Guide to the Secure Configuration of Ubuntu 22.04

with profile CIS Ubuntu 22.04 Level 1 Server Benchmark
This baseline aligns to the Center for Internet Security Ubuntu 22.04 LTS Benchmark, v1.0.0, released 08-30-2022.

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 Ubuntu 22.04. 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	CIS Ubuntu 22.04 Level 1 Server Benchmark
Profile ID	xccdf_org.ssgproject.content_profile_cis_level1_server

CPE Platforms

cpe:/o:canonical:ubuntu_linux:22.04::~~lts~~~

Revision History

Current version: 0.1.76

draft (as of 2024-11-29)

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

Checklist

Group Guide to the Secure Configuration of Ubuntu 22.04 Group contains 102 groups and 293 rules

Group System Settings Group contains 56 groups and 202 rules

[ref] Contains rules that check correct system settings.

Group Installing and Maintaining Software Group contains 9 groups and 19 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 2 groups and 5 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 1 group and 4 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 AIDE Group contains 4 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:

$ apt-get 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
stigid	UBTU-22-651010
cis	1.3.1
anssi	R76, R79
pcidss4	11.5.2
stigref	SV-260582r958944_rule

Remediation Puppet snippet ⇲

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

include install_aide

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

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
  - DISA-STIG-UBTU-22-651010
  - 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: '"linux-base" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651010
  - 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 OSBuild Blueprint snippet ⇲


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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

DEBIAN_FRONTEND=noninteractive apt-get install -y "aide"

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

Rule Build and Test AIDE Database [ref]

Run the following command to generate a new database:

$ sudo aideinit

By default, the database will be written to the file /var/lib/aide/aide.db.new. Storing the database, the configuration file /etc/aide.conf, and the binary /usr/bin/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 /var/lib/aide/aide.db

To initiate a manual check, run the following command:

$ sudo /usr/bin/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
stigid	UBTU-22-651015
cis	1.3.1
anssi	R76, R79
pcidss4	11.5.2
stigref	SV-260583r958944_rule

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
  - DISA-STIG-UBTU-22-651015
  - 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.apt:
    name: aide
    state: present
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651015
  - 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 if DB Path in /etc/aide/aide.conf Is
    Already Set
  ansible.builtin.lineinfile:
    path: /etc/aide/aide.conf
    regexp: ^#?(\s*)(database=)(.*)$
    state: absent
  check_mode: true
  changed_when: false
  register: database_replace
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651015
  - 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 if DB Out Path in /etc/aide/aide.conf
    Is Already Set
  ansible.builtin.lineinfile:
    path: /etc/aide/aide.conf
    regexp: ^#?(\s*)(database_out=)(.*)$
    state: absent
  check_mode: true
  changed_when: false
  register: database_out_replace
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651015
  - 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 - Fix DB Path in Config File if Necessary
  ansible.builtin.lineinfile:
    path: /etc/aide/aide.conf
    regexp: ^#?(\s*)(database)(\s*)=(\s*)(.*)$
    line: \2\3=\4file:/var/lib/aide/aide.db
    backrefs: true
  when:
  - '"linux-base" in ansible_facts.packages'
  - database_replace.found > 0
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651015
  - 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 - Fix DB Out Path in Config File if Necessary
  ansible.builtin.lineinfile:
    path: /etc/aide/aide.conf
    regexp: ^#?(\s*)(database_out)(\s*)=(\s*)(.*)$
    line: \2\3=\4file:/var/lib/aide/aide.db.new
    backrefs: true
  when:
  - '"linux-base" in ansible_facts.packages'
  - database_out_replace.found > 0
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651015
  - 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 the Default DB Path is Added
  ansible.builtin.lineinfile:
    path: /etc/aide/aide.conf
    line: database=file:/var/lib/aide/aide.db
    create: true
  when:
  - '"linux-base" in ansible_facts.packages'
  - database_replace.found == 0
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651015
  - 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 the Default Out Path is Added
  ansible.builtin.lineinfile:
    path: /etc/aide/aide.conf
    line: database_out=file:/var/lib/aide/aide.db.new
    create: true
  when:
  - '"linux-base" in ansible_facts.packages'
  - database_out_replace.found == 0
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651015
  - 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/aideinit -y -f
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651015
  - 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

