default, the SELinux boolean abrt_handle_event is disabled. If this setting is enabled, it should be disabled. To disable the abrt_handle_event SELinux boolean, run the following command:

$ sudo setsebool -P abrt_handle_event off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_abrt_handle_event

References:

cui	3.7.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_abrt_handle_event='false'

    setsebool -P abrt_handle_event $var_abrt_handle_event

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.7.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_abrt_handle_event

- name: Disable the abrt_handle_event SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.7.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_abrt_handle_event
- name: XCCDF Value var_abrt_handle_event # promote to variable
  set_fact:
    var_abrt_handle_event: !!str false
  tags:
    - always

- name: Disable the abrt_handle_event SELinux Boolean - Set SELinux Boolean abrt_handle_event
    Accordingly
  seboolean:
    name: abrt_handle_event
    state: '{{ var_abrt_handle_event }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - NIST-800-171-3.7.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_abrt_handle_event

Rule Disable the abrt_upload_watch_anon_write SELinux Boolean [ref]

By default, the SELinux boolean abrt_upload_watch_anon_write is enabled. This setting should be disabled as it allows the Automatic Bug Report Tool (ABRT) to modify public files used for public file transfer services. To disable the abrt_upload_watch_anon_write SELinux boolean, run the following command:

$ sudo setsebool -P abrt_upload_watch_anon_write off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_abrt_upload_watch_anon_write

References:

cui	3.7.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_abrt_upload_watch_anon_write='true'

    setsebool -P abrt_upload_watch_anon_write $var_abrt_upload_watch_anon_write

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.7.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_abrt_upload_watch_anon_write

- name: Disable the abrt_upload_watch_anon_write SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.7.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_abrt_upload_watch_anon_write
- name: XCCDF Value var_abrt_upload_watch_anon_write # promote to variable
  set_fact:
    var_abrt_upload_watch_anon_write: !!str true
  tags:
    - always

- name: Disable the abrt_upload_watch_anon_write SELinux Boolean - Set SELinux Boolean
    abrt_upload_watch_anon_write Accordingly
  seboolean:
    name: abrt_upload_watch_anon_write
    state: '{{ var_abrt_upload_watch_anon_write }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - NIST-800-171-3.7.2
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_abrt_upload_watch_anon_write

Rule Enable the auditadm_exec_content SELinux Boolean [ref]

By default, the SELinux boolean auditadm_exec_content is enabled. If this setting is disabled, it should be enabled. To enable the auditadm_exec_content SELinux boolean, run the following command:

$ sudo setsebool -P auditadm_exec_content on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_auditadm_exec_content

References:

cui	80424-5
ism	0582, 0584, 05885, 0586, 0846, 0957

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_auditadm_exec_content='true'

    setsebool -P auditadm_exec_content $var_auditadm_exec_content

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-80424-5
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_auditadm_exec_content

- name: Enable the auditadm_exec_content SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-80424-5
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_auditadm_exec_content
- name: XCCDF Value var_auditadm_exec_content # promote to variable
  set_fact:
    var_auditadm_exec_content: !!str true
  tags:
    - always

- name: Enable the auditadm_exec_content SELinux Boolean - Set SELinux Boolean auditadm_exec_content
    Accordingly
  seboolean:
    name: auditadm_exec_content
    state: '{{ var_auditadm_exec_content }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - NIST-800-171-80424-5
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_auditadm_exec_content

Rule Disable the cron_can_relabel SELinux Boolean [ref]

By default, the SELinux boolean cron_can_relabel is disabled. If this setting is enabled, it should be disabled. To disable the cron_can_relabel SELinux boolean, run the following command:

$ sudo setsebool -P cron_can_relabel off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_cron_can_relabel

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_cron_can_relabel='false'

    setsebool -P cron_can_relabel $var_cron_can_relabel

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_cron_can_relabel

- name: Disable the cron_can_relabel SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_cron_can_relabel
- name: XCCDF Value var_cron_can_relabel # promote to variable
  set_fact:
    var_cron_can_relabel: !!str false
  tags:
    - always

- name: Disable the cron_can_relabel SELinux Boolean - Set SELinux Boolean cron_can_relabel
    Accordingly
  seboolean:
    name: cron_can_relabel
    state: '{{ var_cron_can_relabel }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_cron_can_relabel

Rule Disable the cron_system_cronjob_use_shares SELinux Boolean [ref]

By default, the SELinux boolean cron_system_cronjob_use_shares is disabled. If this setting is enabled, it should be disabled. To disable the cron_system_cronjob_use_shares SELinux boolean, run the following command:

$ sudo setsebool -P cron_system_cronjob_use_shares off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_cron_system_cronjob_use_shares

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_cron_system_cronjob_use_shares='false'

    setsebool -P cron_system_cronjob_use_shares $var_cron_system_cronjob_use_shares

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_cron_system_cronjob_use_shares

- name: Disable the cron_system_cronjob_use_shares SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_cron_system_cronjob_use_shares
- name: XCCDF Value var_cron_system_cronjob_use_shares # promote to variable
  set_fact:
    var_cron_system_cronjob_use_shares: !!str false
  tags:
    - always

- name: Disable the cron_system_cronjob_use_shares SELinux Boolean - Set SELinux Boolean
    cron_system_cronjob_use_shares Accordingly
  seboolean:
    name: cron_system_cronjob_use_shares
    state: '{{ var_cron_system_cronjob_use_shares }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_cron_system_cronjob_use_shares

Rule Enable the cron_userdomain_transition SELinux Boolean [ref]

By default, the SELinux boolean cron_userdomain_transition is enabled. This setting should be enabled as end user cron jobs run in their default associated user domain(s) instead of the general cronjob domain. To enable the cron_userdomain_transition SELinux boolean, run the following command:

$ sudo setsebool -P cron_userdomain_transition on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_cron_userdomain_transition

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_cron_userdomain_transition='true'

    setsebool -P cron_userdomain_transition $var_cron_userdomain_transition

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_cron_userdomain_transition

- name: Enable the cron_userdomain_transition SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_cron_userdomain_transition
- name: XCCDF Value var_cron_userdomain_transition # promote to variable
  set_fact:
    var_cron_userdomain_transition: !!str true
  tags:
    - always

- name: Enable the cron_userdomain_transition SELinux Boolean - Set SELinux Boolean
    cron_userdomain_transition Accordingly
  seboolean:
    name: cron_userdomain_transition
    state: '{{ var_cron_userdomain_transition }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_cron_userdomain_transition

Rule Disable the daemons_dump_core SELinux Boolean [ref]

By default, the SELinux boolean daemons_dump_core is disabled. If this setting is enabled, it should be disabled. To disable the daemons_dump_core SELinux boolean, run the following command:

$ sudo setsebool -P daemons_dump_core off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_daemons_dump_core

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_daemons_dump_core='false'

    setsebool -P daemons_dump_core $var_daemons_dump_core

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_daemons_dump_core

- name: Disable the daemons_dump_core SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_daemons_dump_core
- name: XCCDF Value var_daemons_dump_core # promote to variable
  set_fact:
    var_daemons_dump_core: !!str false
  tags:
    - always

- name: Disable the daemons_dump_core SELinux Boolean - Set SELinux Boolean daemons_dump_core
    Accordingly
  seboolean:
    name: daemons_dump_core
    state: '{{ var_daemons_dump_core }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_daemons_dump_core

Rule Disable the daemons_use_tcp_wrapper SELinux Boolean [ref]

By default, the SELinux boolean daemons_use_tcp_wrapper is disabled. If this setting is enabled, it should be disabled. To disable the daemons_use_tcp_wrapper SELinux boolean, run the following command:

$ sudo setsebool -P daemons_use_tcp_wrapper off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_daemons_use_tcp_wrapper

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_daemons_use_tcp_wrapper='false'

    setsebool -P daemons_use_tcp_wrapper $var_daemons_use_tcp_wrapper

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_daemons_use_tcp_wrapper

- name: Disable the daemons_use_tcp_wrapper SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_daemons_use_tcp_wrapper
- name: XCCDF Value var_daemons_use_tcp_wrapper # promote to variable
  set_fact:
    var_daemons_use_tcp_wrapper: !!str false
  tags:
    - always

- name: Disable the daemons_use_tcp_wrapper SELinux Boolean - Set SELinux Boolean
    daemons_use_tcp_wrapper Accordingly
  seboolean:
    name: daemons_use_tcp_wrapper
    state: '{{ var_daemons_use_tcp_wrapper }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_daemons_use_tcp_wrapper

Rule Disable the daemons_use_tty SELinux Boolean [ref]

By default, the SELinux boolean daemons_use_tty is disabled. If this setting is enabled, it should be disabled. To disable the daemons_use_tty SELinux boolean, run the following command:

$ sudo setsebool -P daemons_use_tty off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_daemons_use_tty

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_daemons_use_tty='false'

    setsebool -P daemons_use_tty $var_daemons_use_tty

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_daemons_use_tty

- name: Disable the daemons_use_tty SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_daemons_use_tty
- name: XCCDF Value var_daemons_use_tty # promote to variable
  set_fact:
    var_daemons_use_tty: !!str false
  tags:
    - always

- name: Disable the daemons_use_tty SELinux Boolean - Set SELinux Boolean daemons_use_tty
    Accordingly
  seboolean:
    name: daemons_use_tty
    state: '{{ var_daemons_use_tty }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_daemons_use_tty

Rule Configure the deny_execmem SELinux Boolean [ref]

By default, the SELinux boolean deny_execmem is disabled. This setting should be configured to false.
To set the deny_execmem SELinux boolean, run the following command:

$ sudo setsebool -P deny_execmem false

Warning: This rule doesn't come with a remediation, as enabling this SELinux boolean can cause applications to malfunction, for example Graphical login managers and Firefox.

Warning: Proper function and stability should be assessed before applying enabling the SELinux boolean in production systems.

Rationale:

Allowing user domain applications to map a memory region as both writable and executable makes them more susceptible to data execution attacks.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_deny_execmem

References:

anssi	R48

Rule Disable the deny_ptrace SELinux Boolean [ref]

By default, the SELinux boolean deny_ptrace is disabled. If this setting is enabled, it should be disabled. To disable the deny_ptrace SELinux boolean, run the following command:

$ sudo setsebool -P deny_ptrace off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_deny_ptrace

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_deny_ptrace='false'

    setsebool -P deny_ptrace $var_deny_ptrace

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_deny_ptrace

- name: Disable the deny_ptrace SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_deny_ptrace
- name: XCCDF Value var_deny_ptrace # promote to variable
  set_fact:
    var_deny_ptrace: !!str false
  tags:
    - always

- name: Disable the deny_ptrace SELinux Boolean - Set SELinux Boolean deny_ptrace
    Accordingly
  seboolean:
    name: deny_ptrace
    state: '{{ var_deny_ptrace }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_deny_ptrace

Rule Enable the domain_fd_use SELinux Boolean [ref]

By default, the SELinux boolean domain_fd_use is enabled. If this setting is disabled, it should be enabled. To enable the domain_fd_use SELinux boolean, run the following command:

$ sudo setsebool -P domain_fd_use on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_domain_fd_use

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_domain_fd_use='true'

    setsebool -P domain_fd_use $var_domain_fd_use

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_domain_fd_use

- name: Enable the domain_fd_use SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_domain_fd_use
- name: XCCDF Value var_domain_fd_use # promote to variable
  set_fact:
    var_domain_fd_use: !!str true
  tags:
    - always

- name: Enable the domain_fd_use SELinux Boolean - Set SELinux Boolean domain_fd_use
    Accordingly
  seboolean:
    name: domain_fd_use
    state: '{{ var_domain_fd_use }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_domain_fd_use

Rule Disable the domain_kernel_load_modules SELinux Boolean [ref]

By default, the SELinux boolean domain_kernel_load_modules is disabled. If this setting is enabled, it should be disabled. To disable the domain_kernel_load_modules SELinux boolean, run the following command:

$ sudo setsebool -P domain_kernel_load_modules off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_domain_kernel_load_modules

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_domain_kernel_load_modules='false'

    setsebool -P domain_kernel_load_modules $var_domain_kernel_load_modules

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_domain_kernel_load_modules

- name: Disable the domain_kernel_load_modules SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_domain_kernel_load_modules
- name: XCCDF Value var_domain_kernel_load_modules # promote to variable
  set_fact:
    var_domain_kernel_load_modules: !!str false
  tags:
    - always

- name: Disable the domain_kernel_load_modules SELinux Boolean - Set SELinux Boolean
    domain_kernel_load_modules Accordingly
  seboolean:
    name: domain_kernel_load_modules
    state: '{{ var_domain_kernel_load_modules }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_domain_kernel_load_modules

Rule Enable the fips_mode SELinux Boolean [ref]

By default, the SELinux boolean fips_mode is enabled. This allows all SELinux domains to execute in fips_mode. If this setting is disabled, it should be enabled. To enable the fips_mode SELinux boolean, run the following command:

$ sudo setsebool -P fips_mode on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_fips_mode

References:

cis-csc	13
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.13.11
isa-62443-2013	SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	SC-12(2), SC-12(3), IA-7, SC-13, CM-6(a), SC-12
nist-csf	PR.DS-5

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_fips_mode='true'

    setsebool -P fips_mode $var_fips_mode

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-7
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_fips_mode

- name: Enable the fips_mode SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-7
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_fips_mode
- name: XCCDF Value var_fips_mode # promote to variable
  set_fact:
    var_fips_mode: !!str true
  tags:
    - always

- name: Enable the fips_mode SELinux Boolean - Set SELinux Boolean fips_mode Accordingly
  seboolean:
    name: fips_mode
    state: '{{ var_fips_mode }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - NIST-800-171-3.13.11
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-7
  - NIST-800-53-SC-12
  - NIST-800-53-SC-12(2)
  - NIST-800-53-SC-12(3)
  - NIST-800-53-SC-13
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_fips_mode

Rule Disable the gpg_web_anon_write SELinux Boolean [ref]

By default, the SELinux boolean gpg_web_anon_write is disabled. If this setting is enabled, it should be disabled. To disable the gpg_web_anon_write SELinux boolean, run the following command:

$ sudo setsebool -P gpg_web_anon_write off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_gpg_web_anon_write

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_gpg_web_anon_write='false'

    setsebool -P gpg_web_anon_write $var_gpg_web_anon_write

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_gpg_web_anon_write

- name: Disable the gpg_web_anon_write SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_gpg_web_anon_write
- name: XCCDF Value var_gpg_web_anon_write # promote to variable
  set_fact:
    var_gpg_web_anon_write: !!str false
  tags:
    - always

- name: Disable the gpg_web_anon_write SELinux Boolean - Set SELinux Boolean gpg_web_anon_write
    Accordingly
  seboolean:
    name: gpg_web_anon_write
    state: '{{ var_gpg_web_anon_write }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_gpg_web_anon_write

Rule Disable the guest_exec_content SELinux Boolean [ref]

By default, the SELinux boolean guest_exec_content is enabled. This setting should be disabled as no guest accounts should be used. To disable the guest_exec_content SELinux boolean, run the following command:

$ sudo setsebool -P guest_exec_content off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_guest_exec_content

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_guest_exec_content='true'

    setsebool -P guest_exec_content $var_guest_exec_content

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_guest_exec_content

- name: Disable the guest_exec_content SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_guest_exec_content
- name: XCCDF Value var_guest_exec_content # promote to variable
  set_fact:
    var_guest_exec_content: !!str true
  tags:
    - always

- name: Disable the guest_exec_content SELinux Boolean - Set SELinux Boolean guest_exec_content
    Accordingly
  seboolean:
    name: guest_exec_content
    state: '{{ var_guest_exec_content }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_guest_exec_content

Rule Enable the kerberos_enabled SELinux Boolean [ref]

By default, the SELinux boolean kerberos_enabled is enabled. If this setting is disabled, it should be enabled to allow confined applications to run with Kerberos. To enable the kerberos_enabled SELinux boolean, run the following command:

$ sudo setsebool -P kerberos_enabled on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_kerberos_enabled

References:

ism	0418, 1055, 1402

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_kerberos_enabled='true'

    setsebool -P kerberos_enabled $var_kerberos_enabled

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_kerberos_enabled

- name: Enable the kerberos_enabled SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_kerberos_enabled
- name: XCCDF Value var_kerberos_enabled # promote to variable
  set_fact:
    var_kerberos_enabled: !!str true
  tags:
    - always

- name: Enable the kerberos_enabled SELinux Boolean - Set SELinux Boolean kerberos_enabled
    Accordingly
  seboolean:
    name: kerberos_enabled
    state: '{{ var_kerberos_enabled }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_kerberos_enabled

Rule Enable the logadm_exec_content SELinux Boolean [ref]

By default, the SELinux boolean logadm_exec_content is enabled. If this setting is disabled, it should be enabled. To enable the logadm_exec_content SELinux boolean, run the following command:

$ sudo setsebool -P logadm_exec_content on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_logadm_exec_content

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_logadm_exec_content='true'

    setsebool -P logadm_exec_content $var_logadm_exec_content

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_logadm_exec_content

- name: Enable the logadm_exec_content SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_logadm_exec_content
- name: XCCDF Value var_logadm_exec_content # promote to variable
  set_fact:
    var_logadm_exec_content: !!str true
  tags:
    - always

- name: Enable the logadm_exec_content SELinux Boolean - Set SELinux Boolean logadm_exec_content
    Accordingly
  seboolean:
    name: logadm_exec_content
    state: '{{ var_logadm_exec_content }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_logadm_exec_content

Rule Disable the logging_syslogd_can_sendmail SELinux Boolean [ref]

By default, the SELinux boolean logging_syslogd_can_sendmail is disabled. If this setting is enabled, it should be disabled. To disable the logging_syslogd_can_sendmail SELinux boolean, run the following command:

$ sudo setsebool -P logging_syslogd_can_sendmail off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_logging_syslogd_can_sendmail

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_logging_syslogd_can_sendmail='false'

    setsebool -P logging_syslogd_can_sendmail $var_logging_syslogd_can_sendmail

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_logging_syslogd_can_sendmail

- name: Disable the logging_syslogd_can_sendmail SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_logging_syslogd_can_sendmail
- name: XCCDF Value var_logging_syslogd_can_sendmail # promote to variable
  set_fact:
    var_logging_syslogd_can_sendmail: !!str false
  tags:
    - always

- name: Disable the logging_syslogd_can_sendmail SELinux Boolean - Set SELinux Boolean
    logging_syslogd_can_sendmail Accordingly
  seboolean:
    name: logging_syslogd_can_sendmail
    state: '{{ var_logging_syslogd_can_sendmail }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_logging_syslogd_can_sendmail

Rule Enable the logging_syslogd_use_tty SELinux Boolean [ref]

By default, the SELinux boolean logging_syslogd_use_tty is enabled. If this setting is disabled, it should be enabled as it allows syslog the ability to read/write to terminal. To enable the logging_syslogd_use_tty SELinux boolean, run the following command:

$ sudo setsebool -P logging_syslogd_use_tty on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_logging_syslogd_use_tty

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_logging_syslogd_use_tty='true'

    setsebool -P logging_syslogd_use_tty $var_logging_syslogd_use_tty

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_logging_syslogd_use_tty

- name: Enable the logging_syslogd_use_tty SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_logging_syslogd_use_tty
- name: XCCDF Value var_logging_syslogd_use_tty # promote to variable
  set_fact:
    var_logging_syslogd_use_tty: !!str true
  tags:
    - always

- name: Enable the logging_syslogd_use_tty SELinux Boolean - Set SELinux Boolean logging_syslogd_use_tty
    Accordingly
  seboolean:
    name: logging_syslogd_use_tty
    state: '{{ var_logging_syslogd_use_tty }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_logging_syslogd_use_tty

Rule Enable the login_console_enabled SELinux Boolean [ref]

By default, the SELinux boolean login_console_enabled is enabled. If this setting is disabled, it should be enabled as it allows login from /dev/console to a console session. To enable the login_console_enabled SELinux boolean, run the following command:

$ sudo setsebool -P login_console_enabled on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_login_console_enabled

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_login_console_enabled='true'

    setsebool -P login_console_enabled $var_login_console_enabled

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_login_console_enabled

- name: Enable the login_console_enabled SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_login_console_enabled
- name: XCCDF Value var_login_console_enabled # promote to variable
  set_fact:
    var_login_console_enabled: !!str true
  tags:
    - always

- name: Enable the login_console_enabled SELinux Boolean - Set SELinux Boolean login_console_enabled
    Accordingly
  seboolean:
    name: login_console_enabled
    state: '{{ var_login_console_enabled }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_login_console_enabled

Rule Disable the mmap_low_allowed SELinux Boolean [ref]

By default, the SELinux boolean mmap_low_allowed is disabled. If this setting is enabled, it should be disabled. To disable the mmap_low_allowed SELinux boolean, run the following command:

$ sudo setsebool -P mmap_low_allowed off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_mmap_low_allowed

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_mmap_low_allowed='false'

    setsebool -P mmap_low_allowed $var_mmap_low_allowed

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_mmap_low_allowed

- name: Disable the mmap_low_allowed SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_mmap_low_allowed
- name: XCCDF Value var_mmap_low_allowed # promote to variable
  set_fact:
    var_mmap_low_allowed: !!str false
  tags:
    - always

- name: Disable the mmap_low_allowed SELinux Boolean - Set SELinux Boolean mmap_low_allowed
    Accordingly
  seboolean:
    name: mmap_low_allowed
    state: '{{ var_mmap_low_allowed }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_mmap_low_allowed

Rule Disable the mock_enable_homedirs SELinux Boolean [ref]

By default, the SELinux boolean mock_enable_homedirs is disabled. If this setting is enabled, it should be disabled. To disable the mock_enable_homedirs SELinux boolean, run the following command:

$ sudo setsebool -P mock_enable_homedirs off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_mock_enable_homedirs

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_mock_enable_homedirs='false'

    setsebool -P mock_enable_homedirs $var_mock_enable_homedirs

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_mock_enable_homedirs

- name: Disable the mock_enable_homedirs SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_mock_enable_homedirs
- name: XCCDF Value var_mock_enable_homedirs # promote to variable
  set_fact:
    var_mock_enable_homedirs: !!str false
  tags:
    - always

- name: Disable the mock_enable_homedirs SELinux Boolean - Set SELinux Boolean mock_enable_homedirs
    Accordingly
  seboolean:
    name: mock_enable_homedirs
    state: '{{ var_mock_enable_homedirs }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_mock_enable_homedirs

Rule Enable the mount_anyfile SELinux Boolean [ref]

By default, the SELinux boolean mount_anyfile is enabled. If this setting is disabled, it should be enabled to allow any file or directory to be mounted. To enable the mount_anyfile SELinux boolean, run the following command:

$ sudo setsebool -P mount_anyfile on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_mount_anyfile

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_mount_anyfile='true'

    setsebool -P mount_anyfile $var_mount_anyfile

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_mount_anyfile

- name: Enable the mount_anyfile SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_mount_anyfile
- name: XCCDF Value var_mount_anyfile # promote to variable
  set_fact:
    var_mount_anyfile: !!str true
  tags:
    - always

- name: Enable the mount_anyfile SELinux Boolean - Set SELinux Boolean mount_anyfile
    Accordingly
  seboolean:
    name: mount_anyfile
    state: '{{ var_mount_anyfile }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_mount_anyfile

Rule Configure the polyinstantiation_enabled SELinux Boolean [ref]

By default, the SELinux boolean polyinstantiation_enabled is disabled. This setting should be configured to false.
To set the polyinstantiation_enabled SELinux boolean, run the following command:

$ sudo setsebool -P polyinstantiation_enabled false

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_polyinstantiation_enabled

References:

anssi	R55

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_polyinstantiation_enabled='false'

    setsebool -P polyinstantiation_enabled $var_polyinstantiation_enabled

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_polyinstantiation_enabled

- name: Configure the polyinstantiation_enabled SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_polyinstantiation_enabled
- name: XCCDF Value var_polyinstantiation_enabled # promote to variable
  set_fact:
    var_polyinstantiation_enabled: !!str false
  tags:
    - always

- name: Configure the polyinstantiation_enabled SELinux Boolean - Set SELinux Boolean
    polyinstantiation_enabled Accordingly
  seboolean:
    name: polyinstantiation_enabled
    state: '{{ var_polyinstantiation_enabled }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_polyinstantiation_enabled

Rule Enable the secadm_exec_content SELinux Boolean [ref]

By default, the SELinux boolean secadm_exec_content is enabled. If this setting is disabled, it should be enabled. To enable the secadm_exec_content SELinux boolean, run the following command:

$ sudo setsebool -P secadm_exec_content on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_secadm_exec_content

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_secadm_exec_content='true'

    setsebool -P secadm_exec_content $var_secadm_exec_content

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secadm_exec_content

- name: Enable the secadm_exec_content SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secadm_exec_content
- name: XCCDF Value var_secadm_exec_content # promote to variable
  set_fact:
    var_secadm_exec_content: !!str true
  tags:
    - always

- name: Enable the secadm_exec_content SELinux Boolean - Set SELinux Boolean secadm_exec_content
    Accordingly
  seboolean:
    name: secadm_exec_content
    state: '{{ var_secadm_exec_content }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secadm_exec_content

Rule Disable the secure_mode SELinux Boolean [ref]

By default, the SELinux boolean secure_mode is disabled. If this setting is enabled, it should be disabled. To disable the secure_mode SELinux boolean, run the following command:

$ sudo setsebool -P secure_mode off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_secure_mode

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_secure_mode='false'

    setsebool -P secure_mode $var_secure_mode

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secure_mode

- name: Disable the secure_mode SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secure_mode
- name: XCCDF Value var_secure_mode # promote to variable
  set_fact:
    var_secure_mode: !!str false
  tags:
    - always

- name: Disable the secure_mode SELinux Boolean - Set SELinux Boolean secure_mode
    Accordingly
  seboolean:
    name: secure_mode
    state: '{{ var_secure_mode }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secure_mode

Rule Configure the secure_mode_insmod SELinux Boolean [ref]

By default, the SELinux boolean secure_mode_insmod is disabled. This setting should be configured to false.
To set the secure_mode_insmod SELinux boolean, run the following command:

$ sudo setsebool -P secure_mode_insmod false

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_secure_mode_insmod

References:

anssi	R48

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_secure_mode_insmod='false'

    setsebool -P secure_mode_insmod $var_secure_mode_insmod

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secure_mode_insmod

- name: Configure the secure_mode_insmod SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secure_mode_insmod
- name: XCCDF Value var_secure_mode_insmod # promote to variable
  set_fact:
    var_secure_mode_insmod: !!str false
  tags:
    - always

- name: Configure the secure_mode_insmod SELinux Boolean - Set SELinux Boolean secure_mode_insmod
    Accordingly
  seboolean:
    name: secure_mode_insmod
    state: '{{ var_secure_mode_insmod }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secure_mode_insmod

Rule Disable the secure_mode_policyload SELinux Boolean [ref]

By default, the SELinux boolean secure_mode_policyload is disabled. If this setting is enabled, it should be disabled. To disable the secure_mode_policyload SELinux boolean, run the following command:

$ sudo setsebool -P secure_mode_policyload off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_secure_mode_policyload

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_secure_mode_policyload='false'

    setsebool -P secure_mode_policyload $var_secure_mode_policyload

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secure_mode_policyload

- name: Disable the secure_mode_policyload SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secure_mode_policyload
- name: XCCDF Value var_secure_mode_policyload # promote to variable
  set_fact:
    var_secure_mode_policyload: !!str false
  tags:
    - always

- name: Disable the secure_mode_policyload SELinux Boolean - Set SELinux Boolean secure_mode_policyload
    Accordingly
  seboolean:
    name: secure_mode_policyload
    state: '{{ var_secure_mode_policyload }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_secure_mode_policyload

Rule Configure the selinuxuser_direct_dri_enabled SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_direct_dri_enabled is enabled. If XWindows is not installed or used on the system, this setting should be disabled. Otherwise, enable it. To disable the selinuxuser_direct_dri_enabled SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_direct_dri_enabled off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_direct_dri_enabled

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_direct_dri_enabled='true'

    setsebool -P selinuxuser_direct_dri_enabled $var_selinuxuser_direct_dri_enabled

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_direct_dri_enabled

- name: Configure the selinuxuser_direct_dri_enabled SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_direct_dri_enabled
- name: XCCDF Value var_selinuxuser_direct_dri_enabled # promote to variable
  set_fact:
    var_selinuxuser_direct_dri_enabled: !!str true
  tags:
    - always

- name: Configure the selinuxuser_direct_dri_enabled SELinux Boolean - Set SELinux
    Boolean selinuxuser_direct_dri_enabled Accordingly
  seboolean:
    name: selinuxuser_direct_dri_enabled
    state: '{{ var_selinuxuser_direct_dri_enabled }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_direct_dri_enabled

Rule Disable the selinuxuser_execheap SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_execheap is disabled. When enabled this boolean is enabled it allows selinuxusers to execute code from the heap. If this setting is enabled, it should be disabled. To disable the selinuxuser_execheap SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_execheap off

Rationale:

Disabling code execution from the heap blocks buffer overflow attacks.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execheap

References:

hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
anssi	R48

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_execheap='false'

    setsebool -P selinuxuser_execheap $var_selinuxuser_execheap

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execheap

- name: Disable the selinuxuser_execheap SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execheap
- name: XCCDF Value var_selinuxuser_execheap # promote to variable
  set_fact:
    var_selinuxuser_execheap: !!str false
  tags:
    - always

- name: Disable the selinuxuser_execheap SELinux Boolean - Set SELinux Boolean selinuxuser_execheap
    Accordingly
  seboolean:
    name: selinuxuser_execheap
    state: '{{ var_selinuxuser_execheap }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execheap

Rule Enable the selinuxuser_execmod SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_execmod is enabled. If this setting is disabled, it should be enabled. To enable the selinuxuser_execmod SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_execmod on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execmod

References:

hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_execmod='true'

    setsebool -P selinuxuser_execmod $var_selinuxuser_execmod

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execmod

- name: Enable the selinuxuser_execmod SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execmod
- name: XCCDF Value var_selinuxuser_execmod # promote to variable
  set_fact:
    var_selinuxuser_execmod: !!str true
  tags:
    - always

- name: Enable the selinuxuser_execmod SELinux Boolean - Set SELinux Boolean selinuxuser_execmod
    Accordingly
  seboolean:
    name: selinuxuser_execmod
    state: '{{ var_selinuxuser_execmod }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execmod

Rule Disable the selinuxuser_execstack SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_execstack is enabled. This setting should be disabled as unconfined executables should not be able to make their stack executable. To disable the selinuxuser_execstack SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_execstack off

Rationale:

Disabling code execution from the stack blocks buffer overflow attacks.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execstack

References:

hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
anssi	R48

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_execstack='false'

    setsebool -P selinuxuser_execstack $var_selinuxuser_execstack

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execstack

- name: Disable the selinuxuser_execstack SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execstack
- name: XCCDF Value var_selinuxuser_execstack # promote to variable
  set_fact:
    var_selinuxuser_execstack: !!str false
  tags:
    - always

- name: Disable the selinuxuser_execstack SELinux Boolean - Set SELinux Boolean selinuxuser_execstack
    Accordingly
  seboolean:
    name: selinuxuser_execstack
    state: '{{ var_selinuxuser_execstack }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_execstack

Rule Disable the selinuxuser_mysql_connect_enabled SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_mysql_connect_enabled is disabled. If this setting is enabled, it should be disabled. To disable the selinuxuser_mysql_connect_enabled SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_mysql_connect_enabled off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_mysql_connect_enabled

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_mysql_connect_enabled='false'

    setsebool -P selinuxuser_mysql_connect_enabled $var_selinuxuser_mysql_connect_enabled

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_mysql_connect_enabled

- name: Disable the selinuxuser_mysql_connect_enabled SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_mysql_connect_enabled
- name: XCCDF Value var_selinuxuser_mysql_connect_enabled # promote to variable
  set_fact:
    var_selinuxuser_mysql_connect_enabled: !!str false
  tags:
    - always

- name: Disable the selinuxuser_mysql_connect_enabled SELinux Boolean - Set SELinux
    Boolean selinuxuser_mysql_connect_enabled Accordingly
  seboolean:
    name: selinuxuser_mysql_connect_enabled
    state: '{{ var_selinuxuser_mysql_connect_enabled }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_mysql_connect_enabled

Rule Enable the selinuxuser_ping SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_ping is enabled. If this setting is disabled, it should be enabled as it allows confined users to use ping and traceroute which is helpful for network troubleshooting. To enable the selinuxuser_ping SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_ping on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_ping

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_ping='true'

    setsebool -P selinuxuser_ping $var_selinuxuser_ping

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_ping

- name: Enable the selinuxuser_ping SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_ping
- name: XCCDF Value var_selinuxuser_ping # promote to variable
  set_fact:
    var_selinuxuser_ping: !!str true
  tags:
    - always

- name: Enable the selinuxuser_ping SELinux Boolean - Set SELinux Boolean selinuxuser_ping
    Accordingly
  seboolean:
    name: selinuxuser_ping
    state: '{{ var_selinuxuser_ping }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_ping

Rule Disable the selinuxuser_postgresql_connect_enabled SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_postgresql_connect_enabled is disabled. If this setting is enabled, it should be disabled. To disable the selinuxuser_postgresql_connect_enabled SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_postgresql_connect_enabled off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_postgresql_connect_enabled

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_postgresql_connect_enabled='false'

    setsebool -P selinuxuser_postgresql_connect_enabled $var_selinuxuser_postgresql_connect_enabled

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_postgresql_connect_enabled

- name: Disable the selinuxuser_postgresql_connect_enabled SELinux Boolean - Ensure
    libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_postgresql_connect_enabled
- name: XCCDF Value var_selinuxuser_postgresql_connect_enabled # promote to variable
  set_fact:
    var_selinuxuser_postgresql_connect_enabled: !!str false
  tags:
    - always

- name: Disable the selinuxuser_postgresql_connect_enabled SELinux Boolean - Set SELinux
    Boolean selinuxuser_postgresql_connect_enabled Accordingly
  seboolean:
    name: selinuxuser_postgresql_connect_enabled
    state: '{{ var_selinuxuser_postgresql_connect_enabled }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_postgresql_connect_enabled

Rule Disable the selinuxuser_rw_noexattrfile SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_rw_noexattrfile is enabled. This setting should be disabled as users should not be able to read/write files on filesystems that do not have extended attributes e.g. FAT, CDROM, FLOPPY, etc. To disable the selinuxuser_rw_noexattrfile SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_rw_noexattrfile off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_rw_noexattrfile

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_rw_noexattrfile='true'

    setsebool -P selinuxuser_rw_noexattrfile $var_selinuxuser_rw_noexattrfile

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_rw_noexattrfile

- name: Disable the selinuxuser_rw_noexattrfile SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_rw_noexattrfile
- name: XCCDF Value var_selinuxuser_rw_noexattrfile # promote to variable
  set_fact:
    var_selinuxuser_rw_noexattrfile: !!str true
  tags:
    - always

- name: Disable the selinuxuser_rw_noexattrfile SELinux Boolean - Set SELinux Boolean
    selinuxuser_rw_noexattrfile Accordingly
  seboolean:
    name: selinuxuser_rw_noexattrfile
    state: '{{ var_selinuxuser_rw_noexattrfile }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_rw_noexattrfile

Rule Disable the selinuxuser_share_music SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_share_music is disabled. If this setting is enabled, it should be disabled. To disable the selinuxuser_share_music SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_share_music off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_share_music

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_share_music='false'

    setsebool -P selinuxuser_share_music $var_selinuxuser_share_music

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_share_music

- name: Disable the selinuxuser_share_music SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_share_music
- name: XCCDF Value var_selinuxuser_share_music # promote to variable
  set_fact:
    var_selinuxuser_share_music: !!str false
  tags:
    - always

- name: Disable the selinuxuser_share_music SELinux Boolean - Set SELinux Boolean
    selinuxuser_share_music Accordingly
  seboolean:
    name: selinuxuser_share_music
    state: '{{ var_selinuxuser_share_music }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_share_music

Rule Disable the selinuxuser_tcp_server SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_tcp_server is disabled. If this setting is enabled, it should be disabled. To disable the selinuxuser_tcp_server SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_tcp_server off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_tcp_server

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_tcp_server='false'

    setsebool -P selinuxuser_tcp_server $var_selinuxuser_tcp_server

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_tcp_server

- name: Disable the selinuxuser_tcp_server SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_tcp_server
- name: XCCDF Value var_selinuxuser_tcp_server # promote to variable
  set_fact:
    var_selinuxuser_tcp_server: !!str false
  tags:
    - always

- name: Disable the selinuxuser_tcp_server SELinux Boolean - Set SELinux Boolean selinuxuser_tcp_server
    Accordingly
  seboolean:
    name: selinuxuser_tcp_server
    state: '{{ var_selinuxuser_tcp_server }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_tcp_server

Rule Disable the selinuxuser_udp_server SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_udp_server is disabled. If this setting is enabled, it should be disabled. To disable the selinuxuser_udp_server SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_udp_server off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_udp_server

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_udp_server='false'

    setsebool -P selinuxuser_udp_server $var_selinuxuser_udp_server

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_udp_server

- name: Disable the selinuxuser_udp_server SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_udp_server
- name: XCCDF Value var_selinuxuser_udp_server # promote to variable
  set_fact:
    var_selinuxuser_udp_server: !!str false
  tags:
    - always

- name: Disable the selinuxuser_udp_server SELinux Boolean - Set SELinux Boolean selinuxuser_udp_server
    Accordingly
  seboolean:
    name: selinuxuser_udp_server
    state: '{{ var_selinuxuser_udp_server }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_udp_server

Rule Disable the selinuxuser_use_ssh_chroot SELinux Boolean [ref]

By default, the SELinux boolean selinuxuser_use_ssh_chroot is disabled. If this setting is enabled, it should be disabled. To disable the selinuxuser_use_ssh_chroot SELinux boolean, run the following command:

$ sudo setsebool -P selinuxuser_use_ssh_chroot off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_selinuxuser_use_ssh_chroot

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_selinuxuser_use_ssh_chroot='false'

    setsebool -P selinuxuser_use_ssh_chroot $var_selinuxuser_use_ssh_chroot

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_use_ssh_chroot

- name: Disable the selinuxuser_use_ssh_chroot SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_use_ssh_chroot
- name: XCCDF Value var_selinuxuser_use_ssh_chroot # promote to variable
  set_fact:
    var_selinuxuser_use_ssh_chroot: !!str false
  tags:
    - always

- name: Disable the selinuxuser_use_ssh_chroot SELinux Boolean - Set SELinux Boolean
    selinuxuser_use_ssh_chroot Accordingly
  seboolean:
    name: selinuxuser_use_ssh_chroot
    state: '{{ var_selinuxuser_use_ssh_chroot }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_selinuxuser_use_ssh_chroot

Rule Disable the ssh_chroot_rw_homedirs SELinux Boolean [ref]

By default, the SELinux boolean ssh_chroot_rw_homedirs is disabled. If this setting is enabled, it should be disabled. To disable the ssh_chroot_rw_homedirs SELinux boolean, run the following command:

$ sudo setsebool -P ssh_chroot_rw_homedirs off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_ssh_chroot_rw_homedirs

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_ssh_chroot_rw_homedirs='false'

    setsebool -P ssh_chroot_rw_homedirs $var_ssh_chroot_rw_homedirs

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_ssh_chroot_rw_homedirs

- name: Disable the ssh_chroot_rw_homedirs SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_ssh_chroot_rw_homedirs
- name: XCCDF Value var_ssh_chroot_rw_homedirs # promote to variable
  set_fact:
    var_ssh_chroot_rw_homedirs: !!str false
  tags:
    - always

- name: Disable the ssh_chroot_rw_homedirs SELinux Boolean - Set SELinux Boolean ssh_chroot_rw_homedirs
    Accordingly
  seboolean:
    name: ssh_chroot_rw_homedirs
    state: '{{ var_ssh_chroot_rw_homedirs }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_ssh_chroot_rw_homedirs

Rule Disable the ssh_keysign SELinux Boolean [ref]

By default, the SELinux boolean ssh_keysign is disabled. If this setting is enabled, it should be disabled. To disable the ssh_keysign SELinux boolean, run the following command:

$ sudo setsebool -P ssh_keysign off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_ssh_keysign

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_ssh_keysign='false'

    setsebool -P ssh_keysign $var_ssh_keysign

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_ssh_keysign

- name: Disable the ssh_keysign SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_ssh_keysign
- name: XCCDF Value var_ssh_keysign # promote to variable
  set_fact:
    var_ssh_keysign: !!str false
  tags:
    - always

- name: Disable the ssh_keysign SELinux Boolean - Set SELinux Boolean ssh_keysign
    Accordingly
  seboolean:
    name: ssh_keysign
    state: '{{ var_ssh_keysign }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_ssh_keysign

Rule Disable the ssh_sysadm_login SELinux Boolean [ref]

By default, the SELinux boolean ssh_sysadm_login is disabled. If this setting is enabled, it should be disabled. To disable the ssh_sysadm_login SELinux boolean, run the following command:

$ sudo setsebool -P ssh_sysadm_login off

Rationale:

Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges. Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals who do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_ssh_sysadm_login

References:

disa	CCI-002165, CCI-002235
os-srg	SRG-OS-000324-GPOS-00125
anssi	R48

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_ssh_sysadm_login='false'

    setsebool -P ssh_sysadm_login $var_ssh_sysadm_login

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_ssh_sysadm_login

- name: Disable the ssh_sysadm_login SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_ssh_sysadm_login
- name: XCCDF Value var_ssh_sysadm_login # promote to variable
  set_fact:
    var_ssh_sysadm_login: !!str false
  tags:
    - always

- name: Disable the ssh_sysadm_login SELinux Boolean - Set SELinux Boolean ssh_sysadm_login
    Accordingly
  seboolean:
    name: ssh_sysadm_login
    state: '{{ var_ssh_sysadm_login }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_ssh_sysadm_login

Rule Enable the staff_exec_content SELinux Boolean [ref]

By default, the SELinux boolean staff_exec_content is enabled. If this setting is disabled, it should be enabled. To enable the staff_exec_content SELinux boolean, run the following command:

$ sudo setsebool -P staff_exec_content on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_staff_exec_content

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_staff_exec_content='true'

    setsebool -P staff_exec_content $var_staff_exec_content

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_staff_exec_content

- name: Enable the staff_exec_content SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_staff_exec_content
- name: XCCDF Value var_staff_exec_content # promote to variable
  set_fact:
    var_staff_exec_content: !!str true
  tags:
    - always

- name: Enable the staff_exec_content SELinux Boolean - Set SELinux Boolean staff_exec_content
    Accordingly
  seboolean:
    name: staff_exec_content
    state: '{{ var_staff_exec_content }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_staff_exec_content

Rule Enable the sysadm_exec_content SELinux Boolean [ref]

By default, the SELinux boolean sysadm_exec_content is enabled. If this setting is disabled, it should be enabled. To enable the sysadm_exec_content SELinux boolean, run the following command:

$ sudo setsebool -P sysadm_exec_content on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_sysadm_exec_content

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_sysadm_exec_content='true'

    setsebool -P sysadm_exec_content $var_sysadm_exec_content

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_sysadm_exec_content

- name: Enable the sysadm_exec_content SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_sysadm_exec_content
- name: XCCDF Value var_sysadm_exec_content # promote to variable
  set_fact:
    var_sysadm_exec_content: !!str true
  tags:
    - always

- name: Enable the sysadm_exec_content SELinux Boolean - Set SELinux Boolean sysadm_exec_content
    Accordingly
  seboolean:
    name: sysadm_exec_content
    state: '{{ var_sysadm_exec_content }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_sysadm_exec_content

Rule Enable the unconfined_login SELinux Boolean [ref]

By default, the SELinux boolean unconfined_login is enabled. If this setting is disabled, it should be enabled. To enable the unconfined_login SELinux boolean, run the following command:

$ sudo setsebool -P unconfined_login on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_unconfined_login

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_unconfined_login='true'

    setsebool -P unconfined_login $var_unconfined_login

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_unconfined_login

- name: Enable the unconfined_login SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_unconfined_login
- name: XCCDF Value var_unconfined_login # promote to variable
  set_fact:
    var_unconfined_login: !!str true
  tags:
    - always

- name: Enable the unconfined_login SELinux Boolean - Set SELinux Boolean unconfined_login
    Accordingly
  seboolean:
    name: unconfined_login
    state: '{{ var_unconfined_login }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_unconfined_login

Rule Disable the use_ecryptfs_home_dirs SELinux Boolean [ref]

By default, the SELinux boolean use_ecryptfs_home_dirs is disabled. If this setting is enabled, it should be disabled. To disable the use_ecryptfs_home_dirs SELinux boolean, run the following command:

$ sudo setsebool -P use_ecryptfs_home_dirs off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_use_ecryptfs_home_dirs

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_use_ecryptfs_home_dirs='false'

    setsebool -P use_ecryptfs_home_dirs $var_use_ecryptfs_home_dirs

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_use_ecryptfs_home_dirs

- name: Disable the use_ecryptfs_home_dirs SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_use_ecryptfs_home_dirs
- name: XCCDF Value var_use_ecryptfs_home_dirs # promote to variable
  set_fact:
    var_use_ecryptfs_home_dirs: !!str false
  tags:
    - always

- name: Disable the use_ecryptfs_home_dirs SELinux Boolean - Set SELinux Boolean use_ecryptfs_home_dirs
    Accordingly
  seboolean:
    name: use_ecryptfs_home_dirs
    state: '{{ var_use_ecryptfs_home_dirs }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_use_ecryptfs_home_dirs

Rule Enable the user_exec_content SELinux Boolean [ref]

By default, the SELinux boolean user_exec_content is enabled. If this setting is disabled, it should be enabled. To enable the user_exec_content SELinux boolean, run the following command:

$ sudo setsebool -P user_exec_content on

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_user_exec_content

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_user_exec_content='true'

    setsebool -P user_exec_content $var_user_exec_content

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_user_exec_content

- name: Enable the user_exec_content SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_user_exec_content
- name: XCCDF Value var_user_exec_content # promote to variable
  set_fact:
    var_user_exec_content: !!str true
  tags:
    - always

- name: Enable the user_exec_content SELinux Boolean - Set SELinux Boolean user_exec_content
    Accordingly
  seboolean:
    name: user_exec_content
    state: '{{ var_user_exec_content }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_user_exec_content

Rule Disable the xdm_bind_vnc_tcp_port SELinux Boolean [ref]

By default, the SELinux boolean xdm_bind_vnc_tcp_port is disabled. If this setting is enabled, it should be disabled. To disable the xdm_bind_vnc_tcp_port SELinux boolean, run the following command:

$ sudo setsebool -P xdm_bind_vnc_tcp_port off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xdm_bind_vnc_tcp_port

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xdm_bind_vnc_tcp_port='false'

    setsebool -P xdm_bind_vnc_tcp_port $var_xdm_bind_vnc_tcp_port

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_bind_vnc_tcp_port

- name: Disable the xdm_bind_vnc_tcp_port SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_bind_vnc_tcp_port
- name: XCCDF Value var_xdm_bind_vnc_tcp_port # promote to variable
  set_fact:
    var_xdm_bind_vnc_tcp_port: !!str false
  tags:
    - always

- name: Disable the xdm_bind_vnc_tcp_port SELinux Boolean - Set SELinux Boolean xdm_bind_vnc_tcp_port
    Accordingly
  seboolean:
    name: xdm_bind_vnc_tcp_port
    state: '{{ var_xdm_bind_vnc_tcp_port }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_bind_vnc_tcp_port

Rule Disable the xdm_exec_bootloader SELinux Boolean [ref]

By default, the SELinux boolean xdm_exec_bootloader is disabled. If this setting is enabled, it should be disabled. To disable the xdm_exec_bootloader SELinux boolean, run the following command:

$ sudo setsebool -P xdm_exec_bootloader off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xdm_exec_bootloader

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xdm_exec_bootloader='false'

    setsebool -P xdm_exec_bootloader $var_xdm_exec_bootloader

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_exec_bootloader

- name: Disable the xdm_exec_bootloader SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_exec_bootloader
- name: XCCDF Value var_xdm_exec_bootloader # promote to variable
  set_fact:
    var_xdm_exec_bootloader: !!str false
  tags:
    - always

- name: Disable the xdm_exec_bootloader SELinux Boolean - Set SELinux Boolean xdm_exec_bootloader
    Accordingly
  seboolean:
    name: xdm_exec_bootloader
    state: '{{ var_xdm_exec_bootloader }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_exec_bootloader

Rule Disable the xdm_sysadm_login SELinux Boolean [ref]

By default, the SELinux boolean xdm_sysadm_login is disabled. If this setting is enabled, it should be disabled. To disable the xdm_sysadm_login SELinux boolean, run the following command:

$ sudo setsebool -P xdm_sysadm_login off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xdm_sysadm_login

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xdm_sysadm_login='false'

    setsebool -P xdm_sysadm_login $var_xdm_sysadm_login

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_sysadm_login

- name: Disable the xdm_sysadm_login SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_sysadm_login
- name: XCCDF Value var_xdm_sysadm_login # promote to variable
  set_fact:
    var_xdm_sysadm_login: !!str false
  tags:
    - always

- name: Disable the xdm_sysadm_login SELinux Boolean - Set SELinux Boolean xdm_sysadm_login
    Accordingly
  seboolean:
    name: xdm_sysadm_login
    state: '{{ var_xdm_sysadm_login }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_sysadm_login

Rule Disable the xdm_write_home SELinux Boolean [ref]

By default, the SELinux boolean xdm_write_home is disabled. If this setting is enabled, it should be disabled. To disable the xdm_write_home SELinux boolean, run the following command:

$ sudo setsebool -P xdm_write_home off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xdm_write_home

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xdm_write_home='false'

    setsebool -P xdm_write_home $var_xdm_write_home

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_write_home

- name: Disable the xdm_write_home SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_write_home
- name: XCCDF Value var_xdm_write_home # promote to variable
  set_fact:
    var_xdm_write_home: !!str false
  tags:
    - always

- name: Disable the xdm_write_home SELinux Boolean - Set SELinux Boolean xdm_write_home
    Accordingly
  seboolean:
    name: xdm_write_home
    state: '{{ var_xdm_write_home }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xdm_write_home

Rule Disable the xguest_connect_network SELinux Boolean [ref]

By default, the SELinux boolean xguest_connect_network is enabled. This setting should be disabled as guest users should not be able to configure NetworkManager. To disable the xguest_connect_network SELinux boolean, run the following command:

$ sudo setsebool -P xguest_connect_network off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xguest_connect_network

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xguest_connect_network='true'

    setsebool -P xguest_connect_network $var_xguest_connect_network

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_connect_network

- name: Disable the xguest_connect_network SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_connect_network
- name: XCCDF Value var_xguest_connect_network # promote to variable
  set_fact:
    var_xguest_connect_network: !!str true
  tags:
    - always

- name: Disable the xguest_connect_network SELinux Boolean - Set SELinux Boolean xguest_connect_network
    Accordingly
  seboolean:
    name: xguest_connect_network
    state: '{{ var_xguest_connect_network }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_connect_network

Rule Disable the xguest_exec_content SELinux Boolean [ref]

By default, the SELinux boolean xguest_exec_content is enabled. This setting should be disabled as guest users should not be able to run executables. To disable the xguest_exec_content SELinux boolean, run the following command:

$ sudo setsebool -P xguest_exec_content off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xguest_exec_content

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xguest_exec_content='true'

    setsebool -P xguest_exec_content $var_xguest_exec_content

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_exec_content

- name: Disable the xguest_exec_content SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_exec_content
- name: XCCDF Value var_xguest_exec_content # promote to variable
  set_fact:
    var_xguest_exec_content: !!str true
  tags:
    - always

- name: Disable the xguest_exec_content SELinux Boolean - Set SELinux Boolean xguest_exec_content
    Accordingly
  seboolean:
    name: xguest_exec_content
    state: '{{ var_xguest_exec_content }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_exec_content

Rule Disable the xguest_mount_media SELinux Boolean [ref]

By default, the SELinux boolean xguest_mount_media is enabled. This setting should be disabled as guest users should not be able to mount any media. To disable the xguest_mount_media SELinux boolean, run the following command:

$ sudo setsebool -P xguest_mount_media off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xguest_mount_media

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xguest_mount_media='true'

    setsebool -P xguest_mount_media $var_xguest_mount_media

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_mount_media

- name: Disable the xguest_mount_media SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_mount_media
- name: XCCDF Value var_xguest_mount_media # promote to variable
  set_fact:
    var_xguest_mount_media: !!str true
  tags:
    - always

- name: Disable the xguest_mount_media SELinux Boolean - Set SELinux Boolean xguest_mount_media
    Accordingly
  seboolean:
    name: xguest_mount_media
    state: '{{ var_xguest_mount_media }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_mount_media

Rule Disable the xguest_use_bluetooth SELinux Boolean [ref]

By default, the SELinux boolean xguest_use_bluetooth is enabled. This setting should be disabled as guests users should not be able to access or use bluetooth. To disable the xguest_use_bluetooth SELinux boolean, run the following command:

$ sudo setsebool -P xguest_use_bluetooth off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xguest_use_bluetooth

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xguest_use_bluetooth='true'

    setsebool -P xguest_use_bluetooth $var_xguest_use_bluetooth

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_use_bluetooth

- name: Disable the xguest_use_bluetooth SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_use_bluetooth
- name: XCCDF Value var_xguest_use_bluetooth # promote to variable
  set_fact:
    var_xguest_use_bluetooth: !!str true
  tags:
    - always

- name: Disable the xguest_use_bluetooth SELinux Boolean - Set SELinux Boolean xguest_use_bluetooth
    Accordingly
  seboolean:
    name: xguest_use_bluetooth
    state: '{{ var_xguest_use_bluetooth }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xguest_use_bluetooth

Rule Disable the xserver_clients_write_xshm SELinux Boolean [ref]

By default, the SELinux boolean xserver_clients_write_xshm is disabled. If this setting is enabled, it should be disabled. To disable the xserver_clients_write_xshm SELinux boolean, run the following command:

$ sudo setsebool -P xserver_clients_write_xshm off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xserver_clients_write_xshm

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xserver_clients_write_xshm='false'

    setsebool -P xserver_clients_write_xshm $var_xserver_clients_write_xshm

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xserver_clients_write_xshm

- name: Disable the xserver_clients_write_xshm SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xserver_clients_write_xshm
- name: XCCDF Value var_xserver_clients_write_xshm # promote to variable
  set_fact:
    var_xserver_clients_write_xshm: !!str false
  tags:
    - always

- name: Disable the xserver_clients_write_xshm SELinux Boolean - Set SELinux Boolean
    xserver_clients_write_xshm Accordingly
  seboolean:
    name: xserver_clients_write_xshm
    state: '{{ var_xserver_clients_write_xshm }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xserver_clients_write_xshm

Rule Disable the xserver_execmem SELinux Boolean [ref]

By default, the SELinux boolean xserver_execmem is disabled. If this setting is enabled, it should be disabled. To disable the xserver_execmem SELinux boolean, run the following command:

$ sudo setsebool -P xserver_execmem off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xserver_execmem

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xserver_execmem='false'

    setsebool -P xserver_execmem $var_xserver_execmem

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xserver_execmem

- name: Disable the xserver_execmem SELinux Boolean - Ensure libsemanage-python Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xserver_execmem
- name: XCCDF Value var_xserver_execmem # promote to variable
  set_fact:
    var_xserver_execmem: !!str false
  tags:
    - always

- name: Disable the xserver_execmem SELinux Boolean - Set SELinux Boolean xserver_execmem
    Accordingly
  seboolean:
    name: xserver_execmem
    state: '{{ var_xserver_execmem }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xserver_execmem

Rule Disable the xserver_object_manager SELinux Boolean [ref]

By default, the SELinux boolean xserver_object_manager is disabled. If this setting is enabled, it should be disabled. To disable the xserver_object_manager SELinux boolean, run the following command:

$ sudo setsebool -P xserver_object_manager off

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sebool_xserver_object_manager

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "libsemanage-python" ; then
    yum install -y "libsemanage-python"
fi


if selinuxenabled || [[ "$OSCAP_BOOTC_BUILD" == "YES" ]] ; then

    var_xserver_object_manager='false'

    setsebool -P xserver_object_manager $var_xserver_object_manager

else
    echo "Skipping remediation, SELinux is disabled";
    false
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xserver_object_manager

- name: Disable the xserver_object_manager SELinux Boolean - Ensure libsemanage-python
    Installed
  package:
    name: libsemanage-python
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xserver_object_manager
- name: XCCDF Value var_xserver_object_manager # promote to variable
  set_fact:
    var_xserver_object_manager: !!str false
  tags:
    - always

- name: Disable the xserver_object_manager SELinux Boolean - Set SELinux Boolean xserver_object_manager
    Accordingly
  seboolean:
    name: xserver_object_manager
    state: '{{ var_xserver_object_manager }}'
    persistent: true
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.selinux.status == 'enabled'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - sebool_xserver_object_manager

Rule Ensure SELinux Not Disabled in /etc/default/grub [ref]

SELinux can be disabled at boot time by an argument in /etc/default/grub. Remove any instances of selinux=0 from the kernel arguments in that file to prevent SELinux from being disabled at boot.

Rationale:

Disabling a major host protection feature, such as SELinux, at boot time prevents it from confining system services at boot time. Further, it increases the chances that it will remain off during system operation.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_grub2_enable_selinux

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9
cobit5	APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01
cui	3.1.2, 3.7.2
disa	CCI-000022, CCI-000032
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
isa-62443-2009	4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	AC-3, AC-3(3)(a)
nist-csf	DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4
pcidss4	1.2.6, 1.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && { rpm --quiet -q grub2-common; }; then

sed -i --follow-symlinks "s/selinux=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*
sed -i --follow-symlinks "s/enforcing=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - grub2_enable_selinux
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure SELinux Not Disabled in /etc/default/grub - Find /etc/grub.d/ files
  ansible.builtin.find:
    paths:
    - /etc/grub.d/
    follow: true
  register: result_grub_d
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - grub2_enable_selinux
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure SELinux Not Disabled in /etc/default/grub - Ensure SELinux Not Disabled
    in /etc/grub.d/ files
  ansible.builtin.replace:
    dest: '{{ item.path }}'
    regexp: (selinux|enforcing)=0
  with_items:
  - '{{ result_grub_d.files }}'
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - grub2_enable_selinux
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure SELinux Not Disabled in /etc/default/grub - Check if /etc/grub2.cfg
    exists
  ansible.builtin.stat:
    path: /etc/grub2.cfg
  register: result_grub2_cfg_present
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - grub2_enable_selinux
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure SELinux Not Disabled in /etc/default/grub - Check if /etc/default/grub
    exists
  ansible.builtin.stat:
    path: /etc/default/grub
  register: result_default_grub_present
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - grub2_enable_selinux
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure SELinux Not Disabled in /etc/default/grub - Ensure SELinux Not Disabled
    in /etc/grub2.cfg
  ansible.builtin.replace:
    dest: /etc/grub2.cfg
    regexp: (selinux|enforcing)=0
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  - result_grub2_cfg_present.stat.exists
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - grub2_enable_selinux
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure SELinux Not Disabled in /etc/default/grub - Ensure SELinux Not Disabled
    in /etc/default/grub
  ansible.builtin.replace:
    dest: /etc/default/grub
    regexp: (selinux|enforcing)=0
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  - result_default_grub_present.stat.exists
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - grub2_enable_selinux
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure No Device Files are Unlabeled by SELinux [ref]

Device files, which are used for communication with important system resources, should be labeled with proper SELinux types. If any device files carry the SELinux type device_t or unlabeled_t, report the bug so that policy can be corrected. Supply information about what the device is and what programs use it.

To check for incorrectly labeled device files, run following commands:

$ sudo find /dev -context *:device_t:* \( -type c -o -type b \) -printf "%p %Z\n"

$ sudo find /dev -context *:unlabeled_t:* \( -type c -o -type b \) -printf "%p %Z\n"

It should produce no output in a well-configured system.

Warning: Automatic remediation of this control is not available. The remediation can be achieved by amending SELinux policy.

Rationale:

If a device file carries the SELinux type device_t or unlabeled_t, then SELinux cannot properly restrict access to the device file.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_selinux_all_devicefiles_labeled

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 5, 6, 7, 8, 9
cobit5	APO01.06, APO11.04, BAI01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, MEA02.01
cui	3.1.2, 3.1.5, 3.7.2
disa	CCI-000366
isa-62443-2009	4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 5.2, SR 6.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), CM-6(a), AC-3(3)(a), AC-6
nist-csf	DE.CM-1, DE.CM-7, PR.AC-4, PR.DS-5, PR.IP-1, PR.IP-3, PR.PT-1, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227

Rule Ensure No Daemons are Unconfined by SELinux [ref]

Daemons for which the SELinux policy does not contain rules will inherit the context of the parent process. Because daemons are launched during startup and descend from the init process, they inherit the unconfined_service_t context.

To check for unconfined daemons, run the following command:

$ sudo ps -eZ | grep "unconfined_service_t"

It should produce no output in a well-configured system.

Warning: Automatic remediation of this control is not available. Remediation can be achieved by amending SELinux policy or stopping the unconfined daemons as outlined above.

Rationale:

Daemons which run with the unconfined_service_t context may cause AVC denials, or allow privileges that the daemon does not require.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_selinux_confinement_of_daemons

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9
cobit5	APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, MEA02.01
cui	3.1.2, 3.1.5, 3.7.2
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
isa-62443-2009	4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 5.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-7(a), CM-7(b), CM-6(a), AC-3(3)(a), AC-6
nist-csf	PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, PR.PT-3
pcidss4	1.2.6, 1.2

Rule Configure SELinux Policy [ref]

The SELinux targeted policy is appropriate for general-purpose desktops and servers, as well as systems in many other roles. To configure the system to use this policy, add or correct the following line in /etc/selinux/config:

SELINUXTYPE=targeted

Other policies, such as mls, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

Rationale:

Setting the SELinux policy to targeted or a more specialized policy ensures the system will confine processes that are likely to be targeted for exploitation, such as network or system services.

Note: During the development or debugging of SELinux modules, it is common to temporarily place non-production systems in permissive mode. In such temporary cases, SELinux policies should be developed, and once work is completed, the system should be reconfigured to targeted.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_selinux_policytype

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9
cobit5	APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01
cui	3.1.2, 3.7.2
disa	CCI-002696
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
isa-62443-2009	4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5
nist	AC-3, AC-3(3)(a), AU-9, SC-7(21)
nist-csf	DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000445-GPOS-00199
app-srg-ctr	SRG-APP-000233-CTR-000585
anssi	R46, R64
bsi	APP.4.4.A4, SYS.1.6.A3, SYS.1.6.A18, SYS.1.6.A21
pcidss4	1.2.6, 1.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

var_selinux_policy_name='targeted'


if [ -e "/etc/selinux/config" ] ; then
    
    LC_ALL=C sed -i "/^SELINUXTYPE=/Id" "/etc/selinux/config"
else
    touch "/etc/selinux/config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/selinux/config"

cp "/etc/selinux/config" "/etc/selinux/config.bak"
# Insert at the end of the file
printf '%s\n' "SELINUXTYPE=$var_selinux_policy_name" >> "/etc/selinux/config"
# Clean up after ourselves.
rm "/etc/selinux/config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - NIST-800-53-AU-9
  - NIST-800-53-SC-7(21)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
  - selinux_policytype
- name: XCCDF Value var_selinux_policy_name # promote to variable
  set_fact:
    var_selinux_policy_name: !!str targeted
  tags:
    - always

- name: Configure SELinux Policy
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/selinux/config
      create: true
      regexp: (?i)^SELINUXTYPE=
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/selinux/config
    lineinfile:
      path: /etc/selinux/config
      create: true
      regexp: (?i)^SELINUXTYPE=
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/selinux/config
    lineinfile:
      path: /etc/selinux/config
      create: true
      regexp: (?i)^SELINUXTYPE=
      line: SELINUXTYPE={{ var_selinux_policy_name }}
      state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - NIST-800-53-AU-9
  - NIST-800-53-SC-7(21)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
  - selinux_policytype

Rule Ensure SELinux State is Enforcing [ref]

The SELinux state should be set to enforcing at system boot time. In the file /etc/selinux/config, add or correct the following line to configure the system to boot into enforcing mode:

SELINUX=enforcing

Rationale:

Setting the SELinux state to enforcing ensures SELinux is able to confine potentially compromised processes to the security policy, which is designed to prevent them from causing damage to the system or further elevating their privileges.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_selinux_state

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9
cobit5	APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01
cui	3.1.2, 3.7.2
disa	CCI-002696, CCI-001084
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
isa-62443-2009	4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5
nist	AC-3, AC-3(3)(a), AU-9, SC-7(21)
nist-csf	DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000445-GPOS-00199, SRG-OS-000134-GPOS-00068
anssi	R37, R79
bsi	APP.4.4.A4, SYS.1.6.A3, SYS.1.6.A18, SYS.1.6.A21
pcidss4	1.2.6, 1.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

var_selinux_state='enforcing'


if [ -e "/etc/selinux/config" ] ; then
    
    LC_ALL=C sed -i "/^SELINUX=/Id" "/etc/selinux/config"
else
    touch "/etc/selinux/config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/selinux/config"

cp "/etc/selinux/config" "/etc/selinux/config.bak"
# Insert at the end of the file
printf '%s\n' "SELINUX=$var_selinux_state" >> "/etc/selinux/config"
# Clean up after ourselves.
rm "/etc/selinux/config.bak"

fixfiles onboot
fixfiles -f relabel

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - NIST-800-53-AU-9
  - NIST-800-53-SC-7(21)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy
  - selinux_state
- name: XCCDF Value var_selinux_state # promote to variable
  set_fact:
    var_selinux_state: !!str enforcing
  tags:
    - always

- name: Ensure SELinux State is Enforcing
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/selinux/config
      create: true
      regexp: (?i)^SELINUX=
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/selinux/config
    lineinfile:
      path: /etc/selinux/config
      create: true
      regexp: (?i)^SELINUX=
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/selinux/config
    lineinfile:
      path: /etc/selinux/config
      create: true
      regexp: (?i)^SELINUX=
      line: SELINUX={{ var_selinux_state }}
      state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.2
  - NIST-800-171-3.7.2
  - NIST-800-53-AC-3
  - NIST-800-53-AC-3(3)(a)
  - NIST-800-53-AU-9
  - NIST-800-53-SC-7(21)
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.6
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy
  - selinux_state

Rule Map System Users To The Appropriate SELinux Role [ref]

Configure the operating system to prevent non-privileged users from executing privileged functions to include disabling, circumventing, or altering implemented security safeguards/countermeasures. All administrators must be mapped to the sysadm_u or staff_u users with the appropriate domains (sysadm_t and staff_t).

$ sudo semanage login -m -s sysadm_u USER

$ sudo semanage login -m -s staff_u USER

All authorized non-administrative users must be mapped to the user_u role or the appropriate domain (user_t).

$ sudo semanage login -m -s user_u USER

Rationale:

Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges.

Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals who do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_selinux_user_login_roles

References:

disa	CCI-002165, CCI-002235
os-srg	SRG-OS-000324-GPOS-00125

Group Services Group contains 26 groups and 55 rules

[ref] The best protection against vulnerable software is running less software. This section describes how to review the software which Red Hat Virtualization 4 installs on a system and disable software which is not needed. It then enumerates the software packages installed on a default Red Hat Virtualization 4 system and provides guidance about which ones can be safely disabled.

Red Hat Virtualization 4 provides a convenient minimal install option that essentially installs the bare necessities for a functional system. When building Red Hat Virtualization 4 systems, it is highly recommended to select the minimal packages and then build up the system from there.

Group Base Services Group contains 1 rule

[ref] This section addresses the base services that are installed on a Red Hat Virtualization 4 default installation which are not covered in other sections. Some of these services listen on the network and should be treated with particular discretion. Other services are local system utilities that may or may not be extraneous. In general, system services should be disabled if not required.

Rule Disable KDump Kernel Crash Analyzer (kdump) [ref]

The kdump service provides a kernel crash dump analyzer. It uses the kexec system call to boot a secondary kernel ("capture" kernel) following a system crash, which can load information from the crashed kernel for analysis. The kdump service can be disabled with the following command:

$ sudo systemctl mask --now kdump.service

Rationale:

Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps consume a considerable amount of disk space and may result in denial of service by exhausting the available space on the target file system partition. Unless the system is used for kernel development or testing, there is little need to run the kdump service.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_kdump_disabled

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
disa	CCI-000366
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
ospp	FMT_SMF_EXT.1.1
os-srg	SRG-OS-000269-GPOS-00103, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'kdump.service'
"$SYSTEMCTL_EXEC" disable 'kdump.service'
"$SYSTEMCTL_EXEC" mask 'kdump.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files kdump.socket; then
    "$SYSTEMCTL_EXEC" stop 'kdump.socket'
    "$SYSTEMCTL_EXEC" mask 'kdump.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'kdump.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
masked = ["kdump"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_kdump_disabled

- name: Disable KDump Kernel Crash Analyzer (kdump) - Collect systemd Services Present
    in the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_kdump_disabled

- name: Disable KDump Kernel Crash Analyzer (kdump) - Ensure kdump.service is Masked
  ansible.builtin.systemd:
    name: kdump.service
    state: stopped
    enabled: false
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - service_exists.stdout_lines is search("kdump.service", multiline=True)
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_kdump_disabled

- name: Unit Socket Exists - kdump.socket
  ansible.builtin.command: systemctl -q list-unit-files kdump.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_kdump_disabled

- name: Disable KDump Kernel Crash Analyzer (kdump) - Disable Socket kdump
  ansible.builtin.systemd:
    name: kdump.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - socket_file_exists.stdout_lines is search("kdump.socket", multiline=True)
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_kdump_disabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include disable_kdump

class disable_kdump {
  service {'kdump':
    enable => false,
    ensure => 'stopped',
  }
}

Group Cron and At Daemons Group contains 1 group and 3 rules

[ref] The cron and at services are used to allow commands to be executed at a later time. The cron service is required by almost all systems to perform necessary maintenance tasks, while at may or may not be required on a given system. Both daemons should be configured defensively.

Group Restrict at and cron to Authorized Users if Necessary Group contains 2 rules

[ref] The /etc/cron.allow and /etc/at.allow files contain lists of users who are allowed to use cron and at to delay execution of processes. If these files exist and if the corresponding files /etc/cron.deny and /etc/at.deny do not exist, then only users listed in the relevant allow files can run the crontab and at commands to submit jobs to be run at scheduled intervals. On many systems, only the system administrator needs the ability to schedule jobs. Note that even if a given user is not listed in cron.allow, cron jobs can still be run as that user. The cron.allow file controls only administrative access to the crontab command for scheduling and modifying cron jobs.

To restrict at and cron to only authorized users:

Remove the cron.deny file:
```
$ sudo rm /etc/cron.deny
```
Edit /etc/cron.allow, adding one line for each user allowed to use the crontab command to create cron jobs.
Remove the at.deny file:
```
$ sudo rm /etc/at.deny
```
Edit /etc/at.allow, adding one line for each user allowed to use the at command to create at jobs.

Rule Verify Group Who Owns /etc/cron.allow file [ref]

If /etc/cron.allow exists, it must be group-owned by root. To properly set the group owner of /etc/cron.allow, run the command:

$ sudo chgrp root /etc/cron.allow

Rationale:

If the owner of the cron.allow file is not set to root, the possibility exists for an unauthorized user to view or edit sensitive information.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_groupowner_cron_allow

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
disa	CCI-000366
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.DS-5
os-srg	SRG-OS-000480-GPOS-00227
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

chgrp 0 /etc/cron.allow

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Test for existence /etc/cron.allow
  stat:
    path: /etc/cron.allow
  register: file_exists
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure group owner 0 on /etc/cron.allow
  file:
    path: /etc/cron.allow
    group: '0'
  when:
  - '"kernel" in ansible_facts.packages'
  - file_exists.stat is defined and file_exists.stat.exists
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Verify User Who Owns /etc/cron.allow file [ref]

If /etc/cron.allow exists, it must be owned by root. To properly set the owner of /etc/cron.allow, run the command:

$ sudo chown root /etc/cron.allow

Rationale:

If the owner of the cron.allow file is not set to root, the possibility exists for an unauthorized user to view or edit sensitive information.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_owner_cron_allow

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
disa	CCI-000366
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.DS-5
os-srg	SRG-OS-000480-GPOS-00227
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

chown 0 /etc/cron.allow

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_owner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Test for existence /etc/cron.allow
  stat:
    path: /etc/cron.allow
  register: file_exists
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_owner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure owner 0 on /etc/cron.allow
  file:
    path: /etc/cron.allow
    owner: '0'
  when:
  - '"kernel" in ansible_facts.packages'
  - file_exists.stat is defined and file_exists.stat.exists
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_owner_cron_allow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Enable cron Service [ref]

The crond service is used to execute commands at preconfigured times. It is required by almost all systems to perform necessary maintenance tasks, such as notifying root of system activity. The crond service can be enabled with the following command:

$ sudo systemctl enable crond.service

Rationale:

Due to its usage for maintenance and security-supporting tasks, enabling the cron daemon is essential.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_crond_enabled

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-6(a)
nist-csf	PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'crond.service'
"$SYSTEMCTL_EXEC" start 'crond.service'
"$SYSTEMCTL_EXEC" enable 'crond.service'

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
enabled = ["crond"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_crond_enabled

- name: Enable cron Service - Enable service crond
  block:

  - name: Gather the package facts
    package_facts:
      manager: auto

  - name: Enable cron Service - Enable Service crond
    ansible.builtin.systemd:
      name: crond
      enabled: true
      state: started
      masked: false
    when:
    - '"cronie" in ansible_facts.packages'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_crond_enabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include enable_crond

class enable_crond {
  service {'crond':
    enable => true,
    ensure => 'running',
  }
}

Group FTP Server Group contains 1 group and 1 rule

[ref] FTP is a common method for allowing remote access to files. Like telnet, the FTP protocol is unencrypted, which means that passwords and other data transmitted during the session can be captured and that the session is vulnerable to hijacking. Therefore, running the FTP server software is not recommended.

However, there are some FTP server configurations which may be appropriate for some environments, particularly those which allow only read-only anonymous access as a means of downloading data available to the public.

Group Disable vsftpd if Possible Group contains 1 rule

[ref] To minimize attack surface, disable vsftpd if at all possible.

Rule Uninstall vsftpd Package [ref]

The vsftpd package can be removed with the following command:

 $ sudo yum erase vsftpd

Rationale:

Removing the vsftpd package decreases the risk of its accidental activation.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_package_vsftpd_removed

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
disa	CCI-000366, CCI-000197, CCI-000381
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), IA-5(1).1(v), CM-7, CM-7.1(ii)
nist-csf	PR.IP-1, PR.PT-3
os-srg	SRG-OS-000074-GPOS-00042, SRG-OS-000095-GPOS-00049, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


# CAUTION: This remediation script will remove vsftpd
#	   from the system, and may remove any packages
#	   that depend on vsftpd. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "vsftpd" ; then
yum remove -y "vsftpd"
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Ensure vsftpd is removed
  package:
    name: vsftpd
    state: absent
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-CM-7.1(ii)
  - NIST-800-53-IA-5(1)(c)
  - NIST-800-53-IA-5(1).1(v)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - package_vsftpd_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=vsftpd

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_vsftpd

class remove_vsftpd {
  package { 'vsftpd':
    ensure => 'purged',
  }
}

Group LDAP Group contains 1 group and 1 rule

[ref] LDAP is a popular directory service, that is, a standardized way of looking up information from a central database. Red Hat Virtualization 4 includes software that enables a system to act as both an LDAP client and server.