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

DEBIAN_FRONTEND=noninteractive apt-get install -y "aide"

AIDE_CONFIG=/etc/aide/aide.conf
DEFAULT_DB_PATH=/var/lib/aide/aide.db

# Fix db path in the config file, if necessary
if ! grep -q '^database=file:' ${AIDE_CONFIG}; then
    # replace_or_append gets confused by 'database=file' as a key, so should not be used.
    #replace_or_append "${AIDE_CONFIG}" '^database=file' "${DEFAULT_DB_PATH}" '@CCENUM@' '%s:%s'
    echo "database=file:${DEFAULT_DB_PATH}" >> ${AIDE_CONFIG}
fi

# Fix db out path in the config file, if necessary
if ! grep -q '^database_out=file:' ${AIDE_CONFIG}; then
    echo "database_out=file:${DEFAULT_DB_PATH}.new" >> ${AIDE_CONFIG}
fi

/usr/sbin/aideinit -y -f

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

Rule Configure AIDE to Verify the Audit Tools [ref]

The operating system file integrity tool must be configured to protect the integrity of the audit tools.

Rationale:

Protecting the integrity of the tools used for auditing purposes is a critical step toward ensuring the integrity of audit information. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity. Audit tools include but are not limited to vendor-provided and open-source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators. It is not uncommon for attackers to replace the audit tools or inject code into the existing tools to provide the capability to hide or erase system activity from the audit logs. To address this risk, audit tools must be cryptographically signed to provide the capability to identify when the audit tools have been modified, manipulated, or replaced. An example is a checksum hash of the file or files.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_aide_check_audit_tools

References:

disa	CCI-001496, CCI-001494, CCI-001495, CCI-001493
nist	AU-9(3), AU-9(3).1
os-srg	SRG-OS-000278-GPOS-00108
stigid	UBTU-22-651030
cis	4.1.4.11
stigref	SV-260586r991567_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-651030
  - NIST-800-53-AU-9(3)
  - NIST-800-53-AU-9(3).1
  - aide_check_audit_tools
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure AIDE to Verify the Audit Tools - Gather List of Packages
  tags:
  - DISA-STIG-UBTU-22-651030
  - NIST-800-53-AU-9(3)
  - NIST-800-53-AU-9(3).1
  - aide_check_audit_tools
  - aide_check_audit_tools
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  ansible.builtin.package_facts:
    manager: auto
  when: '"linux-base" in ansible_facts.packages'

- name: Ensure aide is installed
  package:
    name: '{{ item }}'
    state: present
  with_items:
  - aide
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-651030
  - NIST-800-53-AU-9(3)
  - NIST-800-53-AU-9(3).1
  - aide_check_audit_tools
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Set audit_tools fact
  set_fact:
    audit_tools:
    - /usr/sbin/auditctl
    - /usr/sbin/auditd
    - /usr/sbin/augenrules
    - /usr/sbin/aureport
    - /usr/sbin/ausearch
    - /usr/sbin/autrace
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-651030
  - NIST-800-53-AU-9(3)
  - NIST-800-53-AU-9(3).1
  - aide_check_audit_tools
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure existing AIDE configuration for audit tools are correct
  lineinfile:
    path: /etc/aide/aide.conf
    regexp: ^{{ item }}\s
    line: '{{ item }} p+i+n+u+g+s+b+acl+xattrs+sha512'
  with_items: '{{ audit_tools }}'
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-651030
  - NIST-800-53-AU-9(3)
  - NIST-800-53-AU-9(3).1
  - aide_check_audit_tools
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Configure AIDE to properly protect audit tools
  lineinfile:
    path: /etc/aide/aide.conf
    line: '{{ item }} p+i+n+u+g+s+b+acl+xattrs+sha512'
  with_items: '{{ audit_tools }}'
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-651030
  - NIST-800-53-AU-9(3)
  - NIST-800-53-AU-9(3).1
  - aide_check_audit_tools
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