Group Configure OpenLDAP Clients Group contains 1 rule

[ref] This section provides information on which security settings are important to configure in OpenLDAP clients by manually editing the appropriate configuration files. Red Hat Virtualization 4 provides an automated configuration tool called authconfig and a graphical wrapper for authconfig called system-config-authentication. However, these tools do not provide as much control over configuration as manual editing of configuration files. The authconfig tools do not allow you to specify locations of SSL certificate files, which is useful when trying to use SSL cleanly across several protocols. Installation and configuration of OpenLDAP on Red Hat Virtualization 4 is available at

Warning: Before configuring any system to be an LDAP client, ensure that a working LDAP server is present on the network.

Rule Configure LDAP Client to Use TLS For All Transactions [ref]

This check verifies cryptography has been implemented to protect the integrity of remote LDAP authentication sessions.

To determine if LDAP is being used for authentication, use the following command:

$ sudo grep -i useldapauth /etc/sysconfig/authconfig

If USELDAPAUTH=yes, then LDAP is being used. To check if LDAP is configured to use TLS, use the following command:

$ sudo grep -i ssl /etc/pam_ldap.conf

Rationale:

Without cryptographic integrity protections, information can be altered by unauthorized users without detection. The ssl directive specifies whether to use TLS or not. If not specified it will default to no. It should be set to start_tls rather than doing LDAP over SSL.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_ldap_client_start_tls

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
disa	CCI-001453
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	AC-17(a), AC-17(2), CM-6(a), SC-12(a), SC-12(b)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000250-GPOS-00093

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q nss-pam-ldapd; then

# Use LDAP for authentication
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^USELDAPAUTH")

# shellcheck disable=SC2059
printf -v formatted_output "%s=%s" "$stripped_key" "yes"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^USELDAPAUTH\\>" "/etc/sysconfig/authconfig"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^USELDAPAUTH\\>.*/$escaped_formatted_output/gi" "/etc/sysconfig/authconfig"
else
    if [[ -s "/etc/sysconfig/authconfig" ]] && [[ -n "$(tail -c 1 -- "/etc/sysconfig/authconfig" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/sysconfig/authconfig"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/sysconfig/authconfig"
fi

# Configure client to use TLS for all authentications
# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^ssl")

# shellcheck disable=SC2059
printf -v formatted_output "%s %s" "$stripped_key" "start_tls"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^ssl\\>" "/etc/nslcd.conf"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^ssl\\>.*/$escaped_formatted_output/gi" "/etc/nslcd.conf"
else
    if [[ -s "/etc/nslcd.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/nslcd.conf" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/nslcd.conf"
    fi
    printf '%s\n' "$formatted_output" >> "/etc/nslcd.conf"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Group NFS and RPC Group contains 3 groups and 4 rules

[ref] The Network File System is a popular distributed filesystem for the Unix environment, and is very widely deployed. This section discusses the circumstances under which it is possible to disable NFS and its dependencies, and then details steps which should be taken to secure NFS's configuration. This section is relevant to systems operating as NFS clients, as well as to those operating as NFS servers.

Group Configure NFS Clients Group contains 1 group and 3 rules

[ref] The steps in this section are appropriate for systems which operate as NFS clients.

Group Mount Remote Filesystems with Restrictive Options Group contains 3 rules

[ref] Edit the file /etc/fstab. For each filesystem whose type (column 3) is nfs or nfs4, add the text ,nodev,nosuid to the list of mount options in column 4. If appropriate, also add ,noexec.

See the section titled "Restrict Partition Mount Options" for a description of the effects of these options. In general, execution of files mounted via NFS should be considered risky because of the possibility that an adversary could intercept the request and substitute a malicious file. Allowing setuid files to be executed from remote servers is particularly risky, both for this reason and because it requires the clients to extend root-level trust to the NFS server.

Rule Mount Remote Filesystems with nodev [ref]

Add the nodev option to the fourth column of /etc/fstab for the line which controls mounting of any NFS mounts.

Rationale:

Legitimate device files should only exist in the /dev directory. NFS mounts should not present device files to users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_mount_option_nodev_remote_filesystems

References:

cis-csc	11, 13, 14, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
iso27001-2013	A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2
nist	CM-6(a), MP-2
nist-csf	PR.IP-1, PR.PT-2, PR.PT-3
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

vfstype_points=()
readarray -t vfstype_points < <(grep -E "[[:space:]]nfs[4]?[[:space:]]" /etc/fstab | awk '{print $2}')

for vfstype_point in "${vfstype_points[@]}"
do
    mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" ${vfstype_point//\\/\\\\})"

    # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
    if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
        # runtime opts without some automatic kernel/userspace-added defaults
        previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                    | sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
        [ "$previous_mount_opts" ] && previous_mount_opts+=","
        # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
        # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
        fs_type="nfs4"
        if [  "$fs_type" == "iso9660" ] ; then
            previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
        fi
        echo " ${vfstype_point//\\/\\\\} nfs4 defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
    # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
    elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nodev"; then
        previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
        sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MP-2
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - mount_option_nodev_remote_filesystems
  - no_reboot_needed

- name: Get nfs and nfs4 mount points, that don't have nodev
  command: findmnt --fstab --types nfs,nfs4 -O nonodev -n -P
  register: points_register
  check_mode: false
  changed_when: false
  failed_when: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MP-2
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - mount_option_nodev_remote_filesystems
  - no_reboot_needed

- name: Add nodev to nfs and nfs4 mount points
  mount:
    path: '{{ item | regex_search(''TARGET="([^"]+)"'',''\1'') | first }}'
    src: '{{ item | regex_search(''SOURCE="([^"]+)"'',''\1'') | first }}'
    fstype: '{{ item | regex_search(''FSTYPE="([^"]+)"'',''\1'') | first }}'
    state: present
    opts: '{{ item | regex_search(''OPTIONS="([^"]+)"'',''\1'') | first }},nodev'
  when:
  - '"kernel" in ansible_facts.packages'
  - (points_register.stdout | length > 0) and '\\x09' not in item
  with_items: '{{ points_register.stdout_lines }}'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MP-2
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - mount_option_nodev_remote_filesystems
  - no_reboot_needed

Rule Mount Remote Filesystems with noexec [ref]

Add the noexec option to the fourth column of /etc/fstab for the line which controls mounting of any NFS mounts.

Rationale:

The noexec mount option causes the system not to execute binary files. This option must be used for mounting any file system not containing approved binary files as they may be incompatible. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_mount_option_noexec_remote_filesystems

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
disa	CCI-000366
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	AC-6, AC-6(8), AC-6(10), CM-6(a)
nist-csf	PR.AC-4, PR.DS-5
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

vfstype_points=()
readarray -t vfstype_points < <(grep -E "[[:space:]]nfs[4]?[[:space:]]" /etc/fstab | awk '{print $2}')

for vfstype_point in "${vfstype_points[@]}"
do
    mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" ${vfstype_point//\\/\\\\})"

    # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
    if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
        # runtime opts without some automatic kernel/userspace-added defaults
        previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                    | sed -E "s/(rw|defaults|seclabel|noexec)(,|$)//g;s/,$//")
        [ "$previous_mount_opts" ] && previous_mount_opts+=","
        # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
        # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
        fs_type="nfs4"
        if [  "$fs_type" == "iso9660" ] ; then
            previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
        fi
        echo " ${vfstype_point//\\/\\\\} nfs4 defaults,${previous_mount_opts}noexec 0 0" >> /etc/fstab
    # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
    elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "noexec"; then
        previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
        sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,noexec|" /etc/fstab
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(10)
  - NIST-800-53-AC-6(8)
  - NIST-800-53-CM-6(a)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - mount_option_noexec_remote_filesystems
  - no_reboot_needed

- name: Get nfs and nfs4 mount points, that don't have noexec
  command: findmnt --fstab --types nfs,nfs4 -O nonoexec -n -P
  register: points_register
  check_mode: false
  changed_when: false
  failed_when: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(10)
  - NIST-800-53-AC-6(8)
  - NIST-800-53-CM-6(a)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - mount_option_noexec_remote_filesystems
  - no_reboot_needed

- name: Add noexec to nfs and nfs4 mount points
  mount:
    path: '{{ item | regex_search(''TARGET="([^"]+)"'',''\1'') | first }}'
    src: '{{ item | regex_search(''SOURCE="([^"]+)"'',''\1'') | first }}'
    fstype: '{{ item | regex_search(''FSTYPE="([^"]+)"'',''\1'') | first }}'
    state: present
    opts: '{{ item | regex_search(''OPTIONS="([^"]+)"'',''\1'') | first }},noexec'
  when:
  - '"kernel" in ansible_facts.packages'
  - (points_register.stdout | length > 0) and '\\x09' not in item
  with_items: '{{ points_register.stdout_lines }}'
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(10)
  - NIST-800-53-AC-6(8)
  - NIST-800-53-CM-6(a)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - mount_option_noexec_remote_filesystems
  - no_reboot_needed

Rule Mount Remote Filesystems with nosuid [ref]

Add the nosuid option to the fourth column of /etc/fstab for the line which controls mounting of any NFS mounts.

Rationale:

NFS mounts should not present suid binaries to users. Only vendor-supplied suid executables should be installed to their default location on the local filesystem.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_mount_option_nosuid_remote_filesystems

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
disa	CCI-000366
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	AC-6, AC-6(1), CM6(a)
nist-csf	PR.AC-4, PR.DS-5
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

vfstype_points=()
readarray -t vfstype_points < <(grep -E "[[:space:]]nfs[4]?[[:space:]]" /etc/fstab | awk '{print $2}')

for vfstype_point in "${vfstype_points[@]}"
do
    mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" ${vfstype_point//\\/\\\\})"

    # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
    if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
        # runtime opts without some automatic kernel/userspace-added defaults
        previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                    | sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
        [ "$previous_mount_opts" ] && previous_mount_opts+=","
        # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
        # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
        fs_type="nfs4"
        if [  "$fs_type" == "iso9660" ] ; then
            previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
        fi
        echo " ${vfstype_point//\\/\\\\} nfs4 defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
    # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
    elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nosuid"; then
        previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
        sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM6(a)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - mount_option_nosuid_remote_filesystems
  - no_reboot_needed

- name: Get nfs and nfs4 mount points, that don't have nosuid
  command: findmnt --fstab --types nfs,nfs4 -O nonosuid -n -P
  register: points_register
  check_mode: false
  changed_when: false
  failed_when: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM6(a)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - mount_option_nosuid_remote_filesystems
  - no_reboot_needed

- name: Add nosuid to nfs and nfs4 mount points
  mount:
    path: '{{ item | regex_search(''TARGET="([^"]+)"'',''\1'') | first }}'
    src: '{{ item | regex_search(''SOURCE="([^"]+)"'',''\1'') | first }}'
    fstype: '{{ item | regex_search(''FSTYPE="([^"]+)"'',''\1'') | first }}'
    state: present
    opts: '{{ item | regex_search(''OPTIONS="([^"]+)"'',''\1'') | first }},nosuid'
  when:
  - '"kernel" in ansible_facts.packages'
  - (points_register.stdout | length > 0) and '\\x09' not in item
  with_items: '{{ points_register.stdout_lines }}'
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM6(a)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - mount_option_nosuid_remote_filesystems
  - no_reboot_needed

Group Configure NFS Servers Group contains 1 rule

[ref] The steps in this section are appropriate for systems which operate as NFS servers.

Rule Use Kerberos Security on All Exports [ref]

Using Kerberos on all exported mounts prevents a malicious client or user from impersonating a system user. To cryptography authenticate users to the NFS server, add sec=krb5:krb5i:krb5p to each export in /etc/exports.

Rationale:

When an NFS server is configured to use AUTH_SYS a selected userid and groupid are used to handle requests from the remote user. The userid and groupid could mistakenly or maliciously be set incorrectly. The AUTH_GSS method of authentication uses certificates on the server and client systems to more securely authenticate the remote mount request.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_use_kerberos_security_all_exports

References:

cis-csc	1, 12, 14, 15, 16, 18, 3, 5
cobit5	DSS05.04, DSS05.10, DSS06.10
disa	CCI-000366
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.6.1.2, A.9.1.2, A.9.2.1, A.9.2.3, A.9.2.4, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nist	CM-7(a), CM-7(b), CM-6(a), IA-2, IA-2(8), IA-2(9), AC-17(a)
nist-csf	PR.AC-4, PR.AC-7
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure


nfs_exports=()
readarray -t nfs_exports < <(grep -E "^/.*[[:space:]]+ .*\(.*\)[[:space:]]*$" /etc/exports | awk '{print $2}')

for nfs_export in "${nfs_exports[@]}"
do
    correct_export=""
    if [ "$(grep -c "sec=" <<<"$nfs_export")" -eq 0 ]; then
        correct_export="$(echo $nfs_export|sed  -e 's/).*$/,sec=krb5\:krb5i\:krb5p)/')"
    else
        correct_export="$(echo $nfs_export|sed  -e 's/sec=[^\,\)]*/sec=krb5\:krb5i\:krb5p/')"
    fi
    sed -i "s|$nfs_export|$correct_export|g" /etc/exports
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Drop any security clause for every export
  replace:
    path: /etc/exports
    regexp: ^(/.*\w+.*\(.*),sec=[^,]*(.*\)\w*$)
    replace: \1\2
  tags:
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-2
  - NIST-800-53-IA-2(8)
  - NIST-800-53-IA-2(9)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - use_kerberos_security_all_exports

- name: Add kerberos security when no security is defined for an export
  replace:
    path: /etc/exports
    regexp: ^(/.*\w+.*\(.*)(\)\w*$)
    replace: \1,sec=krb5:krb5i:krb5p\2
  tags:
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-2
  - NIST-800-53-IA-2(8)
  - NIST-800-53-IA-2(9)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - use_kerberos_security_all_exports

Group Network Time Protocol Group contains 4 rules

[ref] The Network Time Protocol is used to manage the system clock over a network. Computer clocks are not very accurate, so time will drift unpredictably on unmanaged systems. Central time protocols can be used both to ensure that time is consistent among a network of systems, and that their time is consistent with the outside world.

If every system on a network reliably reports the same time, then it is much easier to correlate log messages in case of an attack. In addition, a number of cryptographic protocols (such as Kerberos) use timestamps to prevent certain types of attacks. If your network does not have synchronized time, these protocols may be unreliable or even unusable.

Depending on the specifics of the network, global time accuracy may be just as important as local synchronization, or not very important at all. If your network is connected to the Internet, using a public timeserver (or one provided by your enterprise) provides globally accurate timestamps which may be essential in investigating or responding to an attack which originated outside of your network.

A typical network setup involves a small number of internal systems operating as NTP servers, and the remainder obtaining time information from those internal servers.

There is a choice between the daemons ntpd and chronyd, which are available from the repositories in the ntp and chrony packages respectively.

The default chronyd daemon can work well when external time references are only intermittently accesible, can perform well even when the network is congested for longer periods of time, can usually synchronize the clock faster and with better time accuracy, and quickly adapts to sudden changes in the rate of the clock, for example, due to changes in the temperature of the crystal oscillator. Chronyd should be considered for all systems which are frequently suspended or otherwise intermittently disconnected and reconnected to a network. Mobile and virtual systems for example.

The ntpd NTP daemon fully supports NTP protocol version 4 (RFC 5905), including broadcast, multicast, manycast clients and servers, and the orphan mode. It also supports extra authentication schemes based on public-key cryptography (RFC 5906). The NTP daemon (ntpd) should be considered for systems which are normally kept permanently on. Systems which are required to use broadcast or multicast IP, or to perform authentication of packets with the Autokey protocol, should consider using ntpd.

Refer to https://docs.fedoraproject.org/en-US/fedora/latest/system-administrators-guide/servers/Configuring_NTP_Using_the_chrony_Suite/ for more detailed comparison of features of chronyd and ntpd daemon features respectively, and for further guidance how to choose between the two NTP daemons.

The upstream manual pages at https://chrony-project.org/documentation.html for chronyd and http://www.ntp.org for ntpd provide additional information on the capabilities and configuration of each of the NTP daemons.

Rule Enable the NTP Daemon [ref]

Run the following command to determine the current status of the chronyd service:

$ sudo systemctl is-active chronyd

If the service is running, it should return the following:

active

Note: The chronyd daemon is enabled by default.

Run the following command to determine the current status of the ntpd service:

$ sudo systemctl is-active ntpd

If the service is running, it should return the following:

active

Note: The ntpd daemon is not enabled by default. Though as mentioned in the previous sections in certain environments the ntpd daemon might be preferred to be used rather than the chronyd one. Refer to: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/ch-configuring_ntp_using_the_chrony_suite for guidance which NTP daemon to choose depending on the environment used.

Rationale:

Enabling some of chronyd or ntpd services ensures that the NTP daemon will be running and that the system will synchronize its time to any servers specified. This is important whether the system is configured to be a client (and synchronize only its own clock) or it is also acting as an NTP server to other systems. Synchronizing time is essential for authentication services such as Kerberos, but it is also important for maintaining accurate logs and auditing possible security breaches.

The chronyd and ntpd NTP daemons offer all of the functionality of ntpdate, which is now deprecated.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_chronyd_or_ntpd_enabled

References:

cis-csc	1, 14, 15, 16, 3, 5, 6
cobit5	APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01
cui	3.3.7
disa	CCI-000160
isa-62443-2009	4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9
ism	0988, 1405
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1
nist	CM-6(a), AU-8(1)(a), AU-12(1)
nist-csf	PR.PT-1
pcidss	Req-10.4.1
app-srg-ctr	SRG-APP-000116-CTR-000235
anssi	R71
pcidss4	10.6.1, 10.6

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if rpm --quiet -q "chrony" ; then
    if ! /usr/sbin/pidof ntpd ; then
        /usr/bin/systemctl enable "chronyd"
        /usr/bin/systemctl start "chronyd"
        # The service may not be running because it has been started and failed,
        # so let's reset the state so OVAL checks pass.
        # Service should be 'inactive', not 'failed' after reboot though.
        if /usr/bin/systemctl --failed | grep -q "chronyd"; then
            /usr/bin/systemctl reset-failed "chronyd"
        fi
    fi
elif rpm --quiet -q "ntp" ; then
    /usr/bin/systemctl enable "ntpd"
    /usr/bin/systemctl start "ntpd"
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    if /usr/bin/systemctl --failed | grep -q "ntpd"; then
        /usr/bin/systemctl reset-failed "ntpd"
    fi
else
    if ! rpm -q --quiet "chrony" ; then
        yum install -y "chrony"
    fi
    /usr/bin/systemctl enable "chronyd"
    /usr/bin/systemctl start "chronyd"
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    if /usr/bin/systemctl --failed | grep -q "chronyd"; then
        /usr/bin/systemctl reset-failed "chronyd"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.3.7
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.1
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_chronyd_or_ntpd_enabled

- name: Gather the package facts
  ansible.builtin.package_facts:
    manager: auto
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.3.7
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.1
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_chronyd_or_ntpd_enabled

- name: Start ntpd service if ntp installed
  systemd:
    name: ntpd
    enabled: 'yes'
    state: started
    masked: 'no'
  when:
  - '"kernel" in ansible_facts.packages'
  - '''ntp'' in ansible_facts.packages'
  tags:
  - NIST-800-171-3.3.7
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.1
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_chronyd_or_ntpd_enabled

- name: Start chronyd service if chrony or chronyd installed
  systemd:
    name: chronyd
    enabled: 'yes'
    state: started
    masked: 'no'
  when:
  - '"kernel" in ansible_facts.packages'
  - ('chrony' in ansible_facts.packages) or ('chronyd' in ansible_facts.packages)
  tags:
  - NIST-800-171-3.3.7
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(a)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.1
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_chronyd_or_ntpd_enabled

Rule Configure Time Service Maxpoll Interval [ref]

The maxpoll should be configured to 10 in /etc/ntp.conf or /etc/chrony.conf (or /etc/chrony.d/) to continuously poll time servers. To configure maxpoll in /etc/ntp.conf or /etc/chrony.conf (or /etc/chrony.d/) add the following after each server, pool or peer entry:

maxpoll 10

to server directives. If using chrony, any pool directives should be configured too.

Rationale:

Inaccurate time stamps make it more difficult to correlate events and can lead to an inaccurate analysis. Determining the correct time a particular event occurred on a system is critical when conducting forensic analysis and investigating system events. Sources outside the configured acceptable allowance (drift) may be inaccurate. Synchronizing internal information system clocks provides uniformity of time stamps for information systems with multiple system clocks and systems connected over a network. Organizations should consider endpoints that may not have regular access to the authoritative time server (e.g., mobile, teleworking, and tactical endpoints).

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_chronyd_or_ntpd_set_maxpoll

References:

cis-csc	1, 14, 15, 16, 3, 5, 6
cobit5	APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01
disa	CCI-001890, CCI-004926, CCI-004923
isa-62443-2009	4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1
nist	CM-6(a), AU-8(1)(b), AU-12(1)
nist-csf	PR.PT-1
os-srg	SRG-OS-000355-GPOS-00143, SRG-OS-000356-GPOS-00144, SRG-OS-000359-GPOS-00146

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && { ( rpm --quiet -q chrony || rpm --quiet -q ntp ); }; then

var_time_service_set_maxpoll='10'




pof="/usr/sbin/pidof"


CONFIG_FILES="/etc/ntp.conf"
$pof ntpd || {
    CHRONY_D_PATH=/etc/chrony.d/
    mapfile -t CONFIG_FILES < <(find ${CHRONY_D_PATH}.* -type f -name '*.conf')
    CONFIG_FILES+=(/etc/chrony.conf)
}

# get list of ntp files

for config_file in "${CONFIG_FILES[@]}" ; do
    # Set maxpoll values to var_time_service_set_maxpoll
    sed -i "s/^\(\(server\|pool\|peer\).*maxpoll\) [0-9,-][0-9]*\(.*\)$/\1 $var_time_service_set_maxpoll \3/" "$config_file"
done

for config_file in "${CONFIG_FILES[@]}" ; do
    # Add maxpoll to server, pool or peer entries without maxpoll
    grep "^\(server\|pool\|peer\)" "$config_file" | grep -v maxpoll | while read -r line ; do
        sed -i "s/$line/& maxpoll $var_time_service_set_maxpoll/" "$config_file"
    done
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_time_service_set_maxpoll # promote to variable
  set_fact:
    var_time_service_set_maxpoll: !!str 10
  tags:
    - always

- name: Configure Time Service Maxpoll Interval - Check That /etc/ntp.conf Exist
  ansible.builtin.stat:
    path: /etc/ntp.conf
  register: ntp_conf_exist_result
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Time Service Maxpoll Interval - Update the maxpoll Values in /etc/ntp.conf
  ansible.builtin.replace:
    path: /etc/ntp.conf
    regexp: ^(server.*maxpoll)[ ]+[0-9]+(.*)$
    replace: \1 {{ var_time_service_set_maxpoll }}\2
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  - ntp_conf_exist_result.stat.exists
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Time Service Maxpoll Interval - Set the maxpoll Values in /etc/ntp.conf
  ansible.builtin.replace:
    path: /etc/ntp.conf
    regexp: (^server\s+((?!maxpoll).)*)$
    replace: \1 maxpoll {{ var_time_service_set_maxpoll }}\n
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  - ntp_conf_exist_result.stat.exists
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Time Service Maxpoll Interval - Check That /etc/chrony.conf Exist
  ansible.builtin.stat:
    path: /etc/chrony.conf
  register: chrony_conf_exist_result
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Time Service Maxpoll Interval - Update the maxpoll Values in /etc/chrony.conf
  ansible.builtin.replace:
    path: /etc/chrony.conf
    regexp: ^((?:server|pool|peer).*maxpoll)[ ]+[0-9]+(.*)$
    replace: \1 {{ var_time_service_set_maxpoll }}\2
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  - chrony_conf_exist_result.stat.exists
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Time Service Maxpoll Interval - Set the maxpoll Values in /etc/chrony.conf
  ansible.builtin.replace:
    path: /etc/chrony.conf
    regexp: (^(?:server|pool|peer)\s+((?!maxpoll).)*)$
    replace: \1 maxpoll {{ var_time_service_set_maxpoll }}\n
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  - chrony_conf_exist_result.stat.exists
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Time Service Maxpoll Interval - Get Conf Files from /etc/chrony.d/
  ansible.builtin.find:
    path: /etc/chrony.d/
    patterns: '*.conf'
    file_type: file
  register: chrony_d_conf_files
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Time Service Maxpoll Interval - Update the maxpoll Values in /etc/chrony.d/
  ansible.builtin.replace:
    path: '{{ item.path }}'
    regexp: ^((?:server|pool|peer).*maxpoll)[ ]+[0-9,-]+(.*)$
    replace: \1 {{ var_time_service_set_maxpoll }}\2
  loop: '{{ chrony_d_conf_files.files }}'
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  - chrony_d_conf_files.matched
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure Time Service Maxpoll Interval - Set the maxpoll Values in /etc/chrony.d/
  ansible.builtin.replace:
    path: '{{ item.path }}'
    regexp: (^(?:server|pool|peer)\s+((?!maxpoll).)*)$
    replace: \1 maxpoll {{ var_time_service_set_maxpoll }}\n
  loop: '{{ chrony_d_conf_files.files }}'
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  - chrony_d_conf_files.matched
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(b)
  - NIST-800-53-CM-6(a)
  - chronyd_or_ntpd_set_maxpoll
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Specify Additional Remote NTP Servers [ref]

Depending on specific functional requirements of a concrete production environment, the Red Hat Virtualization 4 system can be configured to utilize the services of the chronyd NTP daemon (the default), or services of the ntpd NTP daemon. Refer to https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/ch-configuring_ntp_using_the_chrony_suite for more detailed comparison of the features of both of the choices, and for further guidance how to choose between the two NTP daemons.
Additional NTP servers can be specified for time synchronization. To do so, perform the following:

if the system is configured to use the chronyd as the NTP daemon (the default), edit the file /etc/chrony.conf as follows,
if the system is configured to use the ntpd as the NTP daemon, edit the file /etc/ntp.conf as documented below.

Add additional lines of the following form, substituting the IP address or hostname of a remote NTP server for ntpserver:

server ntpserver

Rationale:

Specifying additional NTP servers increases the availability of accurate time data, in the event that one of the specified servers becomes unavailable. This is typical for a system acting as an NTP server for other systems.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_chronyd_or_ntpd_specify_multiple_servers

References:

cis-csc	1, 14, 15, 16, 3, 5, 6
cobit5	APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01
isa-62443-2009	4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9
ism	0988, 1405
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1
nist	CM-6(a), AU-8(1)(a), AU-8(2), AU-12(1)
nist-csf	PR.PT-1
pcidss	Req-10.4.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && { ( rpm --quiet -q chrony || rpm --quiet -q ntp ); }; then

var_multiple_time_servers='0.rhel.pool.ntp.org,1.rhel.pool.ntp.org,2.rhel.pool.ntp.org,3.rhel.pool.ntp.org'


config_file="/etc/ntp.conf"
/usr/sbin/pidof ntpd || config_file="/etc/chrony.conf"

if ! [ "$(grep -c '^server' "$config_file")" -gt 1 ] ; then
  if ! grep -q '#[[:space:]]*server' "$config_file" ; then
    for server in $(echo "$var_multiple_time_servers" | tr ',' '\n') ; do
      printf '\nserver %s' "$server" >> "$config_file"
    done
  else
    sed -i 's/#[ \t]*server/server/g' "$config_file"
  fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(a)
  - NIST-800-53-AU-8(2)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.3
  - chronyd_or_ntpd_specify_multiple_servers
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value var_multiple_time_servers # promote to variable
  set_fact:
    var_multiple_time_servers: !!str 0.rhel.pool.ntp.org,1.rhel.pool.ntp.org,2.rhel.pool.ntp.org,3.rhel.pool.ntp.org
  tags:
    - always

- name: Detect if chrony configuration file is present
  find:
    path: /etc
    patterns: chrony.conf
  register: chrony_server_config
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(a)
  - NIST-800-53-AU-8(2)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.3
  - chronyd_or_ntpd_specify_multiple_servers
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Configure multiple time servers in chrony config
  lineinfile:
    path: /etc/chrony.conf
    line: server {{ item }}
    state: present
    create: true
  loop: '{{ var_multiple_time_servers.split(",") }}'
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  - chrony_server_config.matched == 1
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(a)
  - NIST-800-53-AU-8(2)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.3
  - chronyd_or_ntpd_specify_multiple_servers
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Detect if NTP configuration file is present
  find:
    path: /etc
    patterns: ntp.conf
  register: ntp_server_config
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(a)
  - NIST-800-53-AU-8(2)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.3
  - chronyd_or_ntpd_specify_multiple_servers
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Configure multiple time servers in NTP config
  lineinfile:
    path: /etc/chrony.conf
    line: pool {{ item }}
    state: present
    create: true
  loop: '{{ var_multiple_time_servers.split(",") }}'
  when:
  - '"kernel" in ansible_facts.packages'
  - ( "chrony" in ansible_facts.packages or "ntp" in ansible_facts.packages )
  - ntp_server_config.matched == 1
  tags:
  - NIST-800-53-AU-12(1)
  - NIST-800-53-AU-8(1)(a)
  - NIST-800-53-AU-8(2)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.3
  - chronyd_or_ntpd_specify_multiple_servers
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Specify a Remote NTP Server [ref]

Depending on specific functional requirements of a concrete production environment, the Red Hat Virtualization 4 system can be configured to utilize the services of the chronyd NTP daemon (the default), or services of the ntpd NTP daemon. Refer to https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/ch-configuring_ntp_using_the_chrony_suite for more detailed comparison of the features of both of the choices, and for further guidance how to choose between the two NTP daemons.
To specify a remote NTP server for time synchronization, perform the following:

if the system is configured to use the chronyd as the NTP daemon (the default), edit the file /etc/chrony.conf as follows,
if the system is configured to use the ntpd as the NTP daemon, edit the file /etc/ntp.conf as documented below.

Add or correct the following lines, substituting the IP or hostname of a remote NTP server for ntpserver:

server ntpserver

This instructs the NTP software to contact that remote server to obtain time data.

Rationale:

Synchronizing with an NTP server makes it possible to collate system logs from multiple sources or correlate computer events with real time events.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_chronyd_or_ntpd_specify_remote_server

References:

cis-csc	1, 14, 15, 16, 3, 5, 6
cobit5	APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01
cui	3.3.7
disa	CCI-000160, CCI-001891
isa-62443-2009	4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1
nist	CM-6(a), AU-8(1)(a), AU-8(2), AU-12(1)
nist-csf	PR.PT-1
pcidss	Req-10.4.1, Req-10.4.3
app-srg-ctr	SRG-APP-000116-CTR-000235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && { ( rpm --quiet -q chrony || rpm --quiet -q ntp ); }; then

var_multiple_time_servers='0.rhel.pool.ntp.org,1.rhel.pool.ntp.org,2.rhel.pool.ntp.org,3.rhel.pool.ntp.org'


config_file="/etc/ntp.conf"
/usr/sbin/pidof ntpd || config_file="/etc/chrony.conf"

if ! grep -q ^server "$config_file" ; then
  if ! grep -q '#[[:space:]]*server' "$config_file" ; then
    for server in $(echo "$var_multiple_time_servers" | tr ',' '\n') ; do
      printf '\nserver %s' "$server" >> "$config_file"
    done
  else
    sed -i 's/#[ \t]*server/server/g' "$config_file"
  fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Group Obsolete Services Group contains 6 groups and 15 rules

[ref] This section discusses a number of network-visible services which have historically caused problems for system security, and for which disabling or severely limiting the service has been the best available guidance for some time. As a result of this, many of these services are not installed as part of Red Hat Virtualization 4 by default.

Organizations which are running these services should switch to more secure equivalents as soon as possible. If it remains absolutely necessary to run one of these services for legacy reasons, care should be taken to restrict the service as much as possible, for instance by configuring host firewall software such as iptables to restrict access to the vulnerable service to only those remote hosts which have a known need to use it.

Group Xinetd Group contains 2 rules

[ref] The xinetd service acts as a dedicated listener for some network services (mostly, obsolete ones) and can be used to provide access controls and perform some logging. It has been largely obsoleted by other features, and it is not installed by default. The older Inetd service is not even available as part of Red Hat Virtualization 4.

Rule Uninstall xinetd Package [ref]

The xinetd package can be removed with the following command:

$ sudo yum erase xinetd

Rationale:

Removing the xinetd package decreases the risk of the xinetd service's accidental (or intentional) activation.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_package_xinetd_removed

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
disa	CCI-000305
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
anssi	R62
pcidss4	2.2.4, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

# CAUTION: This remediation script will remove xinetd
#	   from the system, and may remove any packages
#	   that depend on xinetd. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "xinetd" ; then
yum remove -y "xinetd"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.4
  - disable_strategy
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - package_xinetd_removed

- name: Ensure xinetd is removed
  package:
    name: xinetd
    state: absent
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.4
  - disable_strategy
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - package_xinetd_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=xinetd

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_xinetd

class remove_xinetd {
  package { 'xinetd':
    ensure => 'purged',
  }
}

Rule Disable xinetd Service [ref]

The xinetd service can be disabled with the following command:

$ sudo systemctl mask --now xinetd.service

Rationale:

The xinetd service provides a dedicated listener service for some programs, which is no longer necessary for commonly-used network services. Disabling it ensures that these uncommon services are not running, and also prevents attacks against xinetd itself.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_xinetd_disabled

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
cui	3.4.7
disa	CCI-000305
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'xinetd.service'
"$SYSTEMCTL_EXEC" disable 'xinetd.service'
"$SYSTEMCTL_EXEC" mask 'xinetd.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files xinetd.socket; then
    "$SYSTEMCTL_EXEC" stop 'xinetd.socket'
    "$SYSTEMCTL_EXEC" mask 'xinetd.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'xinetd.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
masked = ["xinetd"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_xinetd_disabled

- name: Disable xinetd Service - Collect systemd Services Present in the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_xinetd_disabled

- name: Disable xinetd Service - Ensure xinetd.service is Masked
  ansible.builtin.systemd:
    name: xinetd.service
    state: stopped
    enabled: false
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - service_exists.stdout_lines is search("xinetd.service", multiline=True)
  tags:
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_xinetd_disabled

- name: Unit Socket Exists - xinetd.socket
  ansible.builtin.command: systemctl -q list-unit-files xinetd.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_xinetd_disabled

- name: Disable xinetd Service - Disable Socket xinetd
  ansible.builtin.systemd:
    name: xinetd.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - socket_file_exists.stdout_lines is search("xinetd.socket", multiline=True)
  tags:
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_xinetd_disabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include disable_xinetd

class disable_xinetd {
  service {'xinetd':
    enable => false,
    ensure => 'stopped',
  }
}

Group NIS Group contains 1 rule

[ref] The Network Information Service (NIS), also known as 'Yellow Pages' (YP), and its successor NIS+ have been made obsolete by Kerberos, LDAP, and other modern centralized authentication services. NIS should not be used because it suffers from security problems inherent in its design, such as inadequate protection of important authentication information.

Rule Uninstall ypserv Package [ref]

The ypserv package can be removed with the following command:

$ sudo yum erase ypserv

Rationale:

The NIS service provides an unencrypted authentication service which does not provide for the confidentiality and integrity of user passwords or the remote session. Removing the ypserv package decreases the risk of the accidental (or intentional) activation of NIS or NIS+ services.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_package_ypserv_removed

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
disa	CCI-000381
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
pcidss	Req-2.2.2
os-srg	SRG-OS-000095-GPOS-00049
anssi	R62
pcidss4	2.2.4, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


# CAUTION: This remediation script will remove ypserv
#	   from the system, and may remove any packages
#	   that depend on ypserv. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "ypserv" ; then
yum remove -y "ypserv"
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Ensure ypserv is removed
  package:
    name: ypserv
    state: absent
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - PCI-DSS-Req-2.2.2
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.4
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - package_ypserv_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=ypserv

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_ypserv

class remove_ypserv {
  package { 'ypserv':
    ensure => 'purged',
  }
}

Group Rlogin, Rsh, and Rexec Group contains 5 rules

[ref] The Berkeley r-commands are legacy services which allow cleartext remote access and have an insecure trust model.

Rule Uninstall rsh-server Package [ref]

The rsh-server package can be removed with the following command:

$ sudo yum erase rsh-server

Rationale:

The rsh-server service provides unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session and has very weak authentication. If a privileged user were to login using this service, the privileged user password could be compromised. The rsh-server package provides several obsolete and insecure network services. Removing it decreases the risk of those services' accidental (or intentional) activation.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_package_rsh-server_removed

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
disa	CCI-000381
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000095-GPOS-00049
anssi	R62
pcidss4	2.2.4, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


# CAUTION: This remediation script will remove rsh-server
#	   from the system, and may remove any packages
#	   that depend on rsh-server. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "rsh-server" ; then
yum remove -y "rsh-server"
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Ensure rsh-server is removed
  package:
    name: rsh-server
    state: absent
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.4
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - package_rsh-server_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=rsh-server

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_rsh-server

class remove_rsh-server {
  package { 'rsh-server':
    ensure => 'purged',
  }
}

Rule Disable rexec Service [ref]

The rexec service, which is available with the rsh-server package and runs as a service through xinetd or separately as a systemd socket, should be disabled. If using xinetd, set disable to yes in /etc/xinetd.d/rexec. The rexec socket can be disabled with the following command:

$ sudo systemctl mask --now rexec.socket

Rationale:

The rexec service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_service_rexec_disabled

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
cui	3.1.13, 3.4.7
disa	CCI-000068, CCI-001436
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'rexec.service'
"$SYSTEMCTL_EXEC" disable 'rexec.service'
"$SYSTEMCTL_EXEC" mask 'rexec.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files rexec.socket; then
    "$SYSTEMCTL_EXEC" stop 'rexec.socket'
    "$SYSTEMCTL_EXEC" mask 'rexec.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'rexec.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
masked = ["rexec"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rexec_disabled

- name: Disable rexec Service - Collect systemd Services Present in the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rexec_disabled

- name: Disable rexec Service - Ensure rexec.service is Masked
  ansible.builtin.systemd:
    name: rexec.service
    state: stopped
    enabled: false
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - service_exists.stdout_lines is search("rexec.service", multiline=True)
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rexec_disabled

- name: Unit Socket Exists - rexec.socket
  ansible.builtin.command: systemctl -q list-unit-files rexec.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rexec_disabled

- name: Disable rexec Service - Disable Socket rexec
  ansible.builtin.systemd:
    name: rexec.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - socket_file_exists.stdout_lines is search("rexec.socket", multiline=True)
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rexec_disabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include disable_rexec

class disable_rexec {
  service {'rexec':
    enable => false,
    ensure => 'stopped',
  }
}

Rule Disable rlogin Service [ref]

The rlogin service, which is available with the rsh-server package and runs as a service through xinetd or separately as a systemd socket, should be disabled. If using xinetd, set disable to yes in /etc/xinetd.d/rlogin. The rlogin socket can be disabled with the following command:

$ sudo systemctl mask --now rlogin.socket

Rationale:

The rlogin service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_service_rlogin_disabled

References:

cis-csc	1, 11, 12, 14, 15, 16, 3, 5, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10
cui	3.1.13, 3.4.7
disa	CCI-001436
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c)
nist-csf	PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'rlogin.service'
"$SYSTEMCTL_EXEC" disable 'rlogin.service'
"$SYSTEMCTL_EXEC" mask 'rlogin.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files rlogin.socket; then
    "$SYSTEMCTL_EXEC" stop 'rlogin.socket'
    "$SYSTEMCTL_EXEC" mask 'rlogin.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'rlogin.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
masked = ["rlogin"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rlogin_disabled

- name: Disable rlogin Service - Collect systemd Services Present in the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rlogin_disabled

- name: Disable rlogin Service - Ensure rlogin.service is Masked
  ansible.builtin.systemd:
    name: rlogin.service
    state: stopped
    enabled: false
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - service_exists.stdout_lines is search("rlogin.service", multiline=True)
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rlogin_disabled

- name: Unit Socket Exists - rlogin.socket
  ansible.builtin.command: systemctl -q list-unit-files rlogin.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rlogin_disabled

- name: Disable rlogin Service - Disable Socket rlogin
  ansible.builtin.systemd:
    name: rlogin.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - socket_file_exists.stdout_lines is search("rlogin.socket", multiline=True)
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_rlogin_disabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include disable_rlogin

class disable_rlogin {
  service {'rlogin':
    enable => false,
    ensure => 'stopped',
  }
}

Rule Remove Host-Based Authentication Files [ref]

The shosts.equiv file lists remote hosts and users that are trusted by the local system. To remove these files, run the following command to delete them from any location:

$ sudo rm /[path]/[to]/[file]/shosts.equiv

Rationale:

The shosts.equiv files are used to configure host-based authentication for the system via SSH. Host-based authentication is not sufficient for preventing unauthorized access to the system, as it does not require interactive identification and authentication of a connection request, or for the use of two-factor authentication.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_no_host_based_files

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲


# Identify local mounts
MOUNT_LIST=$(df --local | awk '{ print $6 }')

# Find file on each listed mount point
for cur_mount in ${MOUNT_LIST}
do
	find ${cur_mount} -xdev -type f -name "shosts.equiv" -exec rm -f {} \;
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Remove Host-Based Authentication Files - Define Excluded (Non-Local) File
    Systems and Paths
  ansible.builtin.set_fact:
    excluded_fstypes:
    - afs
    - ceph
    - cifs
    - smb3
    - smbfs
    - sshfs
    - ncpfs
    - ncp
    - nfs
    - nfs4
    - gfs
    - gfs2
    - glusterfs
    - gpfs
    - pvfs2
    - ocfs2
    - lustre
    - davfs
    - fuse.sshfs
    excluded_paths:
    - dev
    - proc
    - run
    - sys
    search_paths: []
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_host_based_files
  - no_reboot_needed
  - restrict_strategy

- name: Remove Host-Based Authentication Files - Find Relevant Root Directories Ignoring
    Pre-Defined Excluded Paths
  ansible.builtin.find:
    paths: /
    file_type: directory
    excludes: '{{ excluded_paths }}'
    hidden: true
    recurse: false
  register: result_relevant_root_dirs
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_host_based_files
  - no_reboot_needed
  - restrict_strategy

- name: Remove Host-Based Authentication Files - Include Relevant Root Directories
    in a List of Paths to be Searched
  ansible.builtin.set_fact:
    search_paths: '{{ search_paths | union([item.path]) }}'
  loop: '{{ result_relevant_root_dirs.files }}'
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_host_based_files
  - no_reboot_needed
  - restrict_strategy

- name: Remove Host-Based Authentication Files - Increment Search Paths List with
    Local Partitions Mount Points
  ansible.builtin.set_fact:
    search_paths: '{{ search_paths | union([item.mount]) }}'
  loop: '{{ ansible_mounts }}'
  when:
  - item.fstype not in excluded_fstypes
  - item.mount != '/'
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_host_based_files
  - no_reboot_needed
  - restrict_strategy

- name: Remove Host-Based Authentication Files - Increment Search Paths List with
    Local NFS File System Targets
  ansible.builtin.set_fact:
    search_paths: '{{ search_paths | union([item.device.split('':'')[1]]) }}'
  loop: '{{ ansible_mounts }}'
  when: item.device is search("localhost:")
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_host_based_files
  - no_reboot_needed
  - restrict_strategy

- name: Remove Host-Based Authentication Files - Define Rule Specific Facts
  ansible.builtin.set_fact:
    shosts_equiv_files:
    - /shosts.equiv
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_host_based_files
  - no_reboot_needed
  - restrict_strategy

- name: Remove Host-Based Authentication Files - Find All shosts.equiv Files in Local
    File Systems
  ansible.builtin.command:
    cmd: find {{ item }} -xdev -type f -name "shosts.equiv"
  loop: '{{ search_paths }}'
  changed_when: false
  register: result_found_shosts_equiv_files
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_host_based_files
  - no_reboot_needed
  - restrict_strategy

- name: Remove Host-Based Authentication Files - Create List of shosts.equiv Files
    Present in Local File Systems
  ansible.builtin.set_fact:
    shosts_equiv_files: '{{ shosts_equiv_files | union(item.stdout_lines) | list }}'
  loop: '{{ result_found_shosts_equiv_files.results }}'
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_host_based_files
  - no_reboot_needed
  - restrict_strategy

- name: Remove Host-Based Authentication Files - Ensure No shosts.equiv Files Are
    Present in the System
  ansible.builtin.file:
    path: '{{ item }}'
    state: absent
  loop: '{{ shosts_equiv_files }}'
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_host_based_files
  - no_reboot_needed
  - restrict_strategy

Rule Remove User Host-Based Authentication Files [ref]

The ~/.shosts (in each user's home directory) files list remote hosts and users that are trusted by the local system. To remove these files, run the following command to delete them from any location:

$ sudo find / -name '.shosts' -type f -delete

Rationale:

The .shosts files are used to configure host-based authentication for individual users or the system via SSH. Host-based authentication is not sufficient for preventing unauthorized access to the system, as it does not require interactive identification and authentication of a connection request, or for the use of two-factor authentication.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_no_user_host_based_files

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲


# Identify local mounts
MOUNT_LIST=$(df --local | awk '{ print $6 }')

# Find file on each listed mount point
for cur_mount in ${MOUNT_LIST}
do
	find ${cur_mount} -xdev -type f -name ".shosts" -exec rm -f {} \;
done

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Remove User Host-Based Authentication Files - Define Excluded (Non-Local)
    File Systems and Paths
  ansible.builtin.set_fact:
    excluded_fstypes:
    - afs
    - ceph
    - cifs
    - smb3
    - smbfs
    - sshfs
    - ncpfs
    - ncp
    - nfs
    - nfs4
    - gfs
    - gfs2
    - glusterfs
    - gpfs
    - pvfs2
    - ocfs2
    - lustre
    - davfs
    - fuse.sshfs
    excluded_paths:
    - dev
    - proc
    - run
    - sys
    search_paths: []
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - no_user_host_based_files
  - restrict_strategy

- name: Remove User Host-Based Authentication Files - Find Relevant Root Directories
    Ignoring Pre-Defined Excluded Paths
  ansible.builtin.find:
    paths: /
    file_type: directory
    excludes: '{{ excluded_paths }}'
    hidden: true
    recurse: false
  register: result_relevant_root_dirs
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - no_user_host_based_files
  - restrict_strategy

- name: Remove User Host-Based Authentication Files - Include Relevant Root Directories
    in a List of Paths to be Searched
  ansible.builtin.set_fact:
    search_paths: '{{ search_paths | union([item.path]) }}'
  loop: '{{ result_relevant_root_dirs.files }}'
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - no_user_host_based_files
  - restrict_strategy

- name: Remove User Host-Based Authentication Files - Increment Search Paths List
    with Local Partitions Mount Points
  ansible.builtin.set_fact:
    search_paths: '{{ search_paths | union([item.mount]) }}'
  loop: '{{ ansible_mounts }}'
  when:
  - item.fstype not in excluded_fstypes
  - item.mount != '/'
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - no_user_host_based_files
  - restrict_strategy

- name: Remove User Host-Based Authentication Files - Increment Search Paths List
    with Local NFS File System Targets
  ansible.builtin.set_fact:
    search_paths: '{{ search_paths | union([item.device.split('':'')[1]]) }}'
  loop: '{{ ansible_mounts }}'
  when: item.device is search("localhost:")
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - no_user_host_based_files
  - restrict_strategy

- name: Remove User Host-Based Authentication Files - Define Rule Specific Facts
  ansible.builtin.set_fact:
    user_shosts_files:
    - /.shosts
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - no_user_host_based_files
  - restrict_strategy

- name: Remove User Host-Based Authentication Files - Find All .shosts Files in Local
    File Systems
  ansible.builtin.command:
    cmd: find {{ item }} -xdev -type f -name ".shosts"
  loop: '{{ search_paths }}'
  changed_when: false
  register: result_found_shosts_files
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - no_user_host_based_files
  - restrict_strategy

- name: Remove User Host-Based Authentication Files - Create List of .shosts Files
    Present in Local File Systems
  ansible.builtin.set_fact:
    user_shosts_files: '{{ user_shosts_files | union(item.stdout_lines) | list }}'
  loop: '{{ result_found_shosts_files.results }}'
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - no_user_host_based_files
  - restrict_strategy

- name: Remove User Host-Based Authentication Files - Ensure No .shosts Files Are
    Present in the System
  ansible.builtin.file:
    path: '{{ item }}'
    state: absent
  loop: '{{ user_shosts_files }}'
  tags:
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - no_user_host_based_files
  - restrict_strategy

Group Chat/Messaging Services Group contains 2 rules

[ref] The talk software makes it possible for users to send and receive messages across systems through a terminal session.

Rule Uninstall talk-server Package [ref]

The talk-server package can be removed with the following command:

 $ sudo yum erase talk-server

Rationale:

The talk software presents a security risk as it uses unencrypted protocols for communications. Removing the talk-server package decreases the risk of the accidental (or intentional) activation of talk services.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_talk-server_removed

References:

hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
anssi	R62
pcidss4	2.2.4, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


# CAUTION: This remediation script will remove talk-server
#	   from the system, and may remove any packages
#	   that depend on talk-server. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "talk-server" ; then
yum remove -y "talk-server"
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Ensure talk-server is removed
  package:
    name: talk-server
    state: absent
  tags:
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.4
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_talk-server_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=talk-server

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_talk-server

class remove_talk-server {
  package { 'talk-server':
    ensure => 'purged',
  }
}

Rule Uninstall talk Package [ref]

The talk package contains the client program for the Internet talk protocol, which allows the user to chat with other users on different systems. Talk is a communication program which copies lines from one terminal to the terminal of another user. The talk package can be removed with the following command:

$ sudo yum erase talk

Rationale:

The talk software presents a security risk as it uses unencrypted protocols for communications. Removing the talk package decreases the risk of the accidental (or intentional) activation of talk client program.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_talk_removed

References:

hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
anssi	R62
pcidss4	2.2.4, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


# CAUTION: This remediation script will remove talk
#	   from the system, and may remove any packages
#	   that depend on talk. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "talk" ; then
yum remove -y "talk"
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Ensure talk is removed
  package:
    name: talk
    state: absent
  tags:
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.4
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_talk_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=talk

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_talk

class remove_talk {
  package { 'talk':
    ensure => 'purged',
  }
}

Group Telnet Group contains 3 rules

[ref] The telnet protocol does not provide confidentiality or integrity for information transmitted on the network. This includes authentication information such as passwords. Organizations which use telnet should be actively working to migrate to a more secure protocol.

Rule Uninstall telnet-server Package [ref]

The telnet-server package can be removed with the following command:

$ sudo yum erase telnet-server

Rationale:

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities are often overlooked and therefore may remain unsecure. They increase the risk to the platform by providing additional attack vectors.
The telnet service provides an unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to login using this service, the privileged user password could be compromised.
Removing the telnet-server package decreases the risk of the telnet service's accidental (or intentional) activation.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_package_telnet-server_removed

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
disa	CCI-000381
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
pcidss	Req-2.2.2
os-srg	SRG-OS-000095-GPOS-00049
anssi	R62
pcidss4	2.2.4, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


# CAUTION: This remediation script will remove telnet-server
#	   from the system, and may remove any packages
#	   that depend on telnet-server. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "telnet-server" ; then
yum remove -y "telnet-server"
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Ensure telnet-server is removed
  package:
    name: telnet-server
    state: absent
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-2.2.2
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.4
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - package_telnet-server_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=telnet-server

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_telnet-server

class remove_telnet-server {
  package { 'telnet-server':
    ensure => 'purged',
  }
}

Rule Remove telnet Clients [ref]

The telnet client allows users to start connections to other systems via the telnet protocol.

Rationale:

The telnet protocol is insecure and unencrypted. The use of an unencrypted transmission medium could allow an unauthorized user to steal credentials. The ssh package provides an encrypted session and stronger security and is included in Red Hat Virtualization 4.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_package_telnet_removed

References:

cui	3.1.13
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
iso27001-2013	A.8.2.3, A.13.1.1, A.13.2.1, A.13.2.3, A.14.1.2, A.14.1.3
anssi	R62
pcidss4	2.2.4, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


# CAUTION: This remediation script will remove telnet
#	   from the system, and may remove any packages
#	   that depend on telnet. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "telnet" ; then
yum remove -y "telnet"
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Ensure telnet is removed
  package:
    name: telnet
    state: absent
  tags:
  - NIST-800-171-3.1.13
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.4
  - disable_strategy
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - package_telnet_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=telnet

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_telnet

class remove_telnet {
  package { 'telnet':
    ensure => 'purged',
  }
}

Rule Disable telnet Service [ref]

Make sure that the activation of the telnet service on system boot is disabled. The telnet socket can be disabled with the following command:

$ sudo systemctl mask --now telnet.socket

Warning: If the system relies on xinetd to manage telnet sessions, ensure the telnet service is disabled by the following line: disable = yes. Note that the xinetd file for telnet is not created automatically, therefore it might have different names.

Rationale:

The telnet protocol uses unencrypted network communication, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network. The telnet protocol is also subject to man-in-the-middle attacks.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_service_telnet_disabled

References:

cis-csc	1, 11, 12, 14, 15, 16, 3, 5, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10
cui	3.1.13, 3.4.7
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c)
nist-csf	PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if ( rpm --quiet -q telnet-server && rpm --quiet -q kernel ); then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'telnet.service'
"$SYSTEMCTL_EXEC" disable 'telnet.service'
"$SYSTEMCTL_EXEC" mask 'telnet.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files telnet.socket; then
    "$SYSTEMCTL_EXEC" stop 'telnet.socket'
    "$SYSTEMCTL_EXEC" mask 'telnet.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'telnet.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
masked = ["telnet"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_telnet_disabled

- name: Disable telnet Service - Collect systemd Services Present in the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: ( "telnet-server" in ansible_facts.packages and "kernel" in ansible_facts.packages
    )
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_telnet_disabled

- name: Disable telnet Service - Ensure telnet.service is Masked
  ansible.builtin.systemd:
    name: telnet.service
    state: stopped
    enabled: false
    masked: true
  when:
  - ( "telnet-server" in ansible_facts.packages and "kernel" in ansible_facts.packages
    )
  - service_exists.stdout_lines is search("telnet.service", multiline=True)
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_telnet_disabled

- name: Unit Socket Exists - telnet.socket
  ansible.builtin.command: systemctl -q list-unit-files telnet.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: ( "telnet-server" in ansible_facts.packages and "kernel" in ansible_facts.packages
    )
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_telnet_disabled

- name: Disable telnet Service - Disable Socket telnet
  ansible.builtin.systemd:
    name: telnet.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - ( "telnet-server" in ansible_facts.packages and "kernel" in ansible_facts.packages
    )
  - socket_file_exists.stdout_lines is search("telnet.socket", multiline=True)
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.4.7
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-5(1)(c)
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - service_telnet_disabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include disable_telnet

class disable_telnet {
  service {'telnet':
    enable => false,
    ensure => 'stopped',
  }
}

Group TFTP Server Group contains 2 rules

[ref] TFTP is a lightweight version of the FTP protocol which has traditionally been used to configure networking equipment. However, TFTP provides little security, and modern versions of networking operating systems frequently support configuration via SSH or other more secure protocols. A TFTP server should be run only if no more secure method of supporting existing equipment can be found.

Rule Uninstall tftp-server Package [ref]

The tftp-server package can be removed with the following command:

 $ sudo yum erase tftp-server

Rationale:

Removing the tftp-server package decreases the risk of the accidental (or intentional) activation of tftp services.

If TFTP is required for operational support (such as transmission of router configurations), its use must be documented with the Information Systems Securty Manager (ISSM), restricted to only authorized personnel, and have access control rules established.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_package_tftp-server_removed

References:

cis-csc	11, 12, 14, 15, 3, 8, 9
cobit5	APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R62
pcidss4	2.2.4, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


# CAUTION: This remediation script will remove tftp-server
#	   from the system, and may remove any packages
#	   that depend on tftp-server. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "tftp-server" ; then
yum remove -y "tftp-server"
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Ensure tftp-server is removed
  package:
    name: tftp-server
    state: absent
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.4
  - disable_strategy
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - package_tftp-server_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=tftp-server

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_tftp-server

class remove_tftp-server {
  package { 'tftp-server':
    ensure => 'purged',
  }
}

Rule Ensure tftp Daemon Uses Secure Mode [ref]

If running the Trivial File Transfer Protocol (TFTP) service is necessary, it should be configured to change its root directory at startup. To do so, ensure /etc/xinetd.d/tftp includes -s as a command line argument, as shown in the following example:

server_args = -s /var/lib/tftpboot

Rationale:

Using the -s option causes the TFTP service to only serve files from the given directory. Serving files from an intentionally-specified directory reduces the risk of sharing files which should remain private.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_tftpd_uses_secure_mode

References:

cis-csc	11, 12, 13, 14, 15, 16, 18, 3, 5, 8, 9
cobit5	APO01.06, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06
disa	CCI-000366
isa-62443-2009	4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(b), AC-6, CM-7(a)
nist-csf	PR.AC-3, PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q tftp-server; then

var_tftpd_secure_directory='/var/lib/tftpboot'


if grep -q 'server_args' /etc/xinetd.d/tftp; then
    sed -i -E "s;^([[:blank:]]*server_args[[:blank:]]+=[[:blank:]]+.*?)(-s[[:blank:]]+[[:graph:]]+)*(.*)$;\1 -s $var_tftpd_secure_directory \3;" /etc/xinetd.d/tftp
else
    echo "server_args = -s $var_tftpd_secure_directory" >> /etc/xinetd.d/tftp
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-7(a)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - tftpd_uses_secure_mode
- name: XCCDF Value var_tftpd_secure_directory # promote to variable
  set_fact:
    var_tftpd_secure_directory: !!str /var/lib/tftpboot
  tags:
    - always

- name: Find out if the file exists and contains the line configuring server arguments
  find:
    path: /etc/xinetd.d
    patterns: tftp
    contains: ^[\s]+server_args.*$
  register: tftpd_secure_config_line
  when: '"tftp-server" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-7(a)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - tftpd_uses_secure_mode

- name: Ensure that TFTP server is configured to start with secure directory
  lineinfile:
    path: /etc/xinetd.d/tftp
    regexp: ^[\s]*(server_args[\s]+=[\s]+.*?)(-s[\s]+[/\.\w]+)*(.*)$
    line: \1 -s {{ var_tftpd_secure_directory }} \3
    state: present
    backrefs: true
  when:
  - '"tftp-server" in ansible_facts.packages'
  - tftpd_secure_config_line is defined and tftpd_secure_config_line.matched > 0
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-7(a)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - tftpd_uses_secure_mode

- name: Insert correct config line to start TFTP server with secure directory
  lineinfile:
    path: /etc/xinetd.d/tftp
    line: server_args = -s {{ var_tftpd_secure_directory }}
    state: present
    create: true
  when:
  - '"tftp-server" in ansible_facts.packages'
  - tftpd_secure_config_line is defined and tftpd_secure_config_line.matched == 0
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-7(a)
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - tftpd_uses_secure_mode

Group Network Routing Group contains 1 group and 1 rule

[ref] A router is a very desirable target for a potential adversary because they fulfill a variety of infrastructure networking roles such as access to network segments, gateways to other networks, filtering, etc. Therefore, if one is required, the system acting as a router should be dedicated to that purpose alone and be stored in a physically secure location. The system's default routing software is Quagga, and provided in an RPM package of the same name.

Group Disable Quagga if Possible Group contains 1 rule

[ref] If Quagga was installed and activated, but the system does not need to act as a router, then it should be disabled and removed.

Rule Disable Quagga Service [ref]

The zebra service can be disabled with the following command:

$ sudo systemctl mask --now zebra.service

Rationale:

Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If routing daemons are used when not required, system network information may be unnecessarily transmitted across the network.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_zebra_disabled

References:

cis-csc	12, 15, 8
cobit5	APO13.01, DSS05.02
disa	CCI-000366
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2013	SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.13.1.1, A.13.2.1, A.14.1.3
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" stop 'zebra.service'
"$SYSTEMCTL_EXEC" disable 'zebra.service'
"$SYSTEMCTL_EXEC" mask 'zebra.service'
# Disable socket activation if we have a unit file for it
if "$SYSTEMCTL_EXEC" -q list-unit-files zebra.socket; then
    "$SYSTEMCTL_EXEC" stop 'zebra.socket'
    "$SYSTEMCTL_EXEC" mask 'zebra.socket'
fi
# The service may not be running because it has been started and failed,
# so let's reset the state so OVAL checks pass.
# Service should be 'inactive', not 'failed' after reboot though.
"$SYSTEMCTL_EXEC" reset-failed 'zebra.service' || true

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
masked = ["zebra"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_zebra_disabled

- name: Disable Quagga Service - Collect systemd Services Present in the System
  ansible.builtin.command: systemctl -q list-unit-files --type service
  register: service_exists
  changed_when: false
  failed_when: service_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_zebra_disabled

- name: Disable Quagga Service - Ensure zebra.service is Masked
  ansible.builtin.systemd:
    name: zebra.service
    state: stopped
    enabled: false
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - service_exists.stdout_lines is search("zebra.service", multiline=True)
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_zebra_disabled

- name: Unit Socket Exists - zebra.socket
  ansible.builtin.command: systemctl -q list-unit-files zebra.socket
  register: socket_file_exists
  changed_when: false
  failed_when: socket_file_exists.rc not in [0, 1]
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_zebra_disabled

- name: Disable Quagga Service - Disable Socket zebra
  ansible.builtin.systemd:
    name: zebra.socket
    enabled: false
    state: stopped
    masked: true
  when:
  - '"kernel" in ansible_facts.packages'
  - socket_file_exists.stdout_lines is search("zebra.socket", multiline=True)
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_zebra_disabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include disable_zebra

class disable_zebra {
  service {'zebra':
    enable => false,
    ensure => 'stopped',
  }
}

Group SSH Server Group contains 1 group and 19 rules

[ref] The SSH protocol is recommended for remote login and remote file transfer. SSH provides confidentiality and integrity for data exchanged between two systems, as well as server authentication, through the use of public key cryptography. The implementation included with the system is called OpenSSH, and more detailed documentation is available from its website, https://www.openssh.com. Its server program is called sshd and provided by the RPM package openssh-server.

Group Configure OpenSSH Server if Necessary Group contains 15 rules

[ref] If the system needs to act as an SSH server, then certain changes should be made to the OpenSSH daemon configuration file /etc/ssh/sshd_config. The following recommendations can be applied to this file. See the sshd_config(5) man page for more detailed information.

Rule Set SSH Client Alive Count Max to zero [ref]

The SSH server sends at most ClientAliveCountMax messages during a SSH session and waits for a response from the SSH client. The option ClientAliveInterval configures timeout after each ClientAliveCountMax message. If the SSH server does not receive a response from the client, then the connection is considered unresponsive and terminated. To ensure the SSH timeout occurs precisely when the ClientAliveInterval is set, set the ClientAliveCountMax to value of 0 in /etc/ssh/sshd_config:

Rationale:

This ensures a user login will be terminated as soon as the ClientAliveInterval is reached.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_set_keepalive_0

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8
cjis	5.5.6
cobit5	APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.1.11
disa	CCI-000879, CCI-001133, CCI-002361
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2
pcidss	Req-8.1.8
os-srg	SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*ClientAliveCountMax\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "ClientAliveCountMax 0" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.11
  - NIST-800-53-AC-12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-2(5)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-10
  - PCI-DSS-Req-8.1.8
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_set_keepalive_0

- name: Set SSH Client Alive Count Max to zero
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*ClientAliveCountMax\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*ClientAliveCountMax\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*ClientAliveCountMax\s+
      line: ClientAliveCountMax 0
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.11
  - NIST-800-53-AC-12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-2(5)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-10
  - PCI-DSS-Req-8.1.8
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_set_keepalive_0

Rule Set SSH Client Alive Interval [ref]

SSH allows administrators to set a network responsiveness timeout interval. After this interval has passed, the unresponsive client will be automatically logged out.

To set this timeout interval, edit the following line in /etc/ssh/sshd_config as follows:

ClientAliveInterval 600

The timeout interval is given in seconds. For example, have a timeout of 10 minutes, set interval to 600.

If a shorter timeout has already been set for the login shell, that value will preempt any SSH setting made in /etc/ssh/sshd_config. Keep in mind that some processes may stop SSH from correctly detecting that the user is idle.

Warning: SSH disconnecting unresponsive clients will not have desired effect without also configuring ClientAliveCountMax in the SSH service configuration.

Warning: Following conditions may prevent the SSH session to time out:

Remote processes on the remote machine generates output. As the output has to be transferred over the network to the client, the timeout is reset every time such transfer happens.
Any scp or sftp activity by the same user to the host resets the timeout.

Rationale:

Terminating an idle ssh session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been let unattended.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_set_idle_timeout

References:

cis-csc	1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8
cjis	5.5.6
cobit5	APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
cui	3.1.11
disa	CCI-001133, CCI-002361, CCI-002891
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	CM-6(a), AC-17(a), AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2
pcidss	Req-8.1.8
os-srg	SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000395-GPOS-00175
pcidss4	8.2.8, 8.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

sshd_idle_timeout_value='600'



if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*ClientAliveInterval\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "ClientAliveInterval $sshd_idle_timeout_value" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.11
  - NIST-800-53-AC-12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-2(5)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-10
  - PCI-DSS-Req-8.1.8
  - PCI-DSSv4-8.2
  - PCI-DSSv4-8.2.8
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_set_idle_timeout
- name: XCCDF Value sshd_idle_timeout_value # promote to variable
  set_fact:
    sshd_idle_timeout_value: !!str 600
  tags:
    - always

- name: Set SSH Client Alive Interval
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*ClientAliveInterval\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*ClientAliveInterval\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*ClientAliveInterval\s+
      line: ClientAliveInterval {{ sshd_idle_timeout_value }}
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.11
  - NIST-800-53-AC-12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-2(5)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-10
  - PCI-DSS-Req-8.1.8
  - PCI-DSSv4-8.2
  - PCI-DSSv4-8.2.8
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_set_idle_timeout

Rule Disable Host-Based Authentication [ref]

SSH's cryptographic host-based authentication is more secure than .rhosts authentication. However, it is not recommended that hosts unilaterally trust one another, even within an organization.
The default SSH configuration disables host-based authentication. The appropriate configuration is used if no value is set for HostbasedAuthentication.
To explicitly disable host-based authentication, add or correct the following line in /etc/ssh/sshd_config:

HostbasedAuthentication no

Rationale:

SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_disable_host_auth

References:

cis-csc	11, 12, 14, 15, 16, 18, 3, 5, 9
cjis	5.5.6
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06
cui	3.1.12
disa	CCI-000366
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	AC-3, AC-17(a), CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-4, PR.AC-6, PR.IP-1, PR.PT-3
ospp	FIA_UAU.1
os-srg	SRG-OS-000480-GPOS-00229
pcidss4	8.3.1, 8.3

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*HostbasedAuthentication\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "HostbasedAuthentication no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.1
  - disable_host_auth
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Disable Host-Based Authentication
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*HostbasedAuthentication\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*HostbasedAuthentication\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*HostbasedAuthentication\s+
      line: HostbasedAuthentication no
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSSv4-8.3
  - PCI-DSSv4-8.3.1
  - disable_host_auth
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Enable SSH Server firewalld Firewall Exception [ref]

If the SSH server is in use, inbound connections to SSH's port should be allowed to permit remote access through SSH. In more restrictive firewalld settings, the SSH port should be added to the proper firewalld zone in order to allow SSH remote access.

To configure firewalld to allow ssh access, run the following command(s):

firewall-cmd --permanent --add-service=ssh

Then run the following command to load the newly created rule(s):

firewall-cmd --reload

Warning: The remediation for this rule uses firewall-cmd and nmcli tools. Therefore, it will only be executed if firewalld and NetworkManager services are running. Otherwise, the remediation will be aborted and a informative message will be shown in the remediation report. These respective services will not be started in order to preserve any intentional change in network components related to firewall and network interfaces.

Warning: This rule also checks if the SSH port was modified by the administrator in the firewalld services definitions and is reflecting the expected port number. Although this is checked, fixing the custom ssh.xml file placed by the administrator at /etc/firewalld/services it is not in the scope of the remediation since there is no reliable way to manually change the respective file. If the default SSH port is modified, it is on the administrator responsibility to ensure the firewalld customizations in the service port level are properly configured.

Rationale:

If inbound SSH connections are expected, adding the SSH port to the proper firewalld zone will allow remote access through the SSH port.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_firewalld_sshd_port_enabled

References:

cui	3.1.12
disa	CCI-000382
ism	1416
nist	AC-17(a), CM-6(b), CM-7(a), CM-7(b)
os-srg	SRG-OS-000096-GPOS-00050

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "firewalld" ; then
    yum install -y "firewalld"
fi
if ! rpm -q --quiet "NetworkManager" ; then
    yum install -y "NetworkManager"
fi
firewalld_sshd_zone='public'


if [[ "$OSCAP_BOOTC_BUILD" == "YES" ]]; then
    # By default, NetworkManager interfaces are created only once
    # container image is booted so we do not have information about
    # what interfaces will be created during container build time.
    # Therefore, we will rely on NetworkManager to automatically assign
    # interfaces to the default firewalld zone. For more details see:
    # https://firewalld.org/documentation/man-pages/firewalld.zone.html
    # https://firewalld.org/documentation/zone/connections-interfaces-and-sources.html
    # That also means this remediation only works if zone defined in
    # the firewalld_sshd_zone variable equals to the default zone of firewalld.
    default_zone=$(firewall-offline-cmd --get-default-zone)
    if [ "$firewalld_sshd_zone" != "$default_zone" ]; then
        echo "Firewalld default zone ($default_zone) and pre-set zone for sshd ($firewalld_sshd_zone) differ. Remediation aborted!" >&2
        exit 1
    fi

    # Make sure default zone is set in all existing NetworkManager keyfiles.
    while IFS= read -r -d '' file; do
        sed "s|^\s*zone=.*$|zone=$firewalld_sshd_zone|g" "$file"
    done < <(find /etc/NetworkManager/system-connections -maxdepth 1 -name "*.nmconnection" -print0)

    firewall-offline-cmd --zone="$firewalld_sshd_zone" --add-service=ssh
else
    if test "$(stat -c %d:%i /)" != "$(stat -c %d:%i /proc/1/root/.)"; then
        # TODO: NM (nmcli) now has --offline mode support, and it could operate without NM service.
        # See: https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1183
        # The feature is not quite straighforward (and probably incomplete), though.
        echo "Not applicable in offline mode. Remediation aborted!"
    else
        if systemctl is-active NetworkManager && systemctl is-active firewalld; then
            # First make sure the SSH service is enabled in run-time for the proper zone.
            # This is to avoid connection issues when new interfaces are addeded to this zone.
            firewall-cmd --zone="$firewalld_sshd_zone" --add-service=ssh

            # This will collect all NetworkManager connections names
            readarray -t nm_connections < <(nmcli -g UUID,TYPE con | grep -v loopback | awk -F ':' '{ print $1 }')
            # If the connection is not yet assigned to a firewalld zone, assign it to the proper zone.
            # This will not change connections which are already assigned to any firewalld zone.
            for connection in "${nm_connections[@]}"; do
                current_zone=$(nmcli -f connection.zone connection show "$connection" | awk '{ print $2}')
                if [ $current_zone = "--" ]; then
                    nmcli connection modify "$connection" connection.zone $firewalld_sshd_zone
                fi
            done
            systemctl restart NetworkManager

            # Active zones are zones with at least one interface assigned to it.
            # It is possible that traffic is coming by any active interface and consequently any
            # active zone. So, this make sure all active zones are permanently allowing SSH service.
            readarray -t firewalld_active_zones < <(firewall-cmd --get-active-zones | grep -v "^ " | cut -d " " -f 1)
            for zone in "${firewalld_active_zones[@]}"; do
                firewall-cmd --permanent --zone="$zone" --add-service=ssh
            done
            firewall-cmd --reload
        else
            echo "The firewalld or NetworkManager service is not active. Remediation aborted!"
        fi
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - firewalld_sshd_port_enabled
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value firewalld_sshd_zone # promote to variable
  set_fact:
    firewalld_sshd_zone: !!str public
  tags:
    - always

- name: Enable SSH Server firewalld Firewall Exception - Ensure firewalld and NetworkManager
    packages are installed
  ansible.builtin.package:
    name: '{{ item }}'
    state: present
  with_items:
  - firewalld
  - NetworkManager
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - firewalld_sshd_port_enabled
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Enable SSH Server firewalld Firewall Exception - Collect facts about system
    services
  ansible.builtin.service_facts: null
  register: result_services_states
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - firewalld_sshd_port_enabled
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Enable SSH Server firewalld Firewall Exception - Remediation is applicable
    if firewalld and NetworkManager services are running
  block:

  - name: Enable SSH Server firewalld Firewall Exception - Collect NetworkManager
      connections names
    ansible.builtin.shell:
      cmd: nmcli -g UUID,TYPE con | grep -v loopback | awk -F ':' '{ print $1 }'
    register: result_nmcli_cmd_connections_names
    changed_when: false

  - name: Enable SSH Server firewalld Firewall Exception - Collect NetworkManager
      connections zones
    ansible.builtin.shell:
      cmd: nmcli -f connection.zone connection show {{ item | trim }} | awk '{ print
        $2}'
    register: result_nmcli_cmd_connections_zones
    changed_when: false
    with_items:
    - '{{ result_nmcli_cmd_connections_names.stdout_lines }}'

  - name: Enable SSH Server firewalld Firewall Exception - Ensure NetworkManager connections
      are assigned to a firewalld zone
    ansible.builtin.command:
      cmd: nmcli connection modify {{ item.0 }} connection.zone {{ firewalld_sshd_zone
        }}
    register: result_nmcli_cmd_connections_assignment
    with_together:
    - '{{ result_nmcli_cmd_connections_names.stdout_lines }}'
    - '{{ result_nmcli_cmd_connections_zones.results }}'
    when:
    - item.1.stdout == '--'

  - name: Enable SSH Server firewalld Firewall Exception - Ensure NetworkManager connections
      changes are applied
    ansible.builtin.service:
      name: NetworkManager
      state: restarted
    when:
    - result_nmcli_cmd_connections_assignment is changed

  - name: Enable SSH Server firewalld Firewall Exception - Collect firewalld active
      zones
    ansible.builtin.shell:
      cmd: firewall-cmd --get-active-zones | grep -v "^ " | cut -d " " -f 1
    register: result_firewall_cmd_zones_names
    changed_when: false

  - name: Enable SSH Server firewalld Firewall Exception - Ensure firewalld zones
      allow SSH
    ansible.builtin.command:
      cmd: firewall-cmd --permanent --zone={{ item }} --add-service=ssh
    register: result_nmcli_cmd_connections_assignment
    changed_when:
    - '''ALREADY_ENABLED'' not in result_nmcli_cmd_connections_assignment.stderr'
    with_items:
    - '{{ result_firewall_cmd_zones_names.stdout_lines }}'

  - name: Enable SSH Server firewalld Firewall Exception - Ensure firewalld changes
      are applied
    ansible.builtin.service:
      name: firewalld
      state: reloaded
    when:
    - result_nmcli_cmd_connections_assignment is changed
  when:
  - '"kernel" in ansible_facts.packages'
  - ansible_facts.services['firewalld.service'].state == 'running'
  - ansible_facts.services['NetworkManager.service'].state == 'running'
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - firewalld_sshd_port_enabled
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Enable SSH Server firewalld Firewall Exception - Informative message based
    on services states
  ansible.builtin.assert:
    that:
    - ansible_facts.services['firewalld.service'].state == 'running'
    - ansible_facts.services['NetworkManager.service'].state == 'running'
    fail_msg:
    - firewalld and NetworkManager services are not active. Remediation aborted!
    - This remediation could not be applied because it depends on firewalld and NetworkManager
      services running.
    - The service is not started by this remediation in order to prevent connection
      issues.
    success_msg:
    - Enable SSH Server firewalld Firewall Exception remediation successfully executed
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - configure_strategy
  - firewalld_sshd_port_enabled
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Disable Compression Or Set Compression to delayed [ref]

Compression is useful for slow network connections over long distances but can cause performance issues on local LANs. If use of compression is required, it should be enabled only after a user has authenticated; otherwise, it should be disabled. To disable compression or delay compression until after a user has successfully authenticated, add or correct the following line in the /etc/ssh/sshd_config file:

Compression no

Rationale:

If compression is allowed in an SSH connection prior to authentication, vulnerabilities in the compression software could result in compromise of the system from an unauthenticated connection, potentially with root privileges.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_disable_compression

References:

cis-csc	11, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05
cui	3.1.12
disa	CCI-000366
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4
nist	AC-17(a), CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

var_sshd_disable_compression='no'



if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*Compression\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "Compression $var_sshd_disable_compression" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_compression
- name: XCCDF Value var_sshd_disable_compression # promote to variable
  set_fact:
    var_sshd_disable_compression: !!str no
  tags:
    - always

- name: Disable Compression Or Set Compression to delayed
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*Compression\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*Compression\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*Compression\s+
      line: Compression {{ var_sshd_disable_compression }}
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_compression

Rule Disable SSH Access via Empty Passwords [ref]

Disallow SSH login with empty passwords. The default SSH configuration disables logins with empty passwords. The appropriate configuration is used if no value is set for PermitEmptyPasswords.
To explicitly disallow SSH login from accounts with empty passwords, add or correct the following line in /etc/ssh/sshd_config:

PermitEmptyPasswords no

Any accounts with empty passwords should be disabled immediately, and PAM configuration should prevent users from being able to assign themselves empty passwords.