DEBIAN_FRONTEND=noninteractive apt-get install -y "aide"








if grep -i '^.*/usr/sbin/auditctl.*$' /etc/aide/aide.conf; then
sed -i "s#.*/usr/sbin/auditctl.*#/usr/sbin/auditctl p+i+n+u+g+s+b+acl+xattrs+sha512#" /etc/aide/aide.conf
else
echo "/usr/sbin/auditctl p+i+n+u+g+s+b+acl+xattrs+sha512" >> /etc/aide/aide.conf
fi

if grep -i '^.*/usr/sbin/auditd.*$' /etc/aide/aide.conf; then
sed -i "s#.*/usr/sbin/auditd.*#/usr/sbin/auditd p+i+n+u+g+s+b+acl+xattrs+sha512#" /etc/aide/aide.conf
else
echo "/usr/sbin/auditd p+i+n+u+g+s+b+acl+xattrs+sha512" >> /etc/aide/aide.conf
fi

if grep -i '^.*/usr/sbin/ausearch.*$' /etc/aide/aide.conf; then
sed -i "s#.*/usr/sbin/ausearch.*#/usr/sbin/ausearch p+i+n+u+g+s+b+acl+xattrs+sha512#" /etc/aide/aide.conf
else
echo "/usr/sbin/ausearch p+i+n+u+g+s+b+acl+xattrs+sha512" >> /etc/aide/aide.conf
fi

if grep -i '^.*/usr/sbin/aureport.*$' /etc/aide/aide.conf; then
sed -i "s#.*/usr/sbin/aureport.*#/usr/sbin/aureport p+i+n+u+g+s+b+acl+xattrs+sha512#" /etc/aide/aide.conf
else
echo "/usr/sbin/aureport p+i+n+u+g+s+b+acl+xattrs+sha512" >> /etc/aide/aide.conf
fi

if grep -i '^.*/usr/sbin/autrace.*$' /etc/aide/aide.conf; then
sed -i "s#.*/usr/sbin/autrace.*#/usr/sbin/autrace p+i+n+u+g+s+b+acl+xattrs+sha512#" /etc/aide/aide.conf
else
echo "/usr/sbin/autrace p+i+n+u+g+s+b+acl+xattrs+sha512" >> /etc/aide/aide.conf
fi

if grep -i '^.*/usr/sbin/augenrules.*$' /etc/aide/aide.conf; then
sed -i "s#.*/usr/sbin/augenrules.*#/usr/sbin/augenrules p+i+n+u+g+s+b+acl+xattrs+sha512#" /etc/aide/aide.conf
else
echo "/usr/sbin/augenrules p+i+n+u+g+s+b+acl+xattrs+sha512" >> /etc/aide/aide.conf
fi

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

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/bin/aide --config /etc/aide/aide.conf --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/bin/aide --config /etc/aide/aide.conf --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
stigid	UBTU-22-651025
cis	1.3.2
anssi	R76
pcidss4	11.5.2
stigref	SV-260585r958946_rule

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
  - DISA-STIG-UBTU-22-651025
  - 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: '"linux-base" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651025
  - 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:
  - '"linux-base" in ansible_facts.packages'
  - ansible_os_family == "RedHat" or ansible_os_family == "Suse"
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651025
  - 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:
  - '"linux-base" in ansible_facts.packages'
  - ansible_os_family == "Debian"
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651025
  - 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: '"linux-base" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651025
  - 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/bin/aide --check
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - CJIS-5.10.1.3
  - DISA-STIG-UBTU-22-651025
  - 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

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

DEBIAN_FRONTEND=noninteractive apt-get install -y "aide"