Rationale:

Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_sshd_disable_empty_passwords

References:

cis-csc	11, 12, 13, 14, 15, 16, 18, 3, 5, 9
cjis	5.5.6
cobit5	APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06
cui	3.1.1, 3.1.5
disa	CCI-000766, CCI-000366
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	AC-17(a), CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3
ospp	FIA_UAU.1
pcidss	Req-2.2.4
os-srg	SRG-OS-000106-GPOS-00053, SRG-OS-000480-GPOS-00229, SRG-OS-000480-GPOS-00227
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "PermitEmptyPasswords no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_empty_passwords

- name: Disable SSH Access via Empty Passwords
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PermitEmptyPasswords\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PermitEmptyPasswords\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PermitEmptyPasswords\s+
      line: PermitEmptyPasswords no
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_empty_passwords

Rule Disable GSSAPI Authentication [ref]

Unless needed, SSH should not permit extraneous or unnecessary authentication mechanisms like GSSAPI.
The default SSH configuration disallows authentications based on GSSAPI. The appropriate configuration is used if no value is set for GSSAPIAuthentication.
To explicitly disable GSSAPI authentication, add or correct the following line in /etc/ssh/sshd_config:

GSSAPIAuthentication no

Rationale:

GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system's GSSAPI to remote hosts, increasing the attack surface of the system.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_disable_gssapi_auth

References:

cis-csc	11, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05
cui	3.1.12
disa	CCI-000366, CCI-001813
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 7.6
ism	0418, 1055, 1402
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4
nist	CM-7(a), CM-7(b), CM-6(a), AC-17(a)
nist-csf	PR.IP-1
ospp	FTP_ITC_EXT.1, FCS_SSH_EXT.1.2
os-srg	SRG-OS-000364-GPOS-00151, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*GSSAPIAuthentication\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "GSSAPIAuthentication no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_gssapi_auth

- name: Disable GSSAPI Authentication
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*GSSAPIAuthentication\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*GSSAPIAuthentication\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*GSSAPIAuthentication\s+
      line: GSSAPIAuthentication no
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_gssapi_auth

Rule Disable Kerberos Authentication [ref]

Unless needed, SSH should not permit extraneous or unnecessary authentication mechanisms like Kerberos.
The default SSH configuration disallows authentication validation through Kerberos. The appropriate configuration is used if no value is set for KerberosAuthentication.
To explicitly disable Kerberos authentication, add or correct the following line in /etc/ssh/sshd_config:

KerberosAuthentication no

Rationale:

Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos is enabled through SSH, the SSH daemon provides a means of access to the system's Kerberos implementation. Configuring these settings for the SSH daemon provides additional assurance that remote logon via SSH will not use unused methods of authentication, even in the event of misconfiguration elsewhere.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_disable_kerb_auth

References:

cis-csc	11, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05
cui	3.1.12
disa	CCI-000366, CCI-001813
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 7.6
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4
nist	AC-17(a), CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1
ospp	FTP_ITC_EXT.1, FCS_SSH_EXT.1.2
os-srg	SRG-OS-000364-GPOS-00151, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*KerberosAuthentication\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "KerberosAuthentication no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_kerb_auth

- name: Disable Kerberos Authentication
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*KerberosAuthentication\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*KerberosAuthentication\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*KerberosAuthentication\s+
      line: KerberosAuthentication no
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_kerb_auth

Rule Disable SSH Root Login [ref]

The root user should never be allowed to login to a system directly over a network. To disable root login via SSH, add or correct the following line in /etc/ssh/sshd_config:

PermitRootLogin no

Rationale:

Even though the communications channel may be encrypted, an additional layer of security is gained by extending the policy of not logging directly on as root. In addition, logging in with a user-specific account provides individual accountability of actions performed on the system and also helps to minimize direct attack attempts on root's password.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_disable_root_login

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 3, 5
cjis	5.5.6
cobit5	APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10
cui	3.1.1, 3.1.5
disa	CCI-000366, CCI-004045
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	AC-6(2), AC-17(a), IA-2, IA-2(5), CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3
ospp	FAU_GEN.1
pcidss	Req-2.2.4
os-srg	SRG-OS-000109-GPOS-00056, SRG-OS-000480-GPOS-00227
app-srg-ctr	SRG-APP-000148-CTR-000335, SRG-APP-000190-CTR-000500
anssi	R33
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*PermitRootLogin\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "PermitRootLogin no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6(2)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-2
  - NIST-800-53-IA-2(5)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_root_login

- name: Disable SSH Root Login
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PermitRootLogin\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PermitRootLogin\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PermitRootLogin\s+
      line: PermitRootLogin no
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.1
  - NIST-800-171-3.1.5
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6(2)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - NIST-800-53-IA-2
  - NIST-800-53-IA-2(5)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_disable_root_login

Rule Do Not Allow SSH Environment Options [ref]

Ensure that users are not able to override environment variables of the SSH daemon.
The default SSH configuration disables environment processing. The appropriate configuration is used if no value is set for PermitUserEnvironment.
To explicitly disable Environment options, add or correct the following /etc/ssh/sshd_config:

PermitUserEnvironment no

Rationale:

SSH environment options potentially allow users to bypass access restriction in some configurations.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_do_not_permit_user_env

References:

cis-csc	11, 3, 9
cjis	5.5.6
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05
cui	3.1.12
disa	CCI-000366
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3
isa-62443-2013	SR 7.6
iso27001-2013	A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4
nist	AC-17(a), CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.IP-1
pcidss	Req-2.2.4
os-srg	SRG-OS-000480-GPOS-00229
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*PermitUserEnvironment\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "PermitUserEnvironment no" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_do_not_permit_user_env

- name: Do Not Allow SSH Environment Options
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PermitUserEnvironment\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PermitUserEnvironment\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PermitUserEnvironment\s+
      line: PermitUserEnvironment no
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_do_not_permit_user_env

Rule Enable Use of Strict Mode Checking [ref]

SSHs StrictModes option checks file and ownership permissions in the user's home directory .ssh folder before accepting login. If world- writable permissions are found, logon is rejected.
The default SSH configuration has StrictModes enabled. The appropriate configuration is used if no value is set for StrictModes.
To explicitly enable StrictModes in SSH, add or correct the following line in /etc/ssh/sshd_config:

StrictModes yes

Rationale:

If other users have access to modify user-specific SSH configuration files, they may be able to log into the system as another user.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_enable_strictmodes

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.1.12
disa	CCI-000366
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	AC-6, AC-17(a), CM-6(a)
nist-csf	PR.AC-4, PR.DS-5
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*StrictModes\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "StrictModes yes" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(a)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_enable_strictmodes

- name: Enable Use of Strict Mode Checking
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*StrictModes\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*StrictModes\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*StrictModes\s+
      line: StrictModes yes
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(a)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_enable_strictmodes

Rule Enable SSH Warning Banner [ref]

To enable the warning banner and ensure it is consistent across the system, add or correct the following line in /etc/ssh/sshd_config:

Banner /etc/issue

Another section contains information on how to create an appropriate system-wide warning banner.

Rationale:

The warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers. Alternatively, systems whose ownership should not be obvious should ensure usage of a banner that does not provide easy attribution.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_enable_warning_banner

References:

cis-csc	1, 12, 15, 16
cjis	5.5.6
cobit5	DSS05.04, DSS05.10, DSS06.10
cui	3.1.9
disa	CCI-001387, CCI-001384, CCI-000048, CCI-001386, CCI-001388, CCI-001385
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nist	AC-8(a), AC-8(c), AC-17(a), CM-6(a)
nist-csf	PR.AC-7
ospp	FTA_TAB.1
pcidss	Req-2.2.4
os-srg	SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*Banner\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "Banner /etc/issue" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.9
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-8(a)
  - NIST-800-53-AC-8(c)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-2.2.4
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_enable_warning_banner

- name: Enable SSH Warning Banner
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*Banner\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*Banner\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*Banner\s+
      line: Banner /etc/issue
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.5.6
  - NIST-800-171-3.1.9
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-8(a)
  - NIST-800-53-AC-8(c)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-2.2.4
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_enable_warning_banner

Rule Enable Encrypted X11 Forwarding [ref]

By default, remote X11 connections are not encrypted when initiated by users. SSH has the capability to encrypt remote X11 connections when SSH's X11Forwarding option is enabled.

To enable X11 Forwarding, add or correct the following line in /etc/ssh/sshd_config:

X11Forwarding yes

Rationale:

Non-encrypted X displays allow an attacker to capture keystrokes and to execute commands remotely.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_sshd_enable_x11_forwarding

References:

cis-csc	1, 11, 12, 13, 15, 16, 18, 20, 3, 4, 6, 9
cobit5	BAI03.08, BAI07.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS03.01
cui	3.1.13
disa	CCI-000366
isa-62443-2009	4.3.4.3.2, 4.3.4.3.3, 4.4.3.3
isa-62443-2013	SR 7.6
iso27001-2013	A.12.1.1, A.12.1.2, A.12.1.4, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.14.2.2, A.14.2.3, A.14.2.4
nerc-cip	CIP-007-3 R7.1
nist	CM-6(a), AC-17(a), AC-17(2)
nist-csf	DE.AE-1, PR.DS-7, PR.IP-1
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*X11Forwarding\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "X11Forwarding yes" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy
  - sshd_enable_x11_forwarding

- name: Enable Encrypted X11 Forwarding
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*X11Forwarding\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*X11Forwarding\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*X11Forwarding\s+
      line: X11Forwarding yes
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-53-AC-17(2)
  - NIST-800-53-AC-17(a)
  - NIST-800-53-CM-6(a)
  - high_severity
  - low_complexity
  - low_disruption
  - no_reboot_needed
  - restrict_strategy
  - sshd_enable_x11_forwarding

Rule Enable SSH Print Last Log [ref]

Ensure that SSH will display the date and time of the last successful account logon.
The default SSH configuration enables print of the date and time of the last login. The appropriate configuration is used if no value is set for PrintLastLog.
To explicitly enable LastLog in SSH, add or correct the following line in /etc/ssh/sshd_config:

PrintLastLog yes

Rationale:

Providing users feedback on when account accesses last occurred facilitates user recognition and reporting of unauthorized account use.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_print_last_log

References:

cis-csc	1, 12, 15, 16
cobit5	DSS05.04, DSS05.10, DSS06.10
disa	CCI-000366
isa-62443-2009	4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9
iso27001-2013	A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3
nist	AC-9, AC-9(1)
nist-csf	PR.AC-7
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*PrintLastLog\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "PrintLastLog yes" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-9
  - NIST-800-53-AC-9(1)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_print_last_log

- name: Enable SSH Print Last Log
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PrintLastLog\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PrintLastLog\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*PrintLastLog\s+
      line: PrintLastLog yes
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-9
  - NIST-800-53-AC-9(1)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_print_last_log

Rule Enable Use of Privilege Separation [ref]

When enabled, SSH will create an unprivileged child process that has the privilege of the authenticated user. To enable privilege separation in SSH, add or correct the following line in the /etc/ssh/sshd_config file:

UsePrivilegeSeparation sandbox

Rationale:

SSH daemon privilege separation causes the SSH process to drop root privileges when not needed which would decrease the impact of software vulnerabilities in the unprivileged section.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sshd_use_priv_separation

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.1.12
disa	CCI-000366
hipaa	164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-6(a), AC-17(a), AC-6
nist-csf	PR.AC-4, PR.DS-5
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

var_sshd_priv_separation='sandbox'



if [ -e "/etc/ssh/sshd_config" ] ; then
    
    LC_ALL=C sed -i "/^\s*UsePrivilegeSeparation\s\+/Id" "/etc/ssh/sshd_config"
else
    touch "/etc/ssh/sshd_config"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/ssh/sshd_config"

cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
# Insert at the beginning of the file
printf '%s\n' "UsePrivilegeSeparation $var_sshd_priv_separation" > "/etc/ssh/sshd_config"
cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
# Clean up after ourselves.
rm "/etc/ssh/sshd_config.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(a)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_use_priv_separation
- name: XCCDF Value var_sshd_priv_separation # promote to variable
  set_fact:
    var_sshd_priv_separation: !!str sandbox
  tags:
    - always

- name: Enable Use of Privilege Separation
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*UsePrivilegeSeparation\s+
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*UsePrivilegeSeparation\s+
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/ssh/sshd_config
    lineinfile:
      path: /etc/ssh/sshd_config
      create: true
      regexp: (?i)(?i)^\s*UsePrivilegeSeparation\s+
      line: UsePrivilegeSeparation {{ var_sshd_priv_separation }}
      state: present
      insertbefore: BOF
      validate: /usr/sbin/sshd -t -f %s
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.12
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(a)
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sshd_use_priv_separation

Rule Install the OpenSSH Server Package [ref]

The openssh-server package should be installed. The openssh-server package can be installed with the following command:

$ sudo yum install openssh-server

Rationale:

Without protection of the transmitted information, confidentiality, and integrity may be compromised because unprotected communications can be intercepted and either read or altered.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_openssh-server_installed

References:

cis-csc	13, 14
cobit5	APO01.06, DSS05.02, DSS05.04, DSS05.07, DSS06.02, DSS06.06
disa	CCI-002420, CCI-002421, CCI-002418, CCI-002422
isa-62443-2013	SR 3.1, SR 3.8, SR 4.1, SR 4.2, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a)
nist-csf	PR.DS-2, PR.DS-5
ospp	FIA_UAU.5, FTP_ITC_EXT.1, FCS_SSH_EXT.1, FCS_SSHS_EXT.1
os-srg	SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "openssh-server" ; then
    yum install -y "openssh-server"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[[packages]]
name = "openssh-server"
version = "*"

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_openssh-server_installed

- name: Ensure openssh-server is installed
  package:
    name: openssh-server
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_openssh-server_installed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable


package --add=openssh-server

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include install_openssh-server

class install_openssh-server {
  package { 'openssh-server':
    ensure => 'installed',
  }
}

Rule Enable the OpenSSH Service [ref]

The SSH server service, sshd, is commonly needed. The sshd service can be enabled with the following command:

$ sudo systemctl enable sshd.service

Rationale:

Without protection of the transmitted information, confidentiality, and integrity may be compromised because unprotected communications can be intercepted and either read or altered.

This checklist item applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, etc). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_sshd_enabled

References:

cis-csc	13, 14
cobit5	APO01.06, DSS05.02, DSS05.04, DSS05.07, DSS06.02, DSS06.06
cui	3.1.13, 3.5.4, 3.13.8
disa	CCI-002420, CCI-002421, CCI-002418, CCI-002422
isa-62443-2013	SR 3.1, SR 3.8, SR 4.1, SR 4.2, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	CM-6(a), SC-8, SC-8(1), SC-8(2), SC-8(3), SC-8(4)
nist-csf	PR.DS-2, PR.DS-5
os-srg	SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'sshd.service'
"$SYSTEMCTL_EXEC" start 'sshd.service'
"$SYSTEMCTL_EXEC" enable 'sshd.service'

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
enabled = ["sshd"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.13.8
  - NIST-800-171-3.5.4
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-8
  - NIST-800-53-SC-8(1)
  - NIST-800-53-SC-8(2)
  - NIST-800-53-SC-8(3)
  - NIST-800-53-SC-8(4)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_sshd_enabled

- name: Enable the OpenSSH Service - Enable service sshd
  block:

  - name: Gather the package facts
    package_facts:
      manager: auto

  - name: Enable the OpenSSH Service - Enable Service sshd
    ansible.builtin.systemd:
      name: sshd
      enabled: true
      state: started
      masked: false
    when:
    - '"openssh-server" in ansible_facts.packages'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.13.8
  - NIST-800-171-3.5.4
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-8
  - NIST-800-53-SC-8(1)
  - NIST-800-53-SC-8(2)
  - NIST-800-53-SC-8(3)
  - NIST-800-53-SC-8(4)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_sshd_enabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include enable_sshd

class enable_sshd {
  service {'sshd':
    enable => true,
    ensure => 'running',
  }
}

Rule Verify Permissions on SSH Server Private *_key Key Files [ref]

SSH server private keys - files that match the /etc/ssh/*_key glob, have to have restricted permissions. If those files are owned by the root user and the root group, they have to have the 0600 permission or stricter.

Warning: Remediation is not possible at bootable container build time because SSH host keys are generated post-deployment.

Rationale:

If an unauthorized user obtains the private SSH host key file, the host could be impersonated.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permissions_sshd_private_key

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.1.13, 3.13.10
disa	CCI-000366
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	AC-17(a), CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.DS-5
pcidss	Req-2.2.4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R50
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

for keyfile in /etc/ssh/*_key; do
    test -f "$keyfile" || continue
    if test root:root = "$(stat -c "%U:%G" "$keyfile")"; then
    
	chmod u-xs,g-xwrs,o-xwrt "$keyfile"
    
    
    else
        echo "Key-like file '$keyfile' is owned by an unexpected user:group combination"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.13.10
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_permissions_sshd_private_key
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Find root:root-owned keys
  ansible.builtin.command: find -H /etc/ssh/ -maxdepth 1 -user root -regex ".*_key$"
    -type f -group root -perm /u+xs,g+xwrs,o+xwrt
  register: root_owned_keys
  changed_when: false
  failed_when: false
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.13.10
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_permissions_sshd_private_key
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set permissions for root:root-owned keys
  ansible.builtin.file:
    path: '{{ item }}'
    mode: u-xs,g-xwrs,o-xwrt
    state: file
  with_items:
  - '{{ root_owned_keys.stdout_lines }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.13.10
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_permissions_sshd_private_key
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Puppet snippet ⇲

include ssh_private_key_perms

class ssh_private_key_perms {
  exec { 'sshd_priv_key':
    command => "chmod 0640 /etc/ssh/*_key",
    path    => '/bin:/usr/bin'
  }
}

Rule Verify Permissions on SSH Server Public *.pub Key Files [ref]

To properly set the permissions of /etc/ssh/*.pub, run the command:

$ sudo chmod 0644 /etc/ssh/*.pub

Warning: Remediation is not possible at bootable container build time because SSH host keys are generated post-deployment.

Rationale:

If a public host key file is modified by an unauthorized user, the SSH service may be compromised.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permissions_sshd_pub_key

References:

cis-csc	12, 13, 14, 15, 16, 18, 3, 5
cobit5	APO01.06, DSS05.04, DSS05.07, DSS06.02
cui	3.1.13, 3.13.10
disa	CCI-000366
isa-62443-2009	4.3.3.7.3
isa-62443-2013	SR 2.1, SR 5.2
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	AC-17(a), CM-6(a), AC-6(1)
nist-csf	PR.AC-4, PR.DS-5
pcidss	Req-2.2.4
os-srg	SRG-OS-000480-GPOS-00227
anssi	R50
pcidss4	2.2.6, 2.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

find -L /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xws,o+xwt  -type f -regextype posix-extended -regex '^.*\.pub$' -exec chmod u-xs,g-xws,o-xwt {} \;

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.13.10
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_permissions_sshd_pub_key
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Find /etc/ssh/ file(s)
  command: find -H /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xws,o+xwt  -type f -regextype
    posix-extended -regex "^.*\.pub$"
  register: files_found
  changed_when: false
  failed_when: false
  check_mode: false
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.13.10
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_permissions_sshd_pub_key
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set permissions for /etc/ssh/ file(s)
  file:
    path: '{{ item }}'
    mode: u-xs,g-xws,o-xwt
    state: file
  with_items:
  - '{{ files_found.stdout_lines }}'
  when: '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.13
  - NIST-800-171-3.13.10
  - NIST-800-53-AC-17(a)
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-2.2.4
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_permissions_sshd_pub_key
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Puppet snippet ⇲

include ssh_public_key_perms

class ssh_public_key_perms {
  exec { 'sshd_pub_key':
    command => "chmod 0644 /etc/ssh/*.pub",
    path    => '/bin:/usr/bin'
  }
}

Group System Security Services Daemon Group contains 5 rules

[ref] The System Security Services Daemon (SSSD) is a system daemon that provides access to different identity and authentication providers such as Red Hat's IdM, Microsoft's AD, openLDAP, MIT Kerberos, etc. It uses a common framework that can provide caching and offline support to systems utilizing SSSD. SSSD using caching to reduce load on authentication servers permit offline authentication as well as store extended user data.

For more information, see

Rule Configure PAM in SSSD Services [ref]

SSSD should be configured to run SSSD pam services. To configure SSSD to known SSH hosts, add pam to services under the [sssd] section in /etc/sssd/sssd.conf. For example:

[sssd]
services = sudo, autofs, pam

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sssd_enable_pam_services

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-004046, CCI-001953, CCI-001954
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	IA-2(1), CM-6(a)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000375-GPOS-00160, SRG-OS-000376-GPOS-00161, SRG-OS-000377-GPOS-00162

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q sssd-common; then

# sssd configuration files must be created with 600 permissions if they don't exist
# otherwise the sssd module fails to start
OLD_UMASK=$(umask)
umask u=rw,go=

SSSD_CONF="/etc/sssd/sssd.conf"
SSSD_CONF_DIR="/etc/sssd/conf.d/*.conf"

if [ ! -f "$SSSD_CONF" ] && [ ! -f "$SSSD_CONF_DIR" ]; then
    mkdir -p /etc/sssd
    touch "$SSSD_CONF"
fi

# Flag to check if there is already services with pam
service_already_exist=false
for f in $SSSD_CONF $SSSD_CONF_DIR; do
	if [ ! -e "$f" ]; then
		continue
	fi
	# finds all services entries under [sssd] configuration category, get a unique list so it doesn't add redundant fix
	services_list=$( awk '/^\s*\[/{f=0} /^\s*\[sssd\]/{f=1}f' $f | grep -P '^services[ \t]*=' | uniq )
    if [ -z "$services_list" ]; then
        continue
    fi

	while IFS= read -r services; do
		if [[ ! $services =~ "pam" ]]; then
			sed -i "s/$services$/&, pam/" $f
		fi
        # Either pam service was already there or got added now
        service_already_exist=true
	done <<< "$services_list"

done

# If there was no service in [sssd], add it to first config
if [ "$service_already_exist" = false ]; then
    for f in $SSSD_CONF $SSSD_CONF_DIR; do
        cat << EOF >> "$f"
[sssd]
services = pam
EOF
        break
    done
fi

umask $OLD_UMASK

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_pam_services

- name: Configure PAM in SSSD Services - Find all the conf files inside the /etc/sssd/conf.d/
    directory
  ansible.builtin.find:
    paths:
    - /etc/sssd/conf.d/
    patterns: '*.conf'
  register: sssd_conf_d_files
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_pam_services

- name: Configure PAM in SSSD Services - Modify lines in files in the /etc/sssd/conf.d/
    directory
  ansible.builtin.replace:
    path: '{{ item }}'
    regexp: ^(\s*\[sssd\].*(?:\n\s*[^[\s].*)*\n\s*services\s*=(?!.*\bpam\b).*)$
    replace: \1,pam
  with_items: '{{ sssd_conf_d_files.files | map(attribute=''path'') }}'
  register: modify_lines_sssd_conf_d_files
  when:
  - '"sssd-common" in ansible_facts.packages'
  - sssd_conf_d_files.matched is defined and sssd_conf_d_files.matched >= 1
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_pam_services

- name: Configure PAM in SSSD Services - Find /etc/sssd/sssd.conf
  ansible.builtin.stat:
    path: /etc/sssd/sssd.conf
  register: sssd_conf_file
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_pam_services

- name: Configure PAM in SSSD Services - Modify lines in /etc/sssd/sssd.conf
  ansible.builtin.replace:
    path: /etc/sssd/sssd.conf
    regexp: ^(\s*\[sssd\].*(?:\n\s*[^[\s].*)*\n\s*services\s*=(?!.*\bpam\b).*)$
    replace: \1,pam
  register: modify_lines_sssd_conf_file
  when:
  - '"sssd-common" in ansible_facts.packages'
  - sssd_conf_file.stat.exists
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_pam_services

- name: Configure PAM in SSSD Services - Find services key in /etc/sssd/sssd.conf
  ansible.builtin.replace:
    path: /etc/sssd/sssd.conf
    regexp: ^\s*\[sssd\][^\[\]]*?(?:\n(?!\[)[^\n]*?services\s*=)+
    replace: ''
  changed_when: false
  check_mode: true
  register: sssd_conf_file_services
  when:
  - '"sssd-common" in ansible_facts.packages'
  - sssd_conf_file.stat.exists
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_pam_services

- name: Configure PAM in SSSD Services - Insert entry to /etc/sssd/sssd.conf
  ini_file:
    path: /etc/sssd/sssd.conf
    section: sssd
    option: services
    value: pam
  when:
  - '"sssd-common" in ansible_facts.packages'
  - not modify_lines_sssd_conf_d_files.changed
  - not modify_lines_sssd_conf_file.changed
  - (sssd_conf_file_services.msg is defined and "replacements" not in sssd_conf_file_services.msg)
    or not sssd_conf_file.stat.exists
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-2(1)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_pam_services

Rule Enable Smartcards in SSSD [ref]

SSSD should be configured to authenticate access to the system using smart cards. To enable smart cards in SSSD, set pam_cert_auth to True under the [pam] section in /etc/sssd/sssd.conf. For example:

[pam]
pam_cert_auth = True

Rationale:

Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.

Multi-Factor Authentication (MFA) solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD Common Access Card.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sssd_enable_smartcards

References:

disa	CCI-000765, CCI-004047, CCI-004046
ism	0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561
pcidss	Req-8.3
os-srg	SRG-OS-000375-GPOS-00160, SRG-OS-000105-GPOS-00052, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q sssd-common; then

# sssd configuration files must be created with 600 permissions if they don't exist
# otherwise the sssd module fails to start
OLD_UMASK=$(umask)
umask u=rw,go=

found=false

# set value in all files if they contain section or key
for f in $(echo -n "/etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf"); do
    if [ ! -e "$f" ]; then
        continue
    fi

    # find key in section and change value
    if grep -qzosP "[[:space:]]*\[pam\]([^\n\[]*\n+)+?[[:space:]]*pam_cert_auth" "$f"; then

            sed -i "s/pam_cert_auth[^(\n)]*/pam_cert_auth=True/" "$f"

            found=true

    # find section and add key = value to it
    elif grep -qs "[[:space:]]*\[pam\]" "$f"; then

            sed -i "/[[:space:]]*\[pam\]/a pam_cert_auth=True" "$f"

            found=true
    fi
done

# if section not in any file, append section with key = value to FIRST file in files parameter
if ! $found ; then
    file=$(echo "/etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf" | cut -f1 -d ' ')
    mkdir -p "$(dirname "$file")"

    echo -e "[pam]\npam_cert_auth=True" >> "$file"

fi

umask $OLD_UMASK

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSS-Req-8.3
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

- name: Test for domain group
  command: grep '^\s*\[domain\/[^]]*]' /etc/sssd/sssd.conf
  register: test_grep_domain
  failed_when: false
  changed_when: false
  check_mode: false
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - PCI-DSS-Req-8.3
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

- name: Add default domain group (if no domain there)
  ini_file:
    path: /etc/sssd/sssd.conf
    section: '{{ item.section }}'
    option: '{{ item.option }}'
    value: '{{ item.value }}'
    create: true
    mode: 384
  with_items:
  - section: sssd
    option: domains
    value: default
  - section: domain/default
    option: id_provider
    value: files
  when:
  - '"sssd-common" in ansible_facts.packages'
  - test_grep_domain.stdout is defined
  - test_grep_domain.stdout | length < 1
  tags:
  - PCI-DSS-Req-8.3
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

- name: Enable Smartcards in SSSD
  ini_file:
    dest: /etc/sssd/sssd.conf
    section: pam
    option: pam_cert_auth
    value: 'True'
    create: true
    mode: 384
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - PCI-DSS-Req-8.3
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

- name: Find all the conf files inside /etc/sssd/conf.d/
  find:
    paths: /etc/sssd/conf.d/
    patterns: '*.conf'
  register: sssd_conf_d_files
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - PCI-DSS-Req-8.3
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

- name: Fix pam_cert_auth configuration in /etc/sssd/conf.d/
  ansible.builtin.replace:
    path: '{{ item.path }}'
    regexp: '[^#]*pam_cert_auth.*'
    replace: pam_cert_auth = True
  with_items: '{{ sssd_conf_d_files.files }}'
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - PCI-DSS-Req-8.3
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_enable_smartcards

Rule Configure SSSD's Memory Cache to Expire [ref]

SSSD's memory cache should be configured to set to expire records after 300 seconds. To configure SSSD to expire memory cache, set memcache_timeout to 300 under the [nss] section in /etc/sssd/sssd.conf. For example:

[nss]
memcache_timeout = 300

Rationale:

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sssd_memcache_timeout

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-002007
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-6(a), IA-5(13)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000383-GPOS-00166

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q sssd-common; then

var_sssd_memcache_timeout='300'


# sssd configuration files must be created with 600 permissions if they don't exist
# otherwise the sssd module fails to start
OLD_UMASK=$(umask)
umask u=rw,go=

found=false

# set value in all files if they contain section or key
for f in $(echo -n "/etc/sssd/sssd.conf"); do
    if [ ! -e "$f" ]; then
        continue
    fi

    # find key in section and change value
    if grep -qzosP "[[:space:]]*\[nss\]([^\n\[]*\n+)+?[[:space:]]*memcache_timeout" "$f"; then

            sed -i "s/memcache_timeout[^(\n)]*/memcache_timeout=$var_sssd_memcache_timeout/" "$f"

            found=true

    # find section and add key = value to it
    elif grep -qs "[[:space:]]*\[nss\]" "$f"; then

            sed -i "/[[:space:]]*\[nss\]/a memcache_timeout=$var_sssd_memcache_timeout" "$f"

            found=true
    fi
done

# if section not in any file, append section with key = value to FIRST file in files parameter
if ! $found ; then
    file=$(echo "/etc/sssd/sssd.conf" | cut -f1 -d ' ')
    mkdir -p "$(dirname "$file")"

    echo -e "[nss]\nmemcache_timeout=$var_sssd_memcache_timeout" >> "$file"

fi

umask $OLD_UMASK

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	unknown

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_memcache_timeout
  - unknown_strategy
- name: XCCDF Value var_sssd_memcache_timeout # promote to variable
  set_fact:
    var_sssd_memcache_timeout: !!str 300
  tags:
    - always

- name: Test for domain group
  command: grep '\s*\[domain\/[^]]*]' /etc/sssd/sssd.conf
  register: test_grep_domain
  failed_when: false
  changed_when: false
  check_mode: false
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_memcache_timeout
  - unknown_strategy

- name: Add default domain group (if no domain there)
  ini_file:
    path: /etc/sssd/sssd.conf
    section: '{{ item.section }}'
    option: '{{ item.option }}'
    value: '{{ item.value }}'
    create: true
    mode: 384
  with_items:
  - section: sssd
    option: domains
    value: default
  - section: domain/default
    option: id_provider
    value: files
  when:
  - '"sssd-common" in ansible_facts.packages'
  - test_grep_domain.stdout is defined
  - test_grep_domain.stdout | length < 1
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_memcache_timeout
  - unknown_strategy

- name: Configure SSSD's Memory Cache to Expire
  ini_file:
    dest: /etc/sssd/sssd.conf
    section: nss
    option: memcache_timeout
    value: '{{ var_sssd_memcache_timeout }}'
    create: true
    mode: 384
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_memcache_timeout
  - unknown_strategy

Rule Configure SSSD to Expire Offline Credentials [ref]

SSSD should be configured to expire offline credentials after 1 day. To configure SSSD to expire offline credentials, set offline_credentials_expiration to 1 under the [pam] section in /etc/sssd/sssd.conf. For example:

[pam]
offline_credentials_expiration = 1

Rationale:

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sssd_offline_cred_expiration

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-002007
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-6(a), IA-5(13)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000383-GPOS-00166

Remediation Shell script ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q sssd-common; then

# sssd configuration files must be created with 600 permissions if they don't exist
# otherwise the sssd module fails to start
OLD_UMASK=$(umask)
umask u=rw,go=

found=false

# set value in all files if they contain section or key
for f in $(echo -n "/etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf"); do
    if [ ! -e "$f" ]; then
        continue
    fi

    # find key in section and change value
    if grep -qzosP "[[:space:]]*\[pam\]([^\n\[]*\n+)+?[[:space:]]*offline_credentials_expiration" "$f"; then

            sed -i "s/offline_credentials_expiration[^(\n)]*/offline_credentials_expiration=1/" "$f"

            found=true

    # find section and add key = value to it
    elif grep -qs "[[:space:]]*\[pam\]" "$f"; then

            sed -i "/[[:space:]]*\[pam\]/a offline_credentials_expiration=1" "$f"

            found=true
    fi
done

# if section not in any file, append section with key = value to FIRST file in files parameter
if ! $found ; then
    file=$(echo "/etc/sssd/sssd.conf /etc/sssd/conf.d/*.conf" | cut -f1 -d ' ')
    mkdir -p "$(dirname "$file")"

    echo -e "[pam]\noffline_credentials_expiration=1" >> "$file"

fi

umask $OLD_UMASK

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_offline_cred_expiration

- name: Test for domain group
  command: grep '\s*\[domain\/[^]]*]' /etc/sssd/sssd.conf
  register: test_grep_domain
  failed_when: false
  changed_when: false
  check_mode: false
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_offline_cred_expiration

- name: Add default domain group (if no domain there)
  ini_file:
    path: /etc/sssd/sssd.conf
    section: '{{ item.section }}'
    option: '{{ item.option }}'
    value: '{{ item.value }}'
    create: true
    mode: 384
  with_items:
  - section: sssd
    option: domains
    value: default
  - section: domain/default
    option: id_provider
    value: files
  when:
  - '"sssd-common" in ansible_facts.packages'
  - test_grep_domain.stdout is defined
  - test_grep_domain.stdout | length < 1
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_offline_cred_expiration

- name: Configure SSD to Expire Offline Credentials
  ini_file:
    dest: /etc/sssd/sssd.conf
    section: pam
    option: offline_credentials_expiration
    value: 1
    create: true
    mode: 384
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_offline_cred_expiration

- name: Find all the conf files inside /etc/sssd/conf.d/
  find:
    paths: /etc/sssd/conf.d/
    patterns: '*.conf'
  register: sssd_conf_d_files
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_offline_cred_expiration

- name: Fix offline_credentials_expiration configuration in /etc/sssd/conf.d/
  ansible.builtin.replace:
    path: '{{ item.path }}'
    regexp: '[^#]*offline_credentials_expiration.*'
    replace: offline_credentials_expiration = 1
  with_items: '{{ sssd_conf_d_files.files }}'
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - configure_strategy
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_offline_cred_expiration

Rule Configure SSSD to Expire SSH Known Hosts [ref]

SSSD should be configured to expire keys from known SSH hosts after 300 seconds. To configure SSSD to known SSH hosts, set ssh_known_hosts_timeout to 300 under the [ssh] section in /etc/sssd/sssd.conf. For example:

[ssh]
ssh_known_hosts_timeout = 300

Rationale:

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sssd_ssh_known_hosts_timeout

References:

cis-csc	1, 12, 15, 16, 5
cobit5	DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10
disa	CCI-002007
isa-62443-2009	4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1
iso27001-2013	A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3
nist	CM-6(a), IA-5(13)
nist-csf	PR.AC-1, PR.AC-6, PR.AC-7
os-srg	SRG-OS-000383-GPOS-00166

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q sssd-common; then

var_sssd_ssh_known_hosts_timeout='300'


# sssd configuration files must be created with 600 permissions if they don't exist
# otherwise the sssd module fails to start
OLD_UMASK=$(umask)
umask u=rw,go=

found=false

# set value in all files if they contain section or key
for f in $(echo -n "/etc/sssd/sssd.conf"); do
    if [ ! -e "$f" ]; then
        continue
    fi

    # find key in section and change value
    if grep -qzosP "[[:space:]]*\[ssh\]([^\n\[]*\n+)+?[[:space:]]*ssh_known_hosts_timeout" "$f"; then

            sed -i "s/ssh_known_hosts_timeout[^(\n)]*/ssh_known_hosts_timeout=$var_sssd_ssh_known_hosts_timeout/" "$f"

            found=true

    # find section and add key = value to it
    elif grep -qs "[[:space:]]*\[ssh\]" "$f"; then

            sed -i "/[[:space:]]*\[ssh\]/a ssh_known_hosts_timeout=$var_sssd_ssh_known_hosts_timeout" "$f"

            found=true
    fi
done

# if section not in any file, append section with key = value to FIRST file in files parameter
if ! $found ; then
    file=$(echo "/etc/sssd/sssd.conf" | cut -f1 -d ' ')
    mkdir -p "$(dirname "$file")"

    echo -e "[ssh]\nssh_known_hosts_timeout=$var_sssd_ssh_known_hosts_timeout" >> "$file"

fi

umask $OLD_UMASK

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	medium
Reboot:	false
Strategy:	unknown

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_ssh_known_hosts_timeout
  - unknown_strategy
- name: XCCDF Value var_sssd_ssh_known_hosts_timeout # promote to variable
  set_fact:
    var_sssd_ssh_known_hosts_timeout: !!str 300
  tags:
    - always

- name: Test for domain group
  command: grep '\s*\[domain\/[^]]*]' /etc/sssd/sssd.conf
  register: test_grep_domain
  failed_when: false
  changed_when: false
  check_mode: false
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_ssh_known_hosts_timeout
  - unknown_strategy

- name: Add default domain group (if no domain there)
  ini_file:
    path: /etc/sssd/sssd.conf
    section: '{{ item.section }}'
    option: '{{ item.option }}'
    value: '{{ item.value }}'
    create: true
    mode: 384
  with_items:
  - section: sssd
    option: domains
    value: default
  - section: domain/default
    option: id_provider
    value: files
  when:
  - '"sssd-common" in ansible_facts.packages'
  - test_grep_domain.stdout is defined
  - test_grep_domain.stdout | length < 1
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_ssh_known_hosts_timeout
  - unknown_strategy

- name: Configure SSSD to Expire SSH Known Hosts
  ini_file:
    dest: /etc/sssd/sssd.conf
    section: ssh
    option: ssh_known_hosts_timeout
    value: '{{ var_sssd_ssh_known_hosts_timeout }}'
    create: true
    mode: 384
  when: '"sssd-common" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(13)
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - sssd_ssh_known_hosts_timeout
  - unknown_strategy

Group X Window System Group contains 1 group and 1 rule

[ref] The X Window System implementation included with the system is called X.org.

Group Disable X Windows Group contains 1 rule

[ref] Unless there is a mission-critical reason for the system to run a graphical user interface, ensure X is not set to start automatically at boot and remove the X Windows software packages. There is usually no reason to run X Windows on a dedicated server system, as it increases the system's attack surface and consumes system resources. Administrators of server systems should instead login via SSH or on the text console.

Rule Remove the X Windows Package Group [ref]

By removing the xorg-x11-server-common package, the system no longer has X Windows installed. If X Windows is not installed then the system cannot boot into graphical user mode. This prevents the system from being accidentally or maliciously booted into a graphical.target mode. To do so, run the following command:

$ sudo yum groupremove base-x

$ sudo yum remove xorg-x11-server-common

Warning: The installation and use of a Graphical User Interface (GUI) increases your attack vector and decreases your overall security posture. Removing the package xorg-x11-server-common package will remove the graphical target which might bring your system to an inconsistent state requiring additional configuration to access the system again. If a GUI is an operational requirement, a tailored profile that removes this rule should used before continuing installation.

Rationale:

Unnecessary service packages must not be installed to decrease the attack surface of the system. X windows has a long history of security vulnerabilities and should not be installed unless approved and documented.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_xorg-x11-server-common_removed

References:

cis-csc	12, 15, 8
cobit5	APO13.01, DSS01.04, DSS05.02, DSS05.03
disa	CCI-000366
isa-62443-2009	4.3.3.6.6
isa-62443-2013	SR 1.13, SR 2.6, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.13.1.1, A.13.2.1, A.14.1.3, A.6.2.1, A.6.2.2
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-3, PR.PT-4
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


# CAUTION: This remediation script will remove xorg-x11-server-common
#	   from the system, and may remove any packages
#	   that depend on xorg-x11-server-common. Execute this
#	   remediation AFTER testing on a non-production
#	   system!

if rpm -q --quiet "xorg-x11-server-common" ; then
yum remove -y "xorg-x11-server-common"
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

- name: Ensure xorg-x11-server-common is removed
  package:
    name: xorg-x11-server-common
    state: absent
  tags:
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-7(a)
  - NIST-800-53-CM-7(b)
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_xorg-x11-server-common_removed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable


package --remove=xorg-x11-server-common

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	disable

include remove_xorg-x11-server-common

class remove_xorg-x11-server-common {
  package { 'xorg-x11-server-common':
    ensure => 'purged',
  }
}

Group System Accounting with auditd Group contains 10 groups and 87 rules

[ref] The audit service provides substantial capabilities for recording system activities. By default, the service audits about SELinux AVC denials and certain types of security-relevant events such as system logins, account modifications, and authentication events performed by programs such as sudo. Under its default configuration, auditd has modest disk space requirements, and should not noticeably impact system performance.

NOTE: The Linux Audit daemon auditd can be configured to use the augenrules program to read audit rules files (*.rules) located in /etc/audit/rules.d location and compile them to create the resulting form of the /etc/audit/audit.rules configuration file during the daemon startup (default configuration). Alternatively, the auditd daemon can use the auditctl utility to read audit rules from the /etc/audit/audit.rules configuration file during daemon startup, and load them into the kernel. The expected behavior is configured via the appropriate ExecStartPost directive setting in the /usr/lib/systemd/system/auditd.service configuration file. To instruct the auditd daemon to use the augenrules program to read audit rules (default configuration), use the following setting:

ExecStartPost=-/sbin/augenrules --load

in the /usr/lib/systemd/system/auditd.service configuration file. In order to instruct the auditd daemon to use the auditctl utility to read audit rules, use the following setting:

ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules

in the /usr/lib/systemd/system/auditd.service configuration file. Refer to [Service] section of the /usr/lib/systemd/system/auditd.service configuration file for further details.

Government networks often have substantial auditing requirements and auditd can be configured to meet these requirements. Examining some example audit records demonstrates how the Linux audit system satisfies common requirements. The following example from Red Hat Enterprise Linux 7 Documentation available at

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/selinux_users_and_administrators_guide/index#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages

shows the substantial amount of information captured in a two typical "raw" audit messages, followed by a breakdown of the most important fields. In this example the message is SELinux-related and reports an AVC denial (and the associated system call) that occurred when the Apache HTTP Server attempted to access the /var/www/html/file1 file (labeled with the samba_share_t type):

type=AVC msg=audit(1226874073.147:96): avc:  denied  { getattr } for pid=2465 comm="httpd"
path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)

msg=audit(1226874073.147:96)
- The number in parentheses is the unformatted time stamp (Epoch time) for the event, which can be converted to standard time by using the date command.
{ getattr }
- The item in braces indicates the permission that was denied. getattr indicates the source process was trying to read the target file's status information. This occurs before reading files. This action is denied due to the file being accessed having the wrong label. Commonly seen permissions include getattr, read, and write.
comm="httpd"
- The executable that launched the process. The full path of the executable is found in the exe= section of the system call (SYSCALL) message, which in this case, is exe="/usr/sbin/httpd".
path="/var/www/html/file1"
- The path to the object (target) the process attempted to access.
scontext="unconfined_u:system_r:httpd_t:s0"
- The SELinux context of the process that attempted the denied action. In this case, it is the SELinux context of the Apache HTTP Server, which is running in the httpd_t domain.
tcontext="unconfined_u:object_r:samba_share_t:s0"
- The SELinux context of the object (target) the process attempted to access. In this case, it is the SELinux context of file1. Note: the samba_share_t type is not accessible to processes running in the httpd_t domain.
From the system call (SYSCALL) message, two items are of interest:
- success=no: indicates whether the denial (AVC) was enforced or not. success=no indicates the system call was not successful (SELinux denied access). success=yes indicates the system call was successful - this can be seen for permissive domains or unconfined domains, such as initrc_t and kernel_t.
- exe="/usr/sbin/httpd": the full path to the executable that launched the process, which in this case, is exe="/usr/sbin/httpd".

Group Configure auditd Rules for Comprehensive Auditing Group contains 8 groups and 71 rules

[ref] The auditd program can perform comprehensive monitoring of system activity. This section describes recommended configuration settings for comprehensive auditing, but a full description of the auditing system's capabilities is beyond the scope of this guide. The mailing list linux-audit@redhat.com exists to facilitate community discussion of the auditing system.

The audit subsystem supports extensive collection of events, including:

Tracing of arbitrary system calls (identified by name or number) on entry or exit.
Filtering by PID, UID, call success, system call argument (with some limitations), etc.
Monitoring of specific files for modifications to the file's contents or metadata.

Auditing rules at startup are controlled by the file /etc/audit/audit.rules. Add rules to it to meet the auditing requirements for your organization. Each line in /etc/audit/audit.rules represents a series of arguments that can be passed to auditctl and can be individually tested during runtime. See documentation in

/usr/share/doc/audit-VERSION

and in the related man pages for more details.

If copying any example audit rulesets from /usr/share/doc/audit-VERSION, be sure to comment out the lines containing arch= which are not appropriate for your system's architecture. Then review and understand the following rules, ensuring rules are activated as needed for the appropriate architecture.

After reviewing all the rules, reading the following sections, and editing as needed, the new rules can be activated as follows:

$ sudo service auditd restart

Group Record Events that Modify the System's Discretionary Access Controls Group contains 13 rules

[ref] At a minimum, the audit system should collect file permission changes for all users and root. Note that the "-F arch=b32" lines should be present even on a 64 bit system. These commands identify system calls for auditing. Even if the system is 64 bit it can still execute 32 bit system calls. Additionally, these rules can be configured in a number of ways while still achieving the desired effect. An example of this is that the "-S" calls could be split up and placed on separate lines, however, this is less efficient. Add the following to /etc/audit/audit.rules:

-a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows:

-a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
    -a always,exit -F arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Rule Record Events that Modify the System's Discretionary Access Controls - chmod [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale:

The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chmod

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="chmod"
	KEY="perm_mod"
	SYSCALL_GROUPING="chmod fchmod fchmodat"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_chmod
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit chmod tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_chmod
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for chmod for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - chmod
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of chmod in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - chmod
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of chmod in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_chmod
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for chmod for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - chmod
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of chmod in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - chmod
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of chmod in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_chmod
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - chown [ref]

-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chown

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="chown"
	KEY="perm_mod"
	SYSCALL_GROUPING="chown fchown fchownat lchown"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_chown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit chown tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_chown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for chown for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - chown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of chown in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - chown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of chown in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_chown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for chown for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - chown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of chown in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - chown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of chown in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_chown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - fchmod [ref]

-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmod

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="fchmod"
	KEY="perm_mod"
	SYSCALL_GROUPING="chmod fchmod fchmodat"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchmod
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit fchmod tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchmod
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fchmod for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchmod
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of fchmod in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchmod
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of fchmod in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchmod
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fchmod for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchmod
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of fchmod in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchmod
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of fchmod in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchmod
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - fchmodat [ref]

-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmodat

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="fchmodat"
	KEY="perm_mod"
	SYSCALL_GROUPING="chmod fchmod fchmodat"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchmodat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit fchmodat tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchmodat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fchmodat for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchmodat
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of fchmodat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchmodat
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of fchmodat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchmodat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fchmodat for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchmodat
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of fchmodat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchmodat
      syscall_grouping:
      - chmod
      - fchmod
      - fchmodat

  - name: Check existence of fchmodat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchmodat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - fchown [ref]

-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchown

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="fchown"
	KEY="perm_mod"
	SYSCALL_GROUPING="chown fchown fchownat lchown"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit fchown tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fchown for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of fchown in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of fchown in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fchown for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of fchown in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of fchown in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - fchownat [ref]

-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchownat

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="fchownat"
	KEY="perm_mod"
	SYSCALL_GROUPING="chown fchown fchownat lchown"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchownat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit fchownat tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchownat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fchownat for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchownat
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of fchownat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchownat
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of fchownat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchownat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fchownat for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchownat
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of fchownat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fchownat
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of fchownat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fchownat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - fremovexattr [ref]

At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fremovexattr

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000064-GPOS-00033
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="fremovexattr"
	KEY="perm_mod"
	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fremovexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit fremovexattr tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fremovexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fremovexattr for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fremovexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of fremovexattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fremovexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of fremovexattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fremovexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fremovexattr for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fremovexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of fremovexattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fremovexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of fremovexattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fremovexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - fsetxattr [ref]

-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fsetxattr

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="fsetxattr"
	KEY="perm_mod"
	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fsetxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit fsetxattr tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fsetxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fsetxattr for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fsetxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of fsetxattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fsetxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of fsetxattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fsetxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for fsetxattr for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fsetxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of fsetxattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - fsetxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of fsetxattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_fsetxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - lchown [ref]

-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lchown

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="lchown"
	KEY="perm_mod"
	SYSCALL_GROUPING="chown fchown fchownat lchown"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lchown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit lchown tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lchown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for lchown for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lchown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of lchown in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lchown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of lchown in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lchown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for lchown for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lchown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of lchown in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lchown
      syscall_grouping:
      - chown
      - fchown
      - fchownat
      - lchown

  - name: Check existence of lchown in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lchown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - lremovexattr [ref]

At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lremovexattr

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="lremovexattr"
	KEY="perm_mod"
	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lremovexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit lremovexattr tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lremovexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for lremovexattr for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lremovexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of lremovexattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lremovexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of lremovexattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lremovexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for lremovexattr for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lremovexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of lremovexattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lremovexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of lremovexattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lremovexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - lsetxattr [ref]

-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lsetxattr

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="lsetxattr"
	KEY="perm_mod"
	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lsetxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit lsetxattr tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lsetxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for lsetxattr for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lsetxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of lsetxattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lsetxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of lsetxattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lsetxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for lsetxattr for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lsetxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of lsetxattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - lsetxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of lsetxattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_lsetxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - removexattr [ref]

At a minimum, the audit system should collect file permission changes for all users and root.

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_removexattr

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="removexattr"
	KEY="perm_mod"
	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_removexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit removexattr tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_removexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for removexattr for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - removexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of removexattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - removexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of removexattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_removexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for removexattr for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - removexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of removexattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - removexattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of removexattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_removexattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Discretionary Access Controls - setxattr [ref]

-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_setxattr

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000466-GPOS-00210, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203
app-srg-ctr	SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="setxattr"
	KEY="perm_mod"
	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_setxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit setxattr tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_setxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for setxattr for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - setxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of setxattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - setxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of setxattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_setxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for setxattr for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - setxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of setxattr in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - setxattr
      syscall_grouping:
      - fremovexattr
      - lremovexattr
      - removexattr
      - fsetxattr
      - lsetxattr
      - setxattr

  - name: Check existence of setxattr in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_dac_modification_setxattr
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Group Record Execution Attempts to Run SELinux Privileged Commands Group contains 5 rules

[ref] At a minimum, the audit system should collect the execution of SELinux privileged commands for all users and root.

Rule Record Any Attempts to Run chcon [ref]

At a minimum, the audit system should collect any execution attempt of the chcon command for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/chcon -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F path=/usr/bin/chcon -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_execution_chcon

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chcon"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_chcon
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/chcon
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/chcon -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chcon -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chcon -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/chcon -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/chcon -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chcon -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_chcon
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Record Any Attempts to Run restorecon [ref]

At a minimum, the audit system should collect any execution attempt of the restorecon command for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/restorecon -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F path=/usr/sbin/restorecon -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_execution_restorecon

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000392-GPOS-00172, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/restorecon"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_restorecon
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/sbin/restorecon
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/restorecon -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/restorecon -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/restorecon
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/restorecon -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/sbin/restorecon -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/restorecon
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_restorecon
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Record Any Attempts to Run semanage [ref]

At a minimum, the audit system should collect any execution attempt of the semanage command for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/semanage -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F path=/usr/sbin/semanage -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_execution_semanage

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/semanage"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_semanage
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/sbin/semanage
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/semanage -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/semanage -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/semanage -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/semanage -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/sbin/semanage -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/semanage -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_semanage
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Record Any Attempts to Run setfiles [ref]

At a minimum, the audit system should collect any execution attempt of the setfiles command for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/setfiles -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F path=/usr/sbin/setfiles -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_execution_setfiles

References:

disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/setfiles"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_setfiles
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/sbin/setfiles
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/setfiles -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/setfiles -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setfiles -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/setfiles -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/sbin/setfiles -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setfiles -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_setfiles
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Record Any Attempts to Run setsebool [ref]

At a minimum, the audit system should collect any execution attempt of the setsebool command for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/sbin/setsebool -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F path=/usr/sbin/setsebool -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_execution_setsebool

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/setsebool"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_setsebool
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/sbin/setsebool
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/setsebool -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/setsebool -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setsebool -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/setsebool -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/sbin/setsebool -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setsebool -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_execution_setsebool
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Group Record File Deletion Events by User Group contains 5 rules

[ref] At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete

Rule Ensure auditd Collects File Deletion Events by User - rename [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete

-a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_rename

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.7
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270
anssi	R73
pcidss4	10.2.1.7, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="rename"
	KEY="delete"
	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_rename
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit rename tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_rename
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for rename for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - rename
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of rename in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - rename
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of rename in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_rename
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for rename for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - rename
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of rename in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - rename
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of rename in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_rename
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Ensure auditd Collects File Deletion Events by User - renameat [ref]

-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete

-a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_renameat

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.7
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270
anssi	R73
pcidss4	10.2.1.7, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="renameat"
	KEY="delete"
	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_renameat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit renameat tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_renameat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for renameat for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - renameat
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of renameat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - renameat
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of renameat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_renameat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for renameat for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - renameat
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of renameat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - renameat
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of renameat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_renameat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Ensure auditd Collects File Deletion Events by User - rmdir [ref]

-a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete

-a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_rmdir

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.7
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270
anssi	R73
pcidss4	10.2.1.7, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="rmdir"
	KEY="delete"
	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_rmdir
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit rmdir tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_rmdir
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for rmdir for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - rmdir
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of rmdir in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - rmdir
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of rmdir in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_rmdir
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for rmdir for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - rmdir
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of rmdir in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - rmdir
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of rmdir in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_rmdir
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Ensure auditd Collects File Deletion Events by User - unlink [ref]

-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete

-a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_unlink

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.7
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270
anssi	R73
pcidss4	10.2.1.7, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="unlink"
	KEY="delete"
	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_unlink
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit unlink tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_unlink
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for unlink for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - unlink
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of unlink in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - unlink
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of unlink in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_unlink
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for unlink for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - unlink
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of unlink in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - unlink
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of unlink in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_unlink
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Ensure auditd Collects File Deletion Events by User - unlinkat [ref]

-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete

-a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_unlinkat

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.7
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270
anssi	R73
pcidss4	10.2.1.7, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="unlinkat"
	KEY="delete"
	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_unlinkat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit unlinkat tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_unlinkat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for unlinkat for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - unlinkat
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of unlinkat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - unlinkat
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of unlinkat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_unlinkat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for unlinkat for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - unlinkat
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of unlinkat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
    set_fact: audit_file="/etc/audit/rules.d/delete.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - unlinkat
      syscall_grouping:
      - unlink
      - unlinkat
      - rename
      - renameat
      - rmdir

  - name: Check existence of unlinkat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=delete
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_file_deletion_events_unlinkat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Group Record Unauthorized Access Attempts Events to Files (unsuccessful) Group contains 6 rules

[ref] At a minimum, the audit system should collect unauthorized file accesses for all users and root. Note that the "-F arch=b32" lines should be present even on a 64 bit system. These commands identify system calls for auditing. Even if the system is 64 bit it can still execute 32 bit system calls. Additionally, these rules can be configured in a number of ways while still achieving the desired effect. An example of this is that the "-S" calls could be split up and placed on separate lines, however, this is less efficient. Add the following to /etc/audit/audit.rules:

-a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows:

-a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Rule Record Unsuccessful Access Attempts to Files - creat [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_creat

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.4, Req-10.2.1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205
app-srg-ctr	SRG-APP-000495-CTR-001235
anssi	R73

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="creat"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EACCES"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EPERM"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_creat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit creat tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_creat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for creat EACCES for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - creat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of creat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - creat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of creat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_creat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for creat EACCES for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - creat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of creat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - creat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of creat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_creat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for creat EPERM for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - creat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of creat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - creat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of creat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_creat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for creat EPERM for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - creat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of creat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - creat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of creat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_creat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Unsuccessful Access Attempts to Files - ftruncate [ref]

-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_ftruncate

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.4, Req-10.2.1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205
app-srg-ctr	SRG-APP-000495-CTR-001235
anssi	R73

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="ftruncate"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EACCES"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EPERM"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_ftruncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit ftruncate tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_ftruncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for ftruncate EACCES for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - ftruncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of ftruncate in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - ftruncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of ftruncate in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_ftruncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for ftruncate EACCES for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - ftruncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of ftruncate in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - ftruncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of ftruncate in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_ftruncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for ftruncate EPERM for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - ftruncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of ftruncate in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - ftruncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of ftruncate in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_ftruncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for ftruncate EPERM for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - ftruncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of ftruncate in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - ftruncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of ftruncate in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_ftruncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Unsuccessful Access Attempts to Files - open [ref]

-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_open

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.4, Req-10.2.1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205
app-srg-ctr	SRG-APP-000495-CTR-001235
anssi	R73

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="open"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EACCES"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EPERM"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit open tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for open EACCES for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for open EACCES for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for open EPERM for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for open EPERM for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - not ( ansible_architecture == "aarch64" )
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Unsuccessful Access Attempts to Files - open_by_handle_at [ref]

-a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_open_by_handle_at

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.4, Req-10.2.1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205
app-srg-ctr	SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="open_by_handle_at"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EACCES"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EPERM"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open_by_handle_at
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit open_by_handle_at tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open_by_handle_at
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for open_by_handle_at EACCES for 32bit
    platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open_by_handle_at
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open_by_handle_at in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open_by_handle_at
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open_by_handle_at in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open_by_handle_at
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for open_by_handle_at EACCES for 64bit
    platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open_by_handle_at
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open_by_handle_at in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open_by_handle_at
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open_by_handle_at in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open_by_handle_at
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for open_by_handle_at EPERM for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open_by_handle_at
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open_by_handle_at in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open_by_handle_at
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open_by_handle_at in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open_by_handle_at
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for open_by_handle_at EPERM for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open_by_handle_at
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open_by_handle_at in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - open_by_handle_at
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of open_by_handle_at in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_open_by_handle_at
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Unsuccessful Access Attempts to Files - openat [ref]

-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_openat

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.4, Req-10.2.1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205
app-srg-ctr	SRG-APP-000495-CTR-001235
anssi	R73

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="openat"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EACCES"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EPERM"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_openat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit openat tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_openat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for openat EACCES for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - openat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of openat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - openat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of openat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_openat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for openat EACCES for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - openat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of openat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - openat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of openat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_openat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for openat EPERM for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - openat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of openat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - openat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of openat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_openat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for openat EPERM for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - openat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of openat in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - openat
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of openat in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_openat
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Unsuccessful Access Attempts to Files - truncate [ref]

-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

-a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
-a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Rationale:

Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_truncate

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.4, Req-10.2.1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205
app-srg-ctr	SRG-APP-000495-CTR-001235
anssi	R73

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL="truncate"
KEY="access"
SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EACCES"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F exit=-EPERM"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_truncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit truncate tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_truncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for truncate EACCES for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - truncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of truncate in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - truncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of truncate in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_truncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for truncate EACCES for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - truncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of truncate in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - truncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of truncate in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_truncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for truncate EPERM for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - truncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of truncate in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - truncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of truncate in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_truncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for truncate EPERM for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - truncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of truncate in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
    set_fact: audit_file="/etc/audit/rules.d/access.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - truncate
      syscall_grouping:
      - creat
      - ftruncate
      - truncate
      - open
      - openat
      - open_by_handle_at

  - name: Check existence of truncate in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
        -F auid>=1000 -F auid!=unset -F key=access
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.1
  - PCI-DSS-Req-10.2.4
  - audit_rules_unsuccessful_file_modification_truncate
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Group Record Information on Kernel Modules Loading and Unloading Group contains 3 rules

[ref] To capture kernel module loading and unloading events, use following lines, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S init_module,delete_module -F key=modules

Place to add the lines depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the lines to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the lines to file /etc/audit/audit.rules.

Rule Ensure auditd Collects Information on Kernel Module Unloading - delete_module [ref]

To capture kernel module unloading events, use following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S delete_module -F key=modules

Place to add the line depends on a way auditd daemon is configured. If it is configured to use the augenrules program (the default), add the line to a file with suffix .rules in the directory /etc/audit/rules.d. If the auditd daemon is configured to use the auditctl utility, add the line to file /etc/audit/audit.rules.

Rationale:

The removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_kernel_module_loading_delete

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.7
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000504-CTR-001280
anssi	R73

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
#       it's required on a 64-bit system to check also for the presence
#       of 32-bit's equivalent of the corresponding rule.
#       (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	
	AUID_FILTERS=""
	
	SYSCALL="delete_module"
	KEY="modules"
	SYSCALL_GROUPING="delete_module"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_delete
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set architecture for audit delete_module tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_delete
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Perform remediation of Audit rules for delete_module for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - delete_module
      syscall_grouping: []

  - name: Check existence of delete_module in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
    set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - delete_module
      syscall_grouping: []

  - name: Check existence of delete_module in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_delete
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Perform remediation of Audit rules for delete_module for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - delete_module
      syscall_grouping: []

  - name: Check existence of delete_module in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
    set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - delete_module
      syscall_grouping: []

  - name: Check existence of delete_module in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_delete
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Ensure auditd Collects Information on Kernel Module Loading and Unloading - finit_module [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S finit_module -F key=modules

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S finit_module -F key=modules

Rationale:

The addition/removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_kernel_module_loading_finit

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.7
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000504-CTR-001280
anssi	R73

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
#       it's required on a 64-bit system to check also for the presence
#       of 32-bit's equivalent of the corresponding rule.
#       (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	
	AUID_FILTERS=""
	
	SYSCALL="finit_module"
	KEY="modules"
	SYSCALL_GROUPING="init_module finit_module"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_finit
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set architecture for audit finit_module tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_finit
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Perform remediation of Audit rules for finit_module for x86 platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - finit_module
      syscall_grouping:
      - init_module
      - finit_module

  - name: Check existence of finit_module in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
    set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - finit_module
      syscall_grouping:
      - init_module
      - finit_module

  - name: Check existence of finit_module in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_finit
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Perform remediation of Audit rules for finit_module for x86_64 platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - finit_module
      syscall_grouping:
      - init_module
      - finit_module

  - name: Check existence of finit_module in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
    set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - finit_module
      syscall_grouping:
      - init_module
      - finit_module

  - name: Check existence of finit_module in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_finit
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Ensure auditd Collects Information on Kernel Module Loading - init_module [ref]

To capture kernel module loading events, use following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

-a always,exit -F arch=ARCH -S init_module -F key=modules

Rationale:

The addition of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_kernel_module_loading_init

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.7
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000504-CTR-001280
anssi	R73

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
# Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
#       it's required on a 64-bit system to check also for the presence
#       of 32-bit's equivalent of the corresponding rule.
#       (See `man 7 audit.rules` for details )
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	
	AUID_FILTERS=""
	
	SYSCALL="init_module"
	KEY="modules"
	SYSCALL_GROUPING="init_module finit_module"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_init
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set architecture for audit init_module tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_init
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Perform remediation of Audit rules for init_module for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - init_module
      syscall_grouping:
      - init_module
      - finit_module

  - name: Check existence of init_module in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
    set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - init_module
      syscall_grouping:
      - init_module
      - finit_module

  - name: Check existence of init_module in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_init
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Perform remediation of Audit rules for init_module for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - init_module
      syscall_grouping:
      - init_module
      - finit_module

  - name: Check existence of init_module in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
    set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - init_module
      syscall_grouping:
      - init_module
      - finit_module

  - name: Check existence of init_module in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=module-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - audit_rules_kernel_module_loading_init
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Group Record Attempts to Alter Logon and Logout Events Group contains 3 rules

[ref] The audit system already collects login information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d in order to watch for attempted manual edits of files involved in storing logon events:

-w /var/log/tallylog -p wa -k logins
-w /var/log/faillock -p wa -k logins
-w /var/log/lastlog -p wa -k logins

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to watch for unattempted manual edits of files involved in storing logon events:

-w /var/log/tallylog -p wa -k logins
-w /var/log/faillock -p wa -k logins
-w /var/log/lastlog -p wa -k logins

Rule Record Attempts to Alter Logon and Logout Events - faillock [ref]

The audit system already collects login information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d in order to watch for attempted manual edits of files involved in storing logon events:

-w /var/log/faillock -p wa -k logins

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to watch for unattempted manual edits of files involved in storing logon events:

-w /var/log/faillock -p wa -k logins

Rationale:

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_login_events_faillock

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.3
os-srg	SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218
app-srg-ctr	SRG-APP-000503-CTR-001275, SRG-APP-000506-CTR-001290
anssi	R73
pcidss4	10.2.1.3, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'


var_accounts_passwords_pam_faillock_dir='/var/log/faillock'

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+${var_accounts_passwords_pam_faillock_dir}" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir} $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir}$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w ${var_accounts_passwords_pam_faillock_dir} -p wa -k logins" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+${var_accounts_passwords_pam_faillock_dir}" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/logins.rules"
    # If the logins.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+${var_accounts_passwords_pam_faillock_dir}" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir} $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir}$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w ${var_accounts_passwords_pam_faillock_dir} -p wa -k logins" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_faillock
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
- name: XCCDF Value var_accounts_passwords_pam_faillock_dir # promote to variable
  set_fact:
    var_accounts_passwords_pam_faillock_dir: !!str /var/log/faillock
  tags:
    - always

- name: Check if watch rule for {{ var_accounts_passwords_pam_faillock_dir }} already
    exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+{{ var_accounts_passwords_pam_faillock_dir }}\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_faillock
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key logins
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)logins$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_faillock
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/logins.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_faillock
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_faillock
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for {{ var_accounts_passwords_pam_faillock_dir }} in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w {{ var_accounts_passwords_pam_faillock_dir }} -p wa -k logins
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_faillock
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for {{ var_accounts_passwords_pam_faillock_dir }} already
    exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+{{ var_accounts_passwords_pam_faillock_dir }}\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_faillock
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for {{ var_accounts_passwords_pam_faillock_dir }} in /etc/audit/audit.rules
  lineinfile:
    line: -w {{ var_accounts_passwords_pam_faillock_dir }} -p wa -k logins
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_faillock
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Attempts to Alter Logon and Logout Events - lastlog [ref]

-w /var/log/lastlog -p wa -k logins

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to watch for unattempted manual edits of files involved in storing logon events:

-w /var/log/lastlog -p wa -k logins

Rationale:

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_login_events_lastlog

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.3
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000470-GPOS-00214
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000503-CTR-001275, SRG-APP-000506-CTR-001290
anssi	R73
pcidss4	10.2.1.3, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'


# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/lastlog" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/logins.rules"
    # If the logins.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_lastlog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/log/lastlog already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/var/log/lastlog\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_lastlog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key logins
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)logins$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_lastlog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/logins.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_lastlog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_lastlog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/log/lastlog in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /var/log/lastlog -p wa -k logins
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_lastlog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/log/lastlog already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/var/log/lastlog\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_lastlog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/log/lastlog in /etc/audit/audit.rules
  lineinfile:
    line: -w /var/log/lastlog -p wa -k logins
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_lastlog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Attempts to Alter Logon and Logout Events - tallylog [ref]

-w /var/log/tallylog -p wa -k logins

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to watch for unattempted manual edits of files involved in storing logon events:

-w /var/log/tallylog -p wa -k logins

Rationale:

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_login_events_tallylog

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.3
os-srg	SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218
app-srg-ctr	SRG-APP-000503-CTR-001275
pcidss4	10.2.1.3, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'


# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/tallylog" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/logins.rules"
    # If the logins.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_tallylog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/log/tallylog already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/var/log/tallylog\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_tallylog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key logins
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)logins$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_tallylog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/logins.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_tallylog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_tallylog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/log/tallylog in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /var/log/tallylog -p wa -k logins
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_tallylog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/log/tallylog already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/var/log/tallylog\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_tallylog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/log/tallylog in /etc/audit/audit.rules
  lineinfile:
    line: -w /var/log/tallylog -p wa -k logins
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_login_events_tallylog
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Group Record Information on the Use of Privileged Commands Group contains 17 rules

[ref] At a minimum, the audit system should collect the execution of privileged commands for all users and root.

Rule Ensure auditd Collects Information on the Use of Privileged Commands [ref]

The audit system should collect information about usage of privileged commands for all users. These are commands with suid or sgid bits on and they are specially risky in local block device partitions not mounted with noexec and nosuid options. Therefore, these partitions should be first identified by the following command:

findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,) | grep -Pv "noexec|nosuid"

For all partitions listed by the previous command, it is necessary to search for setuid / setgid programs using the following command:

$ sudo find PARTITION -xdev -perm /6000 -type f 2>/dev/null

For each setuid / setgid program identified by the previous command, an audit rule must be present in the appropriate place using the following line structure:

-a always,exit -F path=PROG_PATH -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup, add the line to a file with suffix .rules in the /etc/audit/rules.d directory, replacing the PROG_PATH part with the full path of that setuid / setgid identified program. If the auditd daemon is configured to use the auditctl utility instead, add the line to the /etc/audit/audit.rules file, also replacing the PROG_PATH part with the full path of that setuid / setgid identified program.

Warning: This rule checks for multiple syscalls related to privileged commands. If needed to check specific privileged commands, other more specific rules should be considered. For example:

audit_rules_privileged_commands_su
audit_rules_privileged_commands_umount
audit_rules_privileged_commands_passwd

Warning: Note that OVAL check and Bash / Ansible remediation of this rule explicitly excludes file systems mounted at /proc directory and its subdirectories. It is a virtual file system and it doesn't contain executable applications. At the same time, interacting with this file system during check or remediation caused undesirable errors.

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern that can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.

Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO08.04, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.05, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-002234
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.5, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.3.4.5.9, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 3.9, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
ism	0582, 0584, 05885, 0586, 0846, 0957
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.1, A.16.1.2, A.16.1.3, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.3, A.6.2.1, A.6.2.2
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-2, DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, DE.DP-4, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, RS.CO-2
pcidss	Req-10.2.2
os-srg	SRG-OS-000327-GPOS-00127
anssi	R73

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""

FILTER_NODEV=$(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)
PARTITIONS=$(findmnt -n -l -k -it $FILTER_NODEV | grep -Pv "noexec|nosuid|/proc($|/.*$)" | awk '{ print $1 }')
for PARTITION in $PARTITIONS; do
  PRIV_CMDS=$(find "${PARTITION}" -xdev -perm /6000 -type f 2>/dev/null)
  for PRIV_CMD in $PRIV_CMDS; do
    OTHER_FILTERS="-F path=$PRIV_CMD -F perm=x"
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0600 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()


    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
  done
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - audit_rules_privileged_commands
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure auditd Collects Information on the Use of Privileged Commands - Set
    List of Mount Points Which Permits Execution of Privileged Commands
  ansible.builtin.set_fact:
    privileged_mount_points: '{{ (ansible_facts.mounts | rejectattr(''options'', ''search'',
      ''noexec|nosuid'') | rejectattr(''mount'', ''match'', ''/proc($|/.*$)'') | map(attribute=''mount'')
      | list ) }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - audit_rules_privileged_commands
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure auditd Collects Information on the Use of Privileged Commands - Search
    for Privileged Commands in Eligible Mount Points
  ansible.builtin.shell:
    cmd: find {{ item }} -xdev -perm /6000 -type f 2>/dev/null
  register: result_privileged_commands_search
  changed_when: false
  failed_when: false
  with_items: '{{ privileged_mount_points }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - audit_rules_privileged_commands
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure auditd Collects Information on the Use of Privileged Commands - Set
    List of Privileged Commands Found in Eligible Mount Points
  ansible.builtin.set_fact:
    privileged_commands: '{{ privileged_commands | default([]) + item.stdout_lines
      }}'
  loop: '{{ result_privileged_commands_search.results }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - item is not skipped
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - audit_rules_privileged_commands
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure auditd Collects Information on the Use of Privileged Commands - Privileged
    Commands are Present in the System
  block:

  - name: Ensure auditd Collects Information on the Use of Privileged Commands - Ensure
      Rules for All Privileged Commands in augenrules Format
    ansible.builtin.lineinfile:
      path: /etc/audit/rules.d/privileged.rules
      line: -a always,exit -F path={{ item }} -F perm=x -F auid>=1000 -F auid!=unset
        -F key=privileged
      regexp: ^.*path={{ item | regex_escape() }} .*$
      create: true
    with_items:
    - '{{ privileged_commands }}'

  - name: Ensure auditd Collects Information on the Use of Privileged Commands - Ensure
      Rules for All Privileged Commands in auditctl Format
    ansible.builtin.lineinfile:
      path: /etc/audit/audit.rules
      line: -a always,exit -F path={{ item }} -F perm=x -F auid>=1000 -F auid!=unset
        -F key=privileged
      regexp: ^.*path={{ item | regex_escape() }} .*$
      create: true
    with_items:
    - '{{ privileged_commands }}'

  - name: Ensure auditd Collects Information on the Use of Privileged Commands - Search
      for Duplicated Rules in Other Files
    ansible.builtin.find:
      paths: /etc/audit/rules.d
      recurse: false
      contains: ^-a always,exit -F path={{ item }} .*$
      patterns: '*.rules'
    with_items:
    - '{{ privileged_commands }}'
    register: result_augenrules_files

  - name: Ensure auditd Collects Information on the Use of Privileged Commands - Ensure
      Rules for Privileged Commands are Defined Only in One File
    ansible.builtin.lineinfile:
      path: '{{ item.1.path }}'
      regexp: ^-a always,exit -F path={{ item.0.item }} .*$
      state: absent
    with_subelements:
    - '{{ result_augenrules_files.results }}'
    - files
    when:
    - item.1.path != '/etc/audit/rules.d/privileged.rules'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - privileged_commands is defined
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - audit_rules_privileged_commands
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Ensure auditd Collects Information on the Use of Privileged Commands - chage [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F path=/usr/bin/chage -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/chage -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_chage

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chage"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_chage
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/chage
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/chage -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chage -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chage -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/chage -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/chage -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chage -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_chage
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - chsh [ref]

-a always,exit -F path=/usr/bin/chsh -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/chsh -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_chsh

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/chsh"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_chsh
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/chsh
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/chsh -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chsh -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chsh -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/chsh -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/chsh -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chsh -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_chsh
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - crontab [ref]

-a always,exit -F path=/usr/bin/crontab -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/crontab -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_crontab

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/crontab"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_crontab
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/crontab
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/crontab -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/crontab -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/crontab -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/crontab -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/crontab -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/crontab -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_crontab
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - gpasswd [ref]

-a always,exit -F path=/usr/bin/gpasswd -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/gpasswd -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_gpasswd

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/gpasswd"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_gpasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/gpasswd
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/gpasswd -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/gpasswd -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/gpasswd -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/gpasswd -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/gpasswd -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/gpasswd -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_gpasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - newgrp [ref]

-a always,exit -F path=/usr/bin/newgrp -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/newgrp -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_newgrp

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/newgrp"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_newgrp
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/newgrp
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/newgrp -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/newgrp -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/newgrp -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/newgrp -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/newgrp -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/newgrp -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_newgrp
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - pam_timestamp_check [ref]

-a always,exit -F path=/usr/sbin/pam_timestamp_check
-F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/sbin/pam_timestamp_check
-F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_pam_timestamp_check

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/pam_timestamp_check"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_pam_timestamp_check
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/sbin/pam_timestamp_check
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/pam_timestamp_check -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/pam_timestamp_check
        -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/pam_timestamp_check
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/pam_timestamp_check -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/sbin/pam_timestamp_check -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/pam_timestamp_check
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_pam_timestamp_check
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - passwd [ref]

-a always,exit -F path=/usr/bin/passwd -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/passwd -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_passwd

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/passwd"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/passwd
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/passwd -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/passwd -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/passwd -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/passwd -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/passwd -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/passwd -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - postdrop [ref]

-a always,exit -F path=/usr/sbin/postdrop -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/sbin/postdrop -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_postdrop

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/postdrop"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_postdrop
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/sbin/postdrop
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/postdrop -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/postdrop -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/postdrop -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/postdrop -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/sbin/postdrop -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/postdrop -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_postdrop
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - postqueue [ref]

-a always,exit -F path=/usr/sbin/postqueue -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/sbin/postqueue -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_postqueue

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/postqueue"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_postqueue
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/sbin/postqueue
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/postqueue -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/postqueue -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/postqueue -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/postqueue -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/sbin/postqueue -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/postqueue -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_postqueue
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - ssh-keysign [ref]

-a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_ssh_keysign

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/libexec/openssh/ssh-keysign"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_ssh_keysign
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/libexec/openssh/ssh-keysign
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/libexec/openssh/ssh-keysign -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/libexec/openssh/ssh-keysign
        -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/libexec/openssh/ssh-keysign
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/libexec/openssh/ssh-keysign -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/libexec/openssh/ssh-keysign -F auid>=1000 -F auid!=unset
        (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/libexec/openssh/ssh-keysign
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_ssh_keysign
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - su [ref]

-a always,exit -F path=/usr/bin/su -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/su -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_su

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000064-GPOS-0003, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000755-GPOS-00220
app-srg-ctr	SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/su"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_su
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/su
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/su -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/su -F auid>=1000 -F
        auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/su -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/su -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/su -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/su -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_su
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - sudo [ref]

-a always,exit -F path=/usr/bin/sudo -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/sudo -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_sudo

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000755-GPOS-00220
app-srg-ctr	SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255
anssi	R33

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/sudo"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_sudo
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/sudo
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/sudo -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/sudo -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudo -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/sudo -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/sudo -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudo -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_sudo
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - sudoedit [ref]

-a always,exit -F path=/usr/bin/sudoedit -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/sudoedit -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_sudoedit

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000755-GPOS-00220
app-srg-ctr	SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/sudoedit"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_sudoedit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/sudoedit
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/sudoedit -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/sudoedit -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudoedit -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/sudoedit -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/sudoedit -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudoedit -F
        auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_sudoedit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - umount [ref]

-a always,exit -F path=/usr/bin/umount -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/bin/umount -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_umount

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000029-CTR-000085

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/bin/umount"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_umount
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/bin/umount
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/umount -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/umount -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/umount -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/bin/umount -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/bin/umount -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/umount -F auid>=1000
        -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_umount
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - unix_chkpwd [ref]

-a always,exit -F path=/usr/sbin/unix_chkpwd -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/sbin/unix_chkpwd -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_unix_chkpwd

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R6.5
nist	AC-2(4), AU-2(d), AU-3, AU-3.1, AU-12(a), AU-12(c), AU-12.1(ii), AU-12.1(iv), AC-6(9), CM-6(a), MA-4(1)(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/unix_chkpwd"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(a)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-12.1(ii)
  - NIST-800-53-AU-12.1(iv)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-AU-3
  - NIST-800-53-AU-3.1
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(1)(a)
  - audit_rules_privileged_commands_unix_chkpwd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/sbin/unix_chkpwd
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/unix_chkpwd -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/unix_chkpwd -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/unix_chkpwd
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/unix_chkpwd -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/sbin/unix_chkpwd -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/unix_chkpwd
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(a)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-12.1(ii)
  - NIST-800-53-AU-12.1(iv)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-AU-3
  - NIST-800-53-AU-3.1
  - NIST-800-53-CM-6(a)
  - NIST-800-53-MA-4(1)(a)
  - audit_rules_privileged_commands_unix_chkpwd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Ensure auditd Collects Information on the Use of Privileged Commands - userhelper [ref]

-a always,exit -F path=/usr/sbin/userhelper -F auid>=1000 -F auid!=unset -F key=privileged

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add a line of the following form to /etc/audit/audit.rules:

-a always,exit -F path=/usr/sbin/userhelper -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_userhelper

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

ACTION_ARCH_FILTERS="-a always,exit"
OTHER_FILTERS="-F path=/usr/sbin/userhelper"
AUID_FILTERS="-F auid>=1000 -F auid!=unset"
SYSCALL=""
KEY="privileged"
SYSCALL_GROUPING=""
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_userhelper
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for /usr/sbin/userhelper
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/userhelper -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
    set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/userhelper -F auid>=1000
        -F auid!=unset (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/userhelper
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls: []
      syscall_grouping: []

  - name: Check existence of  in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
        path=/usr/sbin/userhelper -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
        -S |,)\w+)+)( -F path=/usr/sbin/userhelper -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/userhelper
        -F auid>=1000 -F auid!=unset -F key=privileged
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - audit_rules_privileged_commands_userhelper
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Group Records Events that Modify Date and Time Information Group contains 5 rules

[ref] Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time. All changes to the system time should be audited.

Rule Record attempts to alter time through adjtimex [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules

The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:

-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_time_adjtimex

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001487, CCI-000169
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.4.2.b
anssi	R73
pcidss4	10.6.3, 10.6

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
    # Create expected audit group and audit rule form for particular system call & architecture
    if [ ${ARCH} = "b32" ]
    then
        ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
        # stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
        # so append it to the list of time group system calls to be audited
        SYSCALL="adjtimex settimeofday stime"
        SYSCALL_GROUPING="adjtimex settimeofday stime"
    elif [ ${ARCH} = "b64" ]
    then
        ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
        # stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
        # therefore don't add it to the list of time group system calls to be audited
        SYSCALL="adjtimex settimeofday"
        SYSCALL_GROUPING="adjtimex settimeofday"
    fi
    OTHER_FILTERS=""
    AUID_FILTERS=""
    KEY="audit_time_rules"
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0600 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()


    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_adjtimex
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set architecture for audit tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_adjtimex
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for adjtimex for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - adjtimex
      syscall_grouping:
      - adjtimex
      - settimeofday
      - stime

  - name: Check existence of adjtimex in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
    set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - adjtimex
      syscall_grouping:
      - adjtimex
      - settimeofday
      - stime

  - name: Check existence of adjtimex in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_adjtimex
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for adjtimex for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - adjtimex
      syscall_grouping:
      - adjtimex
      - settimeofday

  - name: Check existence of adjtimex in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
    set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - adjtimex
      syscall_grouping:
      - adjtimex
      - settimeofday
      - stime

  - name: Check existence of adjtimex in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_adjtimex
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Record Attempts to Alter Time Through clock_settime [ref]

-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change

-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_time_clock_settime

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001487, CCI-000169
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.4.2.b
anssi	R73
pcidss4	10.6.3, 10.6

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS="-F a0=0x0"
	AUID_FILTERS=""
	SYSCALL="clock_settime"
	KEY="time-change"
	SYSCALL_GROUPING=""
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_clock_settime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set architecture for audit tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_clock_settime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for clock_settime for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - clock_settime
      syscall_grouping: []

  - name: Check existence of clock_settime in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
    set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
        key=time-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - clock_settime
      syscall_grouping: []

  - name: Check existence of clock_settime in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
        key=time-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_clock_settime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for clock_settime for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - clock_settime
      syscall_grouping: []

  - name: Check existence of clock_settime in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
    set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
        key=time-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - clock_settime
      syscall_grouping: []

  - name: Check existence of clock_settime in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
        key=time-change
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_clock_settime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Record attempts to alter time through settimeofday [ref]

-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules

If the system is 64 bit then also add the following line:

-a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules

-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_time_settimeofday

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001487, CCI-000169
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.4.2.b
pcidss4	10.6.3, 10.6

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
    # Create expected audit group and audit rule form for particular system call & architecture
    if [ ${ARCH} = "b32" ]
    then
        ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
        # stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
        # so append it to the list of time group system calls to be audited
        SYSCALL="adjtimex settimeofday stime"
        SYSCALL_GROUPING="adjtimex settimeofday stime"
    elif [ ${ARCH} = "b64" ]
    then
        ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
        # stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
        # therefore don't add it to the list of time group system calls to be audited
        SYSCALL="adjtimex settimeofday"
        SYSCALL_GROUPING="adjtimex settimeofday"
    fi
    OTHER_FILTERS=""
    AUID_FILTERS=""
    KEY="audit_time_rules"
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0600 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()


    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_settimeofday
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set architecture for audit tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_settimeofday
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for settimeofday for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - settimeofday
      syscall_grouping:
      - adjtimex
      - settimeofday
      - stime

  - name: Check existence of settimeofday in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
    set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - settimeofday
      syscall_grouping:
      - adjtimex
      - settimeofday
      - stime

  - name: Check existence of settimeofday in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_settimeofday
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for settimeofday for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - settimeofday
      syscall_grouping:
      - adjtimex
      - settimeofday
      - stime

  - name: Check existence of settimeofday in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
    set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - settimeofday
      syscall_grouping:
      - adjtimex
      - settimeofday
      - stime

  - name: Check existence of settimeofday in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_settimeofday
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Record Attempts to Alter Time Through stime [ref]

-a always,exit -F arch=b32 -S stime -F key=audit_time_rules

Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file for both 32 bit and 64 bit systems:

-a always,exit -F arch=b32 -S stime -F key=audit_time_rules

Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined system calls:

-a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_time_stime

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001487, CCI-000169
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.4.2.b
anssi	R73
pcidss4	10.6.3, 10.6

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel && { ( ! ( grep -q aarch64 /proc/sys/kernel/osrelease ) && ! ( grep -q s390x /proc/sys/kernel/osrelease ) ); }; then

# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
    # Create expected audit group and audit rule form for particular system call & architecture
    if [ ${ARCH} = "b32" ]
    then
        ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
        # stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
        # so append it to the list of time group system calls to be audited
        SYSCALL="adjtimex settimeofday stime"
        SYSCALL_GROUPING="adjtimex settimeofday stime"
    elif [ ${ARCH} = "b64" ]
    then
        ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
        # stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
        # therefore don't add it to the list of time group system calls to be audited
        SYSCALL="adjtimex settimeofday"
        SYSCALL_GROUPING="adjtimex settimeofday"
    fi
    OTHER_FILTERS=""
    AUID_FILTERS=""
    KEY="audit_time_rules"
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0600 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()


    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_stime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Perform remediation of Audit rules for stime syscall for x86 platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - stime
      syscall_grouping:
      - adjtimex
      - settimeofday
      - stime

  - name: Check existence of stime in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
    set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - stime
      syscall_grouping:
      - adjtimex
      - settimeofday
      - stime

  - name: Check existence of stime in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ( not ( ansible_architecture == "aarch64" ) and not ( ansible_architecture ==
    "s390x" ) )
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_stime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Record Attempts to Alter the localtime File [ref]

-w /etc/localtime -p wa -k audit_time_rules

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-w /etc/localtime -p wa -k audit_time_rules

The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport and should always be used.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_time_watch_localtime

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001487, CCI-000169
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.4.2.b
anssi	R73
pcidss4	10.6.3, 10.6

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_time_rules.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/localtime" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_time_rules.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_time_rules.rules"
    # If the audit_time_rules.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_watch_localtime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/localtime already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_watch_localtime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_time_rules
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_watch_localtime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_time_rules.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_watch_localtime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_watch_localtime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/localtime in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/localtime -p wa -k audit_time_rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_watch_localtime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/localtime already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_watch_localtime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/localtime in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/localtime -p wa -k audit_time_rules
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.4.2.b
  - PCI-DSSv4-10.6
  - PCI-DSSv4-10.6.3
  - audit_rules_time_watch_localtime
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Make the auditd Configuration Immutable [ref]

-e 2

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file in order to make the auditd configuration immutable:

-e 2

With this setting, a reboot will be required to change any audit rules.

Rationale:

Making the audit configuration immutable prevents accidental as well as malicious modification of the audit rules, although it may be problematic if legitimate changes are needed during system operation.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_immutable

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO01.06, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.3.1, 3.4.3
disa	CCI-000163, CCI-000164, CCI-000162
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.310(a)(2)(iv), 164.312(d), 164.310(d)(2)(iii), 164.312(b), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nist	AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.5.2
os-srg	SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029
app-srg-ctr	SRG-APP-000119-CTR-000245, SRG-APP-000120-CTR-000250
anssi	R73
pcidss4	10.3.2, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Traverse all of:
#
# /etc/audit/audit.rules,			(for auditctl case)
# /etc/audit/rules.d/*.rules			(for augenrules case)
#
# files to check if '-e .*' setting is present in that '*.rules' file already.
# If found, delete such occurrence since auditctl(8) manual page instructs the
# '-e 2' rule should be placed as the last rule in the configuration
find /etc/audit /etc/audit/rules.d -maxdepth 1 -type f -name '*.rules' -exec sed -i '/-e[[:space:]]\+.*/d' {} ';'

# Append '-e 2' requirement at the end of both:
# * /etc/audit/audit.rules file 		(for auditctl case)
# * /etc/audit/rules.d/immutable.rules		(for augenrules case)

for AUDIT_FILE in "/etc/audit/audit.rules" "/etc/audit/rules.d/immutable.rules"
do
	echo '' >> $AUDIT_FILE
	echo '# Set the audit.rules configuration immutable per security requirements' >> $AUDIT_FILE
	echo '# Reboot is required to change audit rules once this setting is applied' >> $AUDIT_FILE
	echo '-e 2' >> $AUDIT_FILE
	chmod o-rwx $AUDIT_FILE
	chmod g-rwx $AUDIT_FILE
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-171-3.4.3
  - NIST-800-53-AC-6(9)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.2
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.2
  - audit_rules_immutable
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Collect all files from /etc/audit/rules.d with .rules extension
  find:
    paths: /etc/audit/rules.d/
    patterns: '*.rules'
  register: find_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-171-3.4.3
  - NIST-800-53-AC-6(9)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.2
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.2
  - audit_rules_immutable
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Remove the -e option from all Audit config files
  lineinfile:
    path: '{{ item }}'
    regexp: ^\s*(?:-e)\s+.*$
    state: absent
  loop: '{{ find_rules_d.files | map(attribute=''path'') | list + [''/etc/audit/audit.rules'']
    }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-171-3.4.3
  - NIST-800-53-AC-6(9)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.2
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.2
  - audit_rules_immutable
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add Audit -e option into /etc/audit/rules.d/immutable.rules and /etc/audit/audit.rules
  lineinfile:
    path: '{{ item }}'
    create: true
    line: -e 2
    mode: g-rwx,o-rwx
  loop:
  - /etc/audit/audit.rules
  - /etc/audit/rules.d/immutable.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-171-3.4.3
  - NIST-800-53-AC-6(9)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.2
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.2
  - audit_rules_immutable
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Mandatory Access Controls [ref]

-w /etc/selinux/ -p wa -k MAC-policy

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-w /etc/selinux/ -p wa -k MAC-policy

Rationale:

The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_mac_modification

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.8
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/selinux/" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/selinux/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/selinux/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/selinux/ -p wa -k MAC-policy" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/MAC-policy.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/selinux/" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/MAC-policy.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/MAC-policy.rules"
    # If the MAC-policy.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/selinux/" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/selinux/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/selinux/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/selinux/ -p wa -k MAC-policy" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.8
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_mac_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.8
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_mac_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key MAC-policy
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)MAC-policy$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.8
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_mac_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/MAC-policy.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/MAC-policy.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.8
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_mac_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.8
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_mac_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/selinux/ in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/selinux/ -p wa -k MAC-policy
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.8
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_mac_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.8
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_mac_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/selinux/ in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/selinux/ -p wa -k MAC-policy
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.8
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_mac_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Ensure auditd Collects Information on Exporting to Media (successful) [ref]

At a minimum, the audit system should collect media exportation events for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export

-a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export

Rationale:

The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_media_export

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.7
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215
app-srg-ctr	SRG-APP-000495-CTR-001235
anssi	R73
pcidss4	10.2.1.7, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
	SYSCALL="mount"
	KEY="perm_mod"
	SYSCALL_GROUPING=""

	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_media_export
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Set architecture for audit mount tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_media_export
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for mount for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - mount
      syscall_grouping: []

  - name: Check existence of mount in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - mount
      syscall_grouping: []

  - name: Check existence of mount in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_media_export
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Perform remediation of Audit rules for mount for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - mount
      syscall_grouping: []

  - name: Check existence of mount in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
    set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
        |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - mount
      syscall_grouping: []

  - name: Check existence of mount in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
        key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
        -F auid!=unset -F key=perm_mod
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.7
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.7
  - audit_rules_media_export
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify the System's Network Environment [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification

-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, setting ARCH to either b32 or b64 as appropriate for your system:

-a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
-w /etc/issue -p wa -k audit_rules_networkconfig_modification
-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
-w /etc/hosts -p wa -k audit_rules_networkconfig_modification
-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification

Rationale:

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_networkconfig_modification

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.5.5
anssi	R73
pcidss4	10.3.4, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# First perform the remediation of the syscall rule
# Retrieve hardware architecture of the underlying system
[ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

for ARCH in "${RULE_ARCHS[@]}"
do
	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
	OTHER_FILTERS=""
	AUID_FILTERS=""
	SYSCALL="sethostname setdomainname"
	KEY="audit_rules_networkconfig_modification"
	SYSCALL_GROUPING="sethostname setdomainname"
	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()

# If audit tool is 'augenrules', then check if the audit rule is defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
# If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
default_file="/etc/audit/rules.d/$KEY.rules"
# As other_filters may include paths, lets use a different delimiter for it
# The "F" script expression tells sed to print the filenames where the expressions matched
readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
# Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
if [ ${#files_to_inspect[@]} -eq "0" ]
then
    file_to_inspect="/etc/audit/rules.d/$KEY.rules"
    files_to_inspect=("$file_to_inspect")
    if [ ! -e "$file_to_inspect" ]
    then
        touch "$file_to_inspect"
        chmod 0600 "$file_to_inspect"
    fi
fi

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
	unset syscall_a
unset syscall_grouping
unset syscall_string
unset syscall
unset file_to_edit
unset rule_to_edit
unset rule_syscalls_to_edit
unset other_string
unset auid_string
unset full_rule

# Load macro arguments into arrays
read -a syscall_a <<< $SYSCALL
read -a syscall_grouping <<< $SYSCALL_GROUPING

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
#  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
# -----------------------------------------------------------------------------------------
#        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
# -----------------------------------------------------------------------------------------
#        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
#        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
#
files_to_inspect=()


# If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# file to the list of files to be inspected
default_file="/etc/audit/audit.rules"
files_to_inspect+=('/etc/audit/audit.rules' )

# After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
skip=1

for audit_file in "${files_to_inspect[@]}"
do
    # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
    # i.e, collect rules that match:
    # * the action, list and arch, (2-nd argument)
    # * the other filters, (3-rd argument)
    # * the auid filters, (4-rd argument)
    readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

    candidate_rules=()
    # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
    for s_rule in "${similar_rules[@]}"
    do
        # Strip all the options and fields we know of,
        # than check if there was any field left over
        extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
        grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
    done

    if [[ ${#syscall_a[@]} -ge 1 ]]
    then
        # Check if the syscall we want is present in any of the similar existing rules
        for rule in "${candidate_rules[@]}"
        do
            rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
            all_syscalls_found=0
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                   # A syscall was not found in the candidate rule
                   all_syscalls_found=1
                   }
            done
            if [[ $all_syscalls_found -eq 0 ]]
            then
                # We found a rule with all the syscall(s) we want; skip rest of macro
                skip=0
                break
            fi

            # Check if this rule can be grouped with our target syscall and keep track of it
            for syscall_g in "${syscall_grouping[@]}"
            do
                if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                then
                    file_to_edit=${audit_file}
                    rule_to_edit=${rule}
                    rule_syscalls_to_edit=${rule_syscalls}
                fi
            done
        done
    else
        # If there is any candidate rule, it is compliant; skip rest of macro
        if [ "${#candidate_rules[@]}" -gt 0 ]
        then
            skip=0
        fi
    fi

    if [ "$skip" -eq 0 ]; then
        break
    fi
done

if [ "$skip" -ne 0 ]; then
    # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
    # At this point we know if we need to either append the $full_rule or group
    # the syscall together with an exsiting rule

    # Append the full_rule if it cannot be grouped to any other rule
    if [ -z ${rule_to_edit+x} ]
    then
        # Build full_rule while avoid adding double spaces when other_filters is empty
        if [ "${#syscall_a[@]}" -gt 0 ]
        then
            syscall_string=""
            for syscall in "${syscall_a[@]}"
            do
                syscall_string+=" -S $syscall"
            done
        fi
        other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
        auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
        full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
        echo "$full_rule" >> "$default_file"
        chmod o-rwx ${default_file}
    else
        # Check if the syscalls are declared as a comma separated list or
        # as multiple -S parameters
        if grep -q -- "," <<< "${rule_syscalls_to_edit}"
        then
            delimiter=","
        else
            delimiter=" -S "
        fi
        new_grouped_syscalls="${rule_syscalls_to_edit}"
        for syscall in "${syscall_a[@]}"
        do
            grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
               # A syscall was not found in the candidate rule
               new_grouped_syscalls+="${delimiter}${syscall}"
               }
        done

        # Group the syscall in the rule
        sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
    fi
fi
done

# Then perform the remediations for the watch rules
# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
    # If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue.net" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
    # If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/hosts" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
    # If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
    fi
done

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sysconfig/network" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
    # If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set architecture for audit tasks
  set_fact:
    audit_arch: b64
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
    == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Remediate audit rules for network configuration for 32bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - sethostname
      - setdomainname
      syscall_grouping:
      - sethostname
      - setdomainname

  - name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
    set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - sethostname
      - setdomainname
      syscall_grouping:
      - sethostname
      - setdomainname

  - name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Remediate audit rules for network configuration for 64bit platform
  block:

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - sethostname
      - setdomainname
      syscall_grouping:
      - sethostname
      - setdomainname

  - name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
    find:
      paths: /etc/audit/rules.d
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: '*.rules'
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Reset syscalls found per file
    set_fact:
      syscalls_per_file: {}
      found_paths_dict: {}

  - name: Declare syscalls found per file
    set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
      :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
    loop: '{{ find_command.results | selectattr(''matched'') | list }}'

  - name: Declare files where syscalls were found
    set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
      | map(attribute='path') | list }}"

  - name: Count occurrences of syscalls in paths
    set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
      0) }) }}"
    loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
      | list }}'

  - name: Get path with most syscalls
    set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
      | last).key }}"
    when: found_paths | length >= 1

  - name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
    set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
    when: found_paths | length == 0

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
        | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0

  - name: Declare list of syscalls
    set_fact:
      syscalls:
      - sethostname
      - setdomainname
      syscall_grouping:
      - sethostname
      - setdomainname

  - name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
    find:
      paths: /etc/audit
      contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
        |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
      patterns: audit.rules
    register: find_command
    loop: '{{ (syscall_grouping + syscalls) | unique }}'

  - name: Set path to /etc/audit/audit.rules
    set_fact: audit_file="/etc/audit/audit.rules"

  - name: Declare found syscalls
    set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
      | list }}"

  - name: Declare missing syscalls
    set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

  - name: Replace the audit rule in {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
        join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
      line: \1\2\3{{ missing_syscalls | join("\3") }}\4
      backrefs: true
      state: present
    when: syscalls_found | length > 0 and missing_syscalls | length > 0

  - name: Add the audit rule to {{ audit_file }}
    lineinfile:
      path: '{{ audit_file }}'
      line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
      create: true
      mode: g-rwx,o-rwx
      state: present
    when: syscalls_found | length == 0
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - audit_arch == "b64"
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/issue already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
    recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/issue in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/issue already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/issue in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
    recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/issue.net in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/issue.net already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/issue.net in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/hosts already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
    recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/hosts in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/hosts already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/hosts in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
    recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/sysconfig/network in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/sysconfig/network in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.4
  - audit_rules_networkconfig_modification
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Record Attempts to Alter Process and Session Initiation Information [ref]

The audit system already collects process information for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d in order to watch for attempted manual edits of files involved in storing such process information:

-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file in order to watch for attempted manual edits of files involved in storing such process information:

-w /var/run/utmp -p wa -k session
-w /var/log/btmp -p wa -k session
-w /var/log/wtmp -p wa -k session

Rationale:

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_session_events

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
ism	0582, 0584, 05885, 0586, 0846, 0957
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AU-2(d), AU-12(c), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.3
app-srg-ctr	SRG-APP-000505-CTR-001285
anssi	R73
pcidss4	10.2.1.3, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/run/utmp" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/session.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/session.rules"
    # If the session.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/btmp" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/session.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/session.rules"
    # If the session.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/wtmp" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/session.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/session.rules"
    # If the session.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key session
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)session$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/session.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/run/utmp in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /var/run/utmp -p wa -k session
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/run/utmp already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/run/utmp in /etc/audit/audit.rules
  lineinfile:
    line: -w /var/run/utmp -p wa -k session
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key session
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)session$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/session.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/log/btmp in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /var/log/btmp -p wa -k session
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/log/btmp already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/log/btmp in /etc/audit/audit.rules
  lineinfile:
    line: -w /var/log/btmp -p wa -k session
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key session
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)session$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/session.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/log/wtmp in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /var/log/wtmp -p wa -k session
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /var/log/wtmp in /etc/audit/audit.rules
  lineinfile:
    line: -w /var/log/wtmp -p wa -k session
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.3
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.3
  - audit_rules_session_events
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Ensure auditd Collects System Administrator Actions [ref]

At a minimum, the audit system should collect administrator actions for all users and root. If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to a file with suffix .rules in the directory /etc/audit/rules.d:

-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to /etc/audit/audit.rules file:

-w /etc/sudoers -p wa -k actions
-w /etc/sudoers.d/ -p wa -k actions

Rationale:

The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_sysadmin_actions

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nist	AC-2(7)(b), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.2, Req-10.2.5.b
os-srg	SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221
app-srg-ctr	SRG-APP-000026-CTR-000070, SRG-APP-000027-CTR-000075, SRG-APP-000028-CTR-000080, SRG-APP-000291-CTR-000675, SRG-APP-000292-CTR-000680, SRG-APP-000293-CTR-000685, SRG-APP-000294-CTR-000690, SRG-APP-000319-CTR-000745, SRG-APP-000320-CTR-000750, SRG-APP-000509-CTR-001305
anssi	R73
pcidss4	10.2.1.5, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/actions.rules"
    # If the actions.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers.d/" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/actions.rules"
    # If the actions.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/sudoers already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/sudoers\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/sudoers in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/sudoers -p wa -k actions
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/sudoers already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/sudoers\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key actions
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)actions$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/actions.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/sudoers in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/sudoers -p wa -k actions
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/sudoers.d/ already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/sudoers.d/\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/sudoers.d/ in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/sudoers.d/ -p wa -k actions
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Check if watch rule for /etc/sudoers.d/ already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/sudoers.d/\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key actions
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)actions$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/actions.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Add watch rule for /etc/sudoers.d/ in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/sudoers.d/ -p wa -k actions
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(7)(b)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.2
  - PCI-DSS-Req-10.2.5.b
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_sysadmin_actions
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Shutdown System When Auditing Failures Occur [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following line to to the bottom of a file with suffix .rules in the directory /etc/audit/rules.d:

-f 2

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following line to the bottom of the /etc/audit/audit.rules file:

-f 2

Rationale:

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected.

Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_system_shutdown

References:

cis-csc	1, 14, 15, 16, 3, 5, 6
cobit5	APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01
cui	3.3.1, 3.3.4
disa	CCI-000140, CCI-000139
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1
nist	AU-5(b), SC-24, CM-6(a)
nist-csf	PR.PT-1
os-srg	SRG-OS-000046-GPOS-00022, SRG-OS-000047-GPOS-00023

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_audit_failure_mode='2'


# Traverse all of:
#
# /etc/audit/audit.rules,			(for auditctl case)
# /etc/audit/rules.d/*.rules			(for augenrules case)
find /etc/audit /etc/audit/rules.d -maxdepth 1 -type f -name '*.rules' -exec sed -i '/-f[[:space:]]\+.*/d' {} ';'

for AUDIT_FILE in "/etc/audit/audit.rules" "/etc/audit/rules.d/immutable.rules"
do
	echo '' >> $AUDIT_FILE
	echo '# Set the audit.rules configuration to halt system upon audit failure per security requirements' >> $AUDIT_FILE
	echo "-f $var_audit_failure_mode" >> $AUDIT_FILE
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.3.1
  - NIST-800-171-3.3.4
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-24
  - audit_rules_system_shutdown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy
- name: XCCDF Value var_audit_failure_mode # promote to variable
  set_fact:
    var_audit_failure_mode: !!str 2
  tags:
    - always

- name: Collect all files from /etc/audit/rules.d with .rules extension
  find:
    paths: /etc/audit/rules.d/
    patterns: '*.rules'
  register: find_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.3.1
  - NIST-800-171-3.3.4
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-24
  - audit_rules_system_shutdown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Remove the -f option from all Audit config files
  lineinfile:
    path: '{{ item }}'
    regexp: ^\s*(?:-f)\s+.*$
    state: absent
  loop: '{{ find_rules_d.files | map(attribute=''path'') | list + [''/etc/audit/audit.rules'']
    }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.3.1
  - NIST-800-171-3.3.4
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-24
  - audit_rules_system_shutdown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add Audit -f option into /etc/audit/rules.d/immutable.rules and /etc/audit/audit.rules
  lineinfile:
    path: '{{ item }}'
    create: true
    mode: '0600'
    line: -f {{ var_audit_failure_mode }}
  loop:
  - /etc/audit/audit.rules
  - /etc/audit/rules.d/immutable.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.3.1
  - NIST-800-171-3.3.4
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SC-24
  - audit_rules_system_shutdown
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify User/Group Information - /etc/group [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/group -p wa -k audit_rules_usergroup_modification

If the auditd daemon is configured to use the auditctl utility to read audit rules during daemon startup, add the following lines to /etc/audit/audit.rules file, in order to capture events that modify account changes:

-w /etc/group -p wa -k audit_rules_usergroup_modification

Rationale:

In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_group

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001403, CCI-001404, CCI-001405, CCI-000172, CCI-000130, CCI-002130, CCI-000135, CCI-000169, CCI-002884, CCI-000018, CCI-000015
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.5
os-srg	SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275
anssi	R73
pcidss4	10.2.1.5, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/group" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/group" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
    # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/group" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_group
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/group already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/group\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_group
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_group
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
    for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_group
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_group
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/group in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/group -p wa -k audit_rules_usergroup_modification
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_group
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/group already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/group\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_group
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/group in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/group -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_group
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify User/Group Information - /etc/gshadow [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/gshadow -p wa -k audit_rules_usergroup_modification

-w /etc/gshadow -p wa -k audit_rules_usergroup_modification

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_gshadow

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001403, CCI-001404, CCI-001405, CCI-000172, CCI-000130, CCI-002130, CCI-000135, CCI-000169, CCI-002884, CCI-000018, CCI-000015
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.5
os-srg	SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275
anssi	R73
pcidss4	10.2.1.5, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/gshadow" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
    # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_gshadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/gshadow already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/gshadow\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_gshadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_gshadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
    for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_gshadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_gshadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/gshadow in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_gshadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/gshadow already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/gshadow\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_gshadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/gshadow in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_gshadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify User/Group Information - /etc/security/opasswd [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_opasswd

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001403, CCI-001404, CCI-001405, CCI-000172, CCI-000130, CCI-002130, CCI-000135, CCI-000169, CCI-002884, CCI-000018, CCI-000015
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.5
os-srg	SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000503-CTR-001275
anssi	R73
pcidss4	10.2.1.5, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/security/opasswd" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
    # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_opasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/security/opasswd already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/security/opasswd\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_opasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_opasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
    for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_opasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_opasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/security/opasswd in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_opasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/security/opasswd already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/security/opasswd\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_opasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/security/opasswd in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_opasswd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify User/Group Information - /etc/passwd [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/passwd -p wa -k audit_rules_usergroup_modification

-w /etc/passwd -p wa -k audit_rules_usergroup_modification

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_passwd

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001403, CCI-001404, CCI-001405, CCI-000172, CCI-000130, CCI-002130, CCI-000135, CCI-000169, CCI-002884, CCI-000018, CCI-000015
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.5
os-srg	SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000274-GPOS-00104, SRG-OS-000275-GPOS-00105, SRG-OS-000276-GPOS-00106, SRG-OS-000277-GPOS-00107
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275
anssi	R73
pcidss4	10.2.1.5, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/passwd" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
    # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/passwd already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/passwd\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
    for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/passwd in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/passwd already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/passwd\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/passwd in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_passwd
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule Record Events that Modify User/Group Information - /etc/shadow [ref]

If the auditd daemon is configured to use the augenrules program to read audit rules during daemon startup (the default), add the following lines to a file with suffix .rules in the directory /etc/audit/rules.d, in order to capture events that modify account changes:

-w /etc/shadow -p wa -k audit_rules_usergroup_modification

-w /etc/shadow -p wa -k audit_rules_usergroup_modification

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_shadow

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.1.7
disa	CCI-001403, CCI-001404, CCI-001405, CCI-000172, CCI-000130, CCI-002130, CCI-000135, CCI-000169, CCI-002884, CCI-000018, CCI-000015
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5
nerc-cip	CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3
nist	AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
pcidss	Req-10.2.5
os-srg	SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221
app-srg-ctr	SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275
anssi	R73
pcidss4	10.2.1.5, 10.2.1, 10.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()


# If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
# into the list of files to be inspected
files_to_inspect+=('/etc/audit/audit.rules')

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done
# Create a list of audit *.rules files that should be inspected for presence and correctness
# of a particular audit rule. The scheme is as follows:
#
# -----------------------------------------------------------------------------------------
# Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
# -----------------------------------------------------------------------------------------
#	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
# -----------------------------------------------------------------------------------------
# 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
# 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
# -----------------------------------------------------------------------------------------
files_to_inspect=()

# If the audit is 'augenrules', then check if rule is already defined
# If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
# If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/shadow" /etc/audit/rules.d/*.rules)

# For each of the matched entries
for match in "${matches[@]}"
do
    # Extract filepath from the match
    rulesd_audit_file=$(echo $match | cut -f1 -d ':')
    # Append that path into list of files for inspection
    files_to_inspect+=("$rulesd_audit_file")
done
# Case when particular audit rule isn't defined yet
if [ "${#files_to_inspect[@]}" -eq "0" ]
then
    # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
    key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
    # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
    if [ ! -e "$key_rule_file" ]
    then
        touch "$key_rule_file"
        chmod 0600 "$key_rule_file"
    fi
    files_to_inspect+=("$key_rule_file")
fi

# Finally perform the inspection and possible subsequent audit rule
# correction for each of the files previously identified for inspection
for audit_rules_file in "${files_to_inspect[@]}"
do
    # Check if audit watch file system object rule for given path already present
    if grep -q -P -- "^[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
    then
        # Rule is found => verify yet if existing rule definition contains
        # all of the required access type bits

        # Define BRE whitespace class shortcut
        sp="[[:space:]]"
        # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
        current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
        # Split required access bits string into characters array
        # (to check bit's presence for one bit at a time)
        for access_bit in $(echo "wa" | grep -o .)
        do
            # For each from the required access bits (e.g. 'w', 'a') check
            # if they are already present in current access bits for rule.
            # If not, append that bit at the end
            if ! grep -q "$access_bit" <<< "$current_access_bits"
            then
                # Concatenate the existing mask with the missing bit
                current_access_bits="$current_access_bits$access_bit"
            fi
        done
        # Propagate the updated rule's access bits (original + the required
        # ones) back into the /etc/audit/audit.rules file for that rule
        sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
    else
        # Rule isn't present yet. Append it at the end of $audit_rules_file file
        # with proper key

        echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
    fi
done

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_shadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/shadow already exists in /etc/audit/rules.d/
  find:
    paths: /etc/audit/rules.d
    contains: ^\s*-w\s+/etc/shadow\s+-p\s+wa(\s|$)+
    patterns: '*.rules'
  register: find_existing_watch_rules_d
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_shadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
  find:
    paths: /etc/audit/rules.d
    contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
    patterns: '*.rules'
  register: find_watch_key
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_shadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
    for the rule
  set_fact:
    all_files:
    - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_shadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Use matched file as the recipient for the rule
  set_fact:
    all_files:
    - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
    is defined and find_existing_watch_rules_d.matched == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_shadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/shadow in /etc/audit/rules.d/
  lineinfile:
    path: '{{ all_files[0] }}'
    line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_shadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Check if watch rule for /etc/shadow already exists in /etc/audit/audit.rules
  find:
    paths: /etc/audit/
    contains: ^\s*-w\s+/etc/shadow\s+-p\s+wa(\s|$)+
    patterns: audit.rules
  register: find_existing_watch_audit_rules
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_shadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

- name: Add watch rule for /etc/shadow in /etc/audit/audit.rules
  lineinfile:
    line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    state: present
    dest: /etc/audit/audit.rules
    create: true
    mode: '0600'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
    == 0
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.1.7
  - NIST-800-53-AC-2(4)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - PCI-DSSv4-10.2.1.5
  - audit_rules_usergroup_modification_shadow
  - low_complexity
  - low_disruption
  - medium_severity
  - reboot_required
  - restrict_strategy

Rule System Audit Logs Must Be Owned By Root [ref]

All audit logs must be owned by root user and group. By default, the path for audit log is

/var/log/audit/

. To properly set the owner of /var/log/audit, run the command:

$ sudo chown root /var/log/audit

To properly set the owner of /var/log/audit/*, run the command:

$ sudo chown root /var/log/audit/*

Rationale:

Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_ownership_var_log_audit

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO01.06, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA02.01
cui	3.3.1
disa	CCI-000162, CCI-000163, CCI-000164, CCI-001314
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-6(a), AC-6(1), AU-9(4)
nist-csf	DE.AE-3, DE.AE-5, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.5.1
os-srg	SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029
app-srg-ctr	SRG-APP-000118-CTR-000240
pcidss4	10.3.2, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

if LC_ALL=C grep -m 1 -q ^log_group /etc/audit/auditd.conf; then
  GROUP=$(awk -F "=" '/log_group/ {print $2}' /etc/audit/auditd.conf | tr -d ' ')
  if ! [ "${GROUP}" == 'root' ] ; then
    chown root:${GROUP} /var/log/audit
    chown root:${GROUP} /var/log/audit/audit.log*
  else
    chown root:root /var/log/audit
    chown root:root /var/log/audit/audit.log*
  fi
else
  chown root:root /var/log/audit
  chown root:root /var/log/audit/audit.log*
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Rule System Audit Logs Must Have Mode 0640 or Less Permissive [ref]

If log_group in /etc/audit/auditd.conf is set to a group other than the root group account, change the mode of the audit log files with the following command:

$ sudo chmod 0640 audit_file

Otherwise, change the mode of the audit log files with the following command:

$ sudo chmod 0600 audit_file

Rationale:

If users can write to audit logs, audit trails can be modified or destroyed.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permissions_var_log_audit

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO01.06, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA02.01
cui	3.3.1
disa	CCI-000163, CCI-000164, CCI-001314, CCI-000162
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1
iso27001-2013	A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5
nerc-cip	CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2
nist	CM-6(a), AC-6(1), AU-9(4)
nist-csf	DE.AE-3, DE.AE-5, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.5
os-srg	SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000206-GPOS-00084
app-srg-ctr	SRG-APP-000118-CTR-000240
pcidss4	10.3.1, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

if LC_ALL=C grep -iw ^log_file /etc/audit/auditd.conf; then
    FILE=$(awk -F "=" '/^log_file/ {print $2}' /etc/audit/auditd.conf | tr -d ' ')
else
    FILE="/var/log/audit/audit.log"
fi


if LC_ALL=C grep -m 1 -q ^log_group /etc/audit/auditd.conf; then
  GROUP=$(awk -F "=" '/log_group/ {print $2}' /etc/audit/auditd.conf | tr -d ' ')
  if ! [ "${GROUP}" == 'root' ] ; then
    chmod 0640 $FILE
    chmod 0440 $FILE.*
  else
    chmod 0600 $FILE
    chmod 0400 $FILE.*
  fi
else
  chmod 0600 $FILE
  chmod 0400 $FILE.*
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Get audit log files
  command: grep -iw ^log_file /etc/audit/auditd.conf
  failed_when: false
  register: log_file_exists
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Parse log file line
  command: awk -F '=' '/^log_file/ {print $2}' /etc/audit/auditd.conf
  register: log_file_line
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - log_file_exists is not skipped and (log_file_exists.stdout | length > 0)
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set default log_file if not set
  set_fact:
    log_file: /var/log/audit/audit.log
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - (log_file_exists is skipped) or (log_file_exists is undefined) or (log_file_exists.stdout
    | length == 0)
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set log_file from log_file_line if not set already
  set_fact:
    log_file: '{{ log_file_line.stdout | trim }}'
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - (log_file_exists is not skipped) and (log_file_line.stdout is defined) and (log_file_line.stdout
    | length > 0)
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Get log files group
  command: grep -m 1 ^log_group /etc/audit/auditd.conf
  failed_when: false
  register: log_group_line
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Parse log group line
  command: awk -F '=' '/log_group/ {print $2}' /etc/audit/auditd.conf
  register: log_group
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - (log_group_line is not skipped) and (log_group_line.stdout | length > 0)
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Apply mode to log file when group root
  file:
    path: '{{ log_file }}'
    mode: (( log_group is defined ) and ( ( log_group.stdout | trim ) == 'root' ))
      | ternary( '0600', '0640')
  failed_when: false
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - log_group is not skipped
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: List all log file backups
  find:
    path: '{{ log_file | dirname }}'
    patterns: '{{ log_file | basename }}.*'
  register: backup_files
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Apply mode to log file when group not root
  file:
    path: '{{ item }}'
    mode: (( log_group is defined ) and ( ( log_group.stdout | trim ) == 'root' ))  |
      ternary( '0400', '0440')
  loop: '{{ backup_files.files| map(attribute=''path'') | list }}'
  failed_when: false
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  - backup_files is not skipped
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-6(1)
  - NIST-800-53-AU-9(4)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.1
  - file_permissions_var_log_audit
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Group Configure auditd Data Retention Group contains 13 rules

[ref] The audit system writes data to /var/log/audit/audit.log. By default, auditd rotates 5 logs by size (6MB), retaining a maximum of 30MB of data in total, and refuses to write entries when the disk is too full. This minimizes the risk of audit data filling its partition and impacting other services. This also minimizes the risk of the audit daemon temporarily disabling the system if it cannot write audit log (which it can be configured to do). For a busy system or a system which is thoroughly auditing system activity, the default settings for data retention may be insufficient. The log file size needed will depend heavily on what types of events are being audited. First configure auditing to log all the events of interest. Then monitor the log size manually for awhile to determine what file size will allow you to keep the required data for the correct time period.

Using a dedicated partition for /var/log/audit prevents the auditd logs from disrupting system functionality if they fill, and, more importantly, prevents other activity in /var from filling the partition and stopping the audit trail. (The audit logs are size-limited and therefore unlikely to grow without bound unless configured to do so.) Some machines may have requirements that no actions occur which cannot be audited. If this is the case, then auditd can be configured to halt the machine if it runs out of space. Note: Since older logs are rotated, configuring auditd this way does not prevent older logs from being rotated away before they can be viewed. If your system is configured to halt when logging cannot be performed, make sure this can never happen under normal circumstances! Ensure that /var/log/audit is on its own partition, and that this partition is larger than the maximum amount of data auditd will retain normally.

Rule Configure audispd Plugin To Send Logs To Remote Server [ref]

Configure the audispd plugin to off-load audit records onto a different system or media from the system being audited. Set the remote_server option in

/etc/audit/audisp-remote.conf

with an IP address or hostname of the system that the audispd plugin should send audit records to. For example

remote_server = logcollector

Rationale:

Information stored in one location is vulnerable to accidental or incidental deletion or alteration.Off-loading is a common process in information systems with limited audit storage capacity.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_audispd_configure_remote_server

References:

disa	CCI-001851
os-srg	SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_audispd_remote_server='logcollector'


AUDITCONFIG=/etc/audit/audisp-remote.conf



if [ -e "$AUDITCONFIG" ] ; then
    
    LC_ALL=C sed -i "/^\s*remote_server\s*=\s*/Id" "$AUDITCONFIG"
else
    printf '%s\n' "Path '$AUDITCONFIG' wasn't found on this system. Refusing to continue." >&2
    return 1
fi
# make sure file has newline at the end
sed -i -e '$a\' "$AUDITCONFIG"

cp "$AUDITCONFIG" "$AUDITCONFIG.bak"
# Insert at the end of the file
printf '%s\n' "remote_server = $var_audispd_remote_server" >> "$AUDITCONFIG"
# Clean up after ourselves.
rm "$AUDITCONFIG.bak"

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - auditd_audispd_configure_remote_server
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value var_audispd_remote_server # promote to variable
  set_fact:
    var_audispd_remote_server: !!str logcollector
  tags:
    - always

- name: Configure audispd Plugin To Send Logs To Remote Server - Make sure that a
    remote server is configured for Audispd
  ansible.builtin.lineinfile:
    path: /etc/audit/audisp-remote.conf
    line: remote_server = {{ var_audispd_remote_server }}
    regexp: ^\s*remote_server\s*=.*$
    create: true
    state: present
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - auditd_audispd_configure_remote_server
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Configure audispd's Plugin disk_full_action When Disk Is Full [ref]

Configure the action the operating system takes if the disk the audit records are written to becomes full. Edit the file /etc/audit/audisp-remote.conf. Add or modify the following line, substituting ACTION appropriately:

disk_full_action = ACTION

Set this value to single to cause the system to switch to single user mode for corrective action. Acceptable values also include syslog and halt. For certain systems, the need for availability outweighs the need to log all actions, and a different setting should be determined.

Rationale:

Taking appropriate action in case of a filled audit storage volume will minimize the possibility of losing audit records.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_audispd_disk_full_action

References:

disa	CCI-001851
nist	AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a)
os-srg	SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_audispd_disk_full_action='single'


AUDITCONFIG=/etc/audit/audisp-remote.conf

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^disk_full_action")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_audispd_disk_full_action"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^disk_full_action\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^disk_full_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
    if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - auditd_audispd_disk_full_action
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value var_audispd_disk_full_action # promote to variable
  set_fact:
    var_audispd_disk_full_action: !!str single
  tags:
    - always

- name: Make sure that disk full action is configured for Audispd
  lineinfile:
    path: /etc/audit/audisp-remote.conf
    line: disk_full_action = {{ var_audispd_disk_full_action }}
    regexp: ^\s*disk_full_action\s*=.*$
    create: true
    state: present
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - auditd_audispd_disk_full_action
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Encrypt Audit Records Sent With audispd Plugin [ref]

Configure the operating system to encrypt the transfer of off-loaded audit records onto a different system or media from the system being audited. Set the transport option in

/etc/audit/audisp-remote.conf

to KRB5.

Rationale:

Information stored in one location is vulnerable to accidental or incidental deletion or alteration. Off-loading is a common process in information systems with limited audit storage capacity.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_audispd_encrypt_sent_records

References:

disa	CCI-001851
nist	AU-9(3), CM-6(a)
os-srg	SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

AUDISP_REMOTE_CONFIG="/etc/audit/audisp-remote.conf"

option="^transport"
value="KRB5"


# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "$option")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$value"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "$option\\>" "$AUDISP_REMOTE_CONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/$option\\>.*/$escaped_formatted_output/gi" "$AUDISP_REMOTE_CONFIG"
else
    if [[ -s "$AUDISP_REMOTE_CONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDISP_REMOTE_CONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDISP_REMOTE_CONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDISP_REMOTE_CONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(a)
  - auditd_audispd_encrypt_sent_records
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Configure Kerberos 5 Encryption in Audit Event Multiplexor (audispd)
  lineinfile:
    dest: /etc/audit/audisp-remote.conf
    line: enable_krb5 = yes
    regexp: ^\s*enable_krb5\s*=\s*.*$
    state: present
    mode: 416
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AU-9(3)
  - NIST-800-53-CM-6(a)
  - auditd_audispd_encrypt_sent_records
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Configure audispd's Plugin network_failure_action On Network Failure [ref]

Configure the action the operating system takes if there is an error sending audit records to a remote system. Edit the file /etc/audit/audisp-remote.conf. Add or modify the following line, substituting ACTION appropriately:

network_failure_action = ACTION

Rationale:

Taking appropriate action when there is an error sending audit records to a remote system will minimize the possibility of losing audit records.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_audispd_network_failure_action

References:

disa	CCI-001851
nist	AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a)
os-srg	SRG-OS-000342-GPOS-00133, SRG-OS-000479-GPOS-00224

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_audispd_network_failure_action='single'


AUDITCONFIG=/etc/audit/audisp-remote.conf

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^network_failure_action")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_audispd_network_failure_action"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^network_failure_action\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^network_failure_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
    if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - auditd_audispd_network_failure_action
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
- name: XCCDF Value var_audispd_network_failure_action # promote to variable
  set_fact:
    var_audispd_network_failure_action: !!str single
  tags:
    - always

- name: Make sure that network failure action is configured for Audispd
  lineinfile:
    path: /etc/audit/audisp-remote.conf
    line: network_failure_action = {{ var_audispd_network_failure_action }}
    regexp: ^\s*network_failure_action\s*=.*$
    create: true
    state: present
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - auditd_audispd_network_failure_action
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Configure auditd to use audispd's syslog plugin [ref]

To configure the auditd service to use the syslog plug-in of the audispd audit event multiplexor, set the active line in /etc/audit/plugins.d/syslog.conf to yes. Restart the auditd service:

$ sudo service auditd restart

Rationale:

The auditd service does not include the ability to send audit records to a centralized server for management directly. It does, however, include a plug-in for audit event multiplexor (audispd) to pass audit records to the local syslog server.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_audispd_syslog_plugin_activated

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01
cui	3.3.1
disa	CCI-001851
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii)
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7
nist	AU-4(1), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.5.3
os-srg	SRG-OS-000479-GPOS-00224, SRG-OS-000342-GPOS-00133
pcidss4	10.3.3, 10.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_syslog_active="yes"

AUDISP_SYSLOGCONFIG=/etc/audit/plugins.d/syslog.conf

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^active")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_syslog_active"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^active\\>" "$AUDISP_SYSLOGCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^active\\>.*/$escaped_formatted_output/gi" "$AUDISP_SYSLOGCONFIG"
else
    if [[ -s "$AUDISP_SYSLOGCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDISP_SYSLOGCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDISP_SYSLOGCONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDISP_SYSLOGCONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	configure

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-4(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.3
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.3
  - auditd_audispd_syslog_plugin_activated
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Enable syslog plugin
  lineinfile:
    dest: /etc/audit/plugins.d/syslog.conf
    regexp: ^active
    line: active = yes
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-4(1)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.5.3
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.3
  - auditd_audispd_syslog_plugin_activated
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Rule Configure auditd mail_acct Action on Low Disk Space [ref]

The auditd service can be configured to send email to a designated account in certain situations. Add or correct the following line in /etc/audit/auditd.conf to ensure that administrators are notified via email for those situations:

action_mail_acct = root

Rationale:

Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_action_mail_acct

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01
cui	3.3.1
disa	CCI-001855, CCI-000139
hipaa	164.312(a)(2)(ii)
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2
iso27001-2013	A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1
nerc-cip	CIP-003-8 R1.3, CIP-003-8 R3, CIP-003-8 R3.1, CIP-003-8 R3.2, CIP-003-8 R3.3, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3
nist	IA-5(1), AU-5(a), AU-5(2), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.7.a
os-srg	SRG-OS-000046-GPOS-00022, SRG-OS-000343-GPOS-00134

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_auditd_action_mail_acct='root'


AUDITCONFIG=/etc/audit/auditd.conf

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^action_mail_acct")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_action_mail_acct"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^action_mail_acct\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^action_mail_acct\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
    if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)
  - PCI-DSS-Req-10.7.a
  - auditd_data_retention_action_mail_acct
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_action_mail_acct # promote to variable
  set_fact:
    var_auditd_action_mail_acct: !!str root
  tags:
    - always

- name: Configure auditd mail_acct Action on Low Disk Space
  lineinfile:
    dest: /etc/audit/auditd.conf
    line: action_mail_acct = {{ var_auditd_action_mail_acct }}
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(a)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IA-5(1)
  - PCI-DSS-Req-10.7.a
  - auditd_data_retention_action_mail_acct
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure auditd admin_space_left Action on Low Disk Space [ref]

The auditd service can be configured to take an action when disk space is running low but prior to running out of space completely. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting ACTION appropriately:

admin_space_left_action = ACTION

Set this value to single to cause the system to switch to single user mode for corrective action. Acceptable values also include suspend and halt. For certain systems, the need for availability outweighs the need to log all actions, and a different setting should be determined. Details regarding all possible values for ACTION are described in the auditd.conf man page.

Rationale:

Administrators should be made aware of an inability to record audit records. If a separate partition or logical volume of adequate size is used, running low on space for audit records should never occur.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_admin_space_left_action

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01
cui	3.3.1
disa	CCI-001855
hipaa	164.312(a)(2)(ii)
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2
iso27001-2013	A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1
nist	AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.7
os-srg	SRG-OS-000343-GPOS-00134
pcidss4	10.5.1, 10.5

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_auditd_admin_space_left_action='single'


var_auditd_admin_space_left_action="$(echo $var_auditd_admin_space_left_action | cut -d \| -f 1)"

AUDITCONFIG=/etc/audit/auditd.conf

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^admin_space_left_action")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_admin_space_left_action"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^admin_space_left_action\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^admin_space_left_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
    if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - PCI-DSSv4-10.5
  - PCI-DSSv4-10.5.1
  - auditd_data_retention_admin_space_left_action
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_admin_space_left_action # promote to variable
  set_fact:
    var_auditd_admin_space_left_action: !!str single
  tags:
    - always

- name: Configure auditd admin_space_left Action on Low Disk Space
  lineinfile:
    dest: /etc/audit/auditd.conf
    line: admin_space_left_action = {{ var_auditd_admin_space_left_action .split('|')[0]
      }}
    regexp: ^\s*admin_space_left_action\s*=\s*.*$
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - PCI-DSSv4-10.5
  - PCI-DSSv4-10.5.1
  - auditd_data_retention_admin_space_left_action
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure auditd flush priority [ref]

The auditd service can be configured to synchronously write audit event data to disk. Add or correct the following line in /etc/audit/auditd.conf to ensure that audit event data is fully synchronized with the log files on the disk:

flush = data

Rationale:

Audit data should be synchronously written to disk to ensure log integrity. These parameters assure that all audit event data is fully synchronized with the log files on the disk.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_flush

References:

cis-csc	1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.3.1
disa	CCI-001576
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e)
isa-62443-2009	4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2
nerc-cip	CIP-004-6 R2.2.3, CIP-004-6 R3.3, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5
nist	AU-11, CM-6(a)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1
os-srg	SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_auditd_flush='data'


AUDITCONFIG=/etc/audit/auditd.conf

# if flush is present, flush param edited to var_auditd_flush
# else flush param is defined by var_auditd_flush
#
# the freq param is only used for values 'incremental' and 'incremental_async' and will be
# commented out if flush != incremental or flush != incremental_async
#
# if flush == incremental or flush == incremental_async && freq param is not defined, it 
# will be defined as the package-default value of 20

grep -q ^flush $AUDITCONFIG && \
  sed -i 's/^flush.*/flush = '"$var_auditd_flush"'/g' $AUDITCONFIG
if ! [ $? -eq 0 ]; then
  echo "flush = $var_auditd_flush" >> $AUDITCONFIG
fi

if ! [ "$var_auditd_flush" == "incremental" ] && ! [ "$var_auditd_flush" == "incremental_async" ]; then
  sed -i 's/^freq/##freq/g' $AUDITCONFIG
elif [ "$var_auditd_flush" == "incremental" ] || [ "$var_auditd_flush" == "incremental_async" ]; then
  grep -q freq $AUDITCONFIG && \
    sed -i 's/^#\+freq/freq/g' $AUDITCONFIG
  if ! [ $? -eq 0 ]; then
    echo "freq = 20" >> $AUDITCONFIG
  fi
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-11
  - NIST-800-53-CM-6(a)
  - auditd_data_retention_flush
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_flush # promote to variable
  set_fact:
    var_auditd_flush: !!str data
  tags:
    - always

- name: Configure auditd Flush Priority
  lineinfile:
    dest: /etc/audit/auditd.conf
    regexp: ^\s*flush\s*=\s*.*$
    line: flush = {{ var_auditd_flush }}
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-11
  - NIST-800-53-CM-6(a)
  - auditd_data_retention_flush
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure auditd Max Log File Size [ref]

Determine the amount of audit data (in megabytes) which should be retained in each log file. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting the correct value of 6 for STOREMB:

max_log_file = STOREMB

Set the value to 6 (MB) or higher for general-purpose systems. Larger values, of course, support retention of even more audit data.

Rationale:

The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_max_log_file

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7
nerc-cip	CIP-004-6 R2.2.3, CIP-004-6 R3.3, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5
nist	AU-11, CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.7

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_auditd_max_log_file='6'


AUDITCONFIG=/etc/audit/auditd.conf

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^max_log_file")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_max_log_file"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^max_log_file\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^max_log_file\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
    if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-53-AU-11
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - auditd_data_retention_max_log_file
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_max_log_file # promote to variable
  set_fact:
    var_auditd_max_log_file: !!str 6
  tags:
    - always

- name: Configure auditd Max Log File Size
  lineinfile:
    dest: /etc/audit/auditd.conf
    regexp: ^\s*max_log_file\s*=\s*.*$
    line: max_log_file = {{ var_auditd_max_log_file }}
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-53-AU-11
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - auditd_data_retention_max_log_file
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure auditd max_log_file_action Upon Reaching Maximum Log Size [ref]

The default action to take when the logs reach their maximum size is to rotate the log files, discarding the oldest one. To configure the action taken by auditd, add or correct the line in /etc/audit/auditd.conf:

max_log_file_action = ACTION

Possible values for ACTION are described in the auditd.conf man page. These include:

ignore
syslog
suspend
rotate
keep_logs

Set the ACTION to rotate. The setting is case-insensitive.

Rationale:

Automatically rotating logs (by setting this to rotate) minimizes the chances of the system unexpectedly running out of disk space by being overwhelmed with log data. However, for systems that must never discard log data, or which use external processes to transfer it and reclaim space, keep_logs can be employed.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_max_log_file_action

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01
disa	CCI-000140
hipaa	164.312(a)(2)(ii)
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2
iso27001-2013	A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1
nist	AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.7
os-srg	SRG-OS-000047-GPOS-00023

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_auditd_max_log_file_action='rotate'


AUDITCONFIG=/etc/audit/auditd.conf

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^max_log_file_action")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_max_log_file_action"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^max_log_file_action\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^max_log_file_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
    if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - auditd_data_retention_max_log_file_action
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_max_log_file_action # promote to variable
  set_fact:
    var_auditd_max_log_file_action: !!str rotate
  tags:
    - always

- name: Configure auditd max_log_file_action Upon Reaching Maximum Log Size
  lineinfile:
    dest: /etc/audit/auditd.conf
    line: max_log_file_action = {{ var_auditd_max_log_file_action }}
    regexp: ^\s*max_log_file_action\s*=\s*.*$
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - auditd_data_retention_max_log_file_action
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure auditd Number of Logs Retained [ref]

Determine how many log files auditd should retain when it rotates logs. Edit the file /etc/audit/auditd.conf. Add or modify the following line, substituting NUMLOGS with the correct value of 5:

num_logs = NUMLOGS

Set the value to 5 for general-purpose systems. Note that values less than 2 result in no log rotation.

Rationale:

The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_num_logs

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01
cui	3.3.1
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1
iso27001-2013	A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7
nerc-cip	CIP-004-6 R2.2.3, CIP-004-6 R3.3, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5
nist	AU-11, CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.7

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_auditd_num_logs='5'


AUDITCONFIG=/etc/audit/auditd.conf

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^num_logs")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_num_logs"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^num_logs\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^num_logs\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
    if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-11
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - auditd_data_retention_num_logs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_num_logs # promote to variable
  set_fact:
    var_auditd_num_logs: !!str 5
  tags:
    - always

- name: Configure auditd Number of Logs Retained
  lineinfile:
    dest: /etc/audit/auditd.conf
    line: num_logs = {{ var_auditd_num_logs }}
    regexp: ^\s*num_logs\s*=\s*.*$
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-11
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - auditd_data_retention_num_logs
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure auditd space_left on Low Disk Space [ref]

space_left = SIZE_in_MB

Set this value to the appropriate size in Megabytes cause the system to notify the user of an issue.

Rationale:

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_space_left

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8
cobit5	APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01
disa	CCI-001855
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2
iso27001-2013	A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1
nist	AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.7
os-srg	SRG-OS-000343-GPOS-00134
pcidss4	10.5.1, 10.5

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_auditd_space_left='100'


grep -q "^space_left[[:space:]]*=.*$" /etc/audit/auditd.conf && \
  sed -i "s/^space_left[[:space:]]*=.*$/space_left = $var_auditd_space_left/g" /etc/audit/auditd.conf || \
  echo "space_left = $var_auditd_space_left" >> /etc/audit/auditd.conf

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - PCI-DSSv4-10.5
  - PCI-DSSv4-10.5.1
  - auditd_data_retention_space_left
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_space_left # promote to variable
  set_fact:
    var_auditd_space_left: !!str 100
  tags:
    - always

- name: Configure auditd space_left on Low Disk Space
  lineinfile:
    dest: /etc/audit/auditd.conf
    line: space_left = {{ var_auditd_space_left }}
    regexp: ^\s*space_left\s*=\s*.*$
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - PCI-DSSv4-10.5
  - PCI-DSSv4-10.5.1
  - auditd_data_retention_space_left
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Configure auditd space_left Action on Low Disk Space [ref]

The auditd service can be configured to take an action when disk space starts to run low. Edit the file /etc/audit/auditd.conf. Modify the following line, substituting ACTION appropriately:

space_left_action = ACTION

Possible values for ACTION are described in the auditd.conf man page. These include:

syslog
email
exec
suspend
single
halt

Set this to email (instead of the default, which is suspend) as it is more likely to get prompt attention. Acceptable values also include suspend, single, and halt.

Rationale:

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_auditd_data_retention_space_left_action

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01
cui	3.3.1
disa	CCI-001855
hipaa	164.312(a)(2)(ii)
isa-62443-2009	4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2
iso27001-2013	A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1
nist	AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a)
nist-csf	DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4
pcidss	Req-10.7
os-srg	SRG-OS-000343-GPOS-00134
pcidss4	10.5.1, 10.5

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q audit && rpm --quiet -q kernel; then

var_auditd_space_left_action='email'


var_auditd_space_left_action="$(echo $var_auditd_space_left_action | cut -d \| -f 1)"
#
# If space_left_action present in /etc/audit/auditd.conf, change value
# to var_auditd_space_left_action, else
# add "space_left_action = $var_auditd_space_left_action" to /etc/audit/auditd.conf
#

AUDITCONFIG=/etc/audit/auditd.conf

# Strip any search characters in the key arg so that the key can be replaced without
# adding any search characters to the config file.
stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^space_left_action")

# shellcheck disable=SC2059
printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_space_left_action"

# If the key exists, change it. Otherwise, add it to the config_file.
# We search for the key string followed by a word boundary (matched by \>),
# so if we search for 'setting', 'setting2' won't match.
if LC_ALL=C grep -q -m 1 -i -e "^space_left_action\\>" "$AUDITCONFIG"; then
    escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
    LC_ALL=C sed -i --follow-symlinks "s/^space_left_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
else
    if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
        LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
    fi
    printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - PCI-DSSv4-10.5
  - PCI-DSSv4-10.5.1
  - auditd_data_retention_space_left_action
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_auditd_space_left_action # promote to variable
  set_fact:
    var_auditd_space_left_action: !!str email
  tags:
    - always

- name: Configure auditd space_left Action on Low Disk Space
  lineinfile:
    dest: /etc/audit/auditd.conf
    line: space_left_action = {{ var_auditd_space_left_action.split('|')[0] }}
    regexp: ^\s*space_left_action\s*=\s*.*$
    state: present
    create: true
  when:
  - '"audit" in ansible_facts.packages'
  - '"kernel" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AU-5(1)
  - NIST-800-53-AU-5(2)
  - NIST-800-53-AU-5(4)
  - NIST-800-53-AU-5(b)
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-10.7
  - PCI-DSSv4-10.5
  - PCI-DSSv4-10.5.1
  - auditd_data_retention_space_left_action
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Rule Install audispd-plugins Package [ref]

The audispd-plugins package can be installed with the following command:

$ sudo yum install audispd-plugins

Rationale:

audispd-plugins provides plugins for the real-time interface to the audit subsystem, audispd. These plugins can do things like relay events to remote machines or analyze events for suspicious behavior.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_audispd-plugins_installed

References:

disa	CCI-001851
os-srg	SRG-OS-000342-GPOS-00133
pcidss4	10.3.3, 10.3

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel; then

if ! rpm -q --quiet "audispd-plugins" ; then
    yum install -y "audispd-plugins"
fi

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲


[[packages]]
name = "audispd-plugins"
version = "*"

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.3
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_audispd-plugins_installed

- name: Ensure audispd-plugins is installed
  package:
    name: audispd-plugins
    state: present
  when: '"kernel" in ansible_facts.packages'
  tags:
  - PCI-DSSv4-10.3
  - PCI-DSSv4-10.3.3
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_audispd-plugins_installed

Remediation Anaconda snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable


package --add=audispd-plugins

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include install_audispd-plugins

class install_audispd-plugins {
  package { 'audispd-plugins':
    ensure => 'installed',
  }
}

Rule Enable auditd Service [ref]

The auditd service is an essential userspace component of the Linux Auditing System, as it is responsible for writing audit records to disk. The auditd service can be enabled with the following command:

$ sudo systemctl enable auditd.service

Rationale:

Without establishing what type of events occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Ensuring the auditd service is active ensures audit records generated by the kernel are appropriately recorded.

Additionally, a properly configured audit subsystem ensures that actions of individual system users can be uniquely traced to those users so they can be held accountable for their actions.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_auditd_enabled

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.3.1, 3.3.2, 3.3.6
disa	CCI-000133, CCI-001881, CCI-001875, CCI-000154, CCI-001882, CCI-000158, CCI-001914, CCI-000169, CCI-001464, CCI-001878, CCI-001877, CCI-001889, CCI-000135, CCI-002884, CCI-001487, CCI-003938, CCI-000132, CCI-004188, CCI-000134, CCI-000172, CCI-000130, CCI-000131, CCI-001879, CCI-001880, CCI-001876
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nerc-cip	CIP-004-6 R3.3, CIP-007-3 R6.5
nist	AC-2(g), AU-3, AU-10, AU-2(d), AU-12(c), AU-14(1), AC-6(9), CM-6(a), SI-4(23)
nist-csf	DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
ospp	FAU_GEN.1
pcidss	Req-10.1
os-srg	SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220
app-srg-ctr	SRG-APP-000095-CTR-000170, SRG-APP-000409-CTR-000990, SRG-APP-000508-CTR-001300, SRG-APP-000510-CTR-001310
anssi	R33, R73
pcidss4	10.2.1, 10.2

Remediation Shell script ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && { rpm --quiet -q audit; }; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'auditd.service'
"$SYSTEMCTL_EXEC" start 'auditd.service'
"$SYSTEMCTL_EXEC" enable 'auditd.service'

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation Kubernetes snippet ⇲

---
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
spec:
  config:
    ignition:
      version: 3.1.0
    systemd:
      units:
      - name: auditd.service
        enabled: true

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
enabled = ["auditd"]

Remediation Ansible snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-171-3.3.2
  - NIST-800-171-3.3.6
  - NIST-800-53-AC-2(g)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-10
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-14(1)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-AU-3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-4(23)
  - PCI-DSS-Req-10.1
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_auditd_enabled

- name: Enable auditd Service - Enable service auditd
  block:

  - name: Gather the package facts
    package_facts:
      manager: auto

  - name: Enable auditd Service - Enable Service auditd
    ansible.builtin.systemd:
      name: auditd
      enabled: true
      state: started
      masked: false
    when:
    - '"audit" in ansible_facts.packages'
  when:
  - '"kernel" in ansible_facts.packages'
  - '"audit" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-171-3.3.2
  - NIST-800-171-3.3.6
  - NIST-800-53-AC-2(g)
  - NIST-800-53-AC-6(9)
  - NIST-800-53-AU-10
  - NIST-800-53-AU-12(c)
  - NIST-800-53-AU-14(1)
  - NIST-800-53-AU-2(d)
  - NIST-800-53-AU-3
  - NIST-800-53-CM-6(a)
  - NIST-800-53-SI-4(23)
  - PCI-DSS-Req-10.1
  - PCI-DSSv4-10.2
  - PCI-DSSv4-10.2.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_auditd_enabled

Remediation Puppet snippet ⇲

Complexity:	low
Disruption:	low
Reboot:	false
Strategy:	enable

include enable_auditd

class enable_auditd {
  service {'auditd':
    enable => true,
    ensure => 'running',
  }
}

Rule Enable Auditing for Processes Which Start Prior to the Audit Daemon [ref]

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument audit=1 to the default GRUB 2 command line for the Linux operating system. Configure the default Grub2 kernel command line to contain audit=1 as follows:

# grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) audit=1"

Rationale:

Each process on the system carries an "auditable" flag which indicates whether its activities can be audited. Although auditd takes care of enabling this for all processes which launch after it does, adding the kernel argument ensures it is set for every process during boot.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_grub2_audit_argument

References:

cis-csc	1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8
cjis	5.4.1.1
cobit5	APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.02, DSS05.03, DSS05.04, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
cui	3.3.1
disa	CCI-000172, CCI-000130, CCI-000135, CCI-000169, CCI-002884, CCI-001464
hipaa	164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b)
isa-62443-2009	4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4
isa-62443-2013	SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 7.1, SR 7.6
iso27001-2013	A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2
nist	AC-17(1), AU-14(1), AU-10, CM-6(a), IR-5(1)
nist-csf	DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4
ospp	FAU_GEN.1
pcidss	Req-10.3
os-srg	SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000254-GPOS-00095
pcidss4	10.7.2, 10.7

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if rpm --quiet -q kernel && { rpm --quiet -q grub2-common; }; then

grubby --update-kernel=ALL --args=audit=1

else
    >&2 echo 'Remediation is not applicable, nothing was done'
fi

Remediation OSBuild Blueprint snippet ⇲

[customizations.kernel]
append = "audit=1"

Remediation Ansible snippet ⇲

Complexity:	medium
Disruption:	low
Reboot:	true
Strategy:	restrict

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-17(1)
  - NIST-800-53-AU-10
  - NIST-800-53-AU-14(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IR-5(1)
  - PCI-DSS-Req-10.3
  - PCI-DSSv4-10.7
  - PCI-DSSv4-10.7.2
  - grub2_audit_argument
  - low_disruption
  - low_severity
  - medium_complexity
  - reboot_required
  - restrict_strategy

- name: Update grub defaults and the bootloader menu
  command: /sbin/grubby --update-kernel=ALL --args="audit=1"
  when:
  - '"kernel" in ansible_facts.packages'
  - '"grub2-common" in ansible_facts.packages'
  tags:
  - CJIS-5.4.1.1
  - NIST-800-171-3.3.1
  - NIST-800-53-AC-17(1)
  - NIST-800-53-AU-10
  - NIST-800-53-AU-14(1)
  - NIST-800-53-CM-6(a)
  - NIST-800-53-IR-5(1)
  - PCI-DSS-Req-10.3
  - PCI-DSSv4-10.7
  - PCI-DSSv4-10.7.2
  - grub2_audit_argument
  - low_disruption
  - low_severity
  - medium_complexity
  - reboot_required
  - restrict_strategy

Red Hat and Red Hat Enterprise Linux are either registered trademarks or trademarks of Red Hat, Inc. in the United States and other countries. All other names are registered trademarks or trademarks of their respective companies.