# AiDE usually adds its own cron jobs to /etc/cron.daily. If script is there, this rule is
# compliant. Otherwise, we copy the script to the /etc/cron.weekly
if ! grep -Eq '^(\/usr\/bin\/)?aide(\.wrapper)?\s+' /etc/cron.*/*; then
    cp -f /usr/share/aide/config/cron.daily/aide /etc/cron.weekly/
fi

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

Rule Package "prelink" Must not be Installed [ref]

The prelink package can be removed with the following command:

 $ apt-get remove prelink

Rationale:

The use of the prelink package can interfere with the operation of AIDE since it binaries. Prelinking can also increase damage caused by vulnerability in a common library like libc.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_prelink_removed

References:

cis	1.5.2

Remediation Puppet snippet ⇲

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

include remove_prelink

class remove_prelink {
  package { 'prelink':
    ensure => 'purged',
  }
}

Remediation Ansible snippet ⇲

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

- name: Check If Prelinked Is Installed
  ansible.builtin.stat:
    path: /usr/sbin/prelink
    get_checksum: false
  register: prelink
  tags:
  - disable_strategy
  - low_disruption
  - medium_complexity
  - medium_severity
  - no_reboot_needed
  - package_prelink_removed

- name: Restore Prelinked Binaries
  ansible.builtin.command:
    cmd: prelink -ua
  when: prelink.stat.exists
  tags:
  - disable_strategy
  - low_disruption
  - medium_complexity
  - medium_severity
  - no_reboot_needed
  - package_prelink_removed

- name: Ensure prelink is Removed
  ansible.builtin.package:
    name: prelink
    state: absent
  tags:
  - disable_strategy
  - low_disruption
  - medium_complexity
  - medium_severity
  - no_reboot_needed
  - package_prelink_removed

Remediation Shell script ⇲

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


if [[ -f /usr/sbin/prelink ]];
then
prelink -ua
fi

DEBIAN_FRONTEND=noninteractive apt-get remove -y "prelink"

Group Disk Partitioning Group contains 1 rule

[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 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
cis	1.1.2.1

Group GNOME Desktop Environment Group contains 3 groups and 8 rules

[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.

Group Configure GNOME Login Screen Group contains 2 rules

[ref] In the default GNOME desktop, the login is displayed after system boot and can display user accounts, allow users to reboot the system, and allow users to login automatically and/or with a guest account. The login screen should be configured to prevent such behavior.

For more information about enforcing preferences in the GNOME3 environment using the DConf configuration system, see https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/desktop_migration_and_administration_guide/> and the man page dconf(1).

Rule Disable the GNOME3 Login User List [ref]

In the default graphical environment, users logging directly into the system are greeted with a login screen that displays all known users. This functionality should be disabled by setting disable-user-list to true.

To disable, add or edit disable-user-list to /etc/dconf/db/gdm.d/00-security-settings. For example:

[org/gnome/login-screen]
disable-user-list=true

Once the setting has been added, add a lock to /etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification. For example:

/org/gnome/login-screen/disable-user-list

After the settings have been set, run dconf update.

Rationale:

Leaving the user list enabled is a security risk since it allows anyone with physical access to the system to quickly enumerate known user accounts without logging in.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_dconf_gnome_disable_user_list

References:

disa	CCI-000366
nist	CM-6(a), AC-23
os-srg	SRG-OS-000480-GPOS-00227
cis	1.8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)


# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                | grep -v 'distro\|ibus\|gdm.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/gdm.d/00-security-settings"
DBDIR="/etc/dconf/db/gdm.d"

mkdir -p "${DBDIR}"

# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
    if grep -q "^\\s*disable-user-list\\s*=" "${SETTINGSFILES[@]}"
    then
        
        sed -Ei "s/(^\s*)disable-user-list(\s*=)/#\1disable-user-list\2/g" "${SETTINGSFILES[@]}"
    fi
fi

[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
then
    printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
fi

escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
if grep -q "^\\s*disable-user-list\\s*=" "${DCONFFILE}"
then
        sed -i "s/\\s*disable-user-list\\s*=\\s*.*/disable-user-list=${escaped_value}/g" "${DCONFFILE}"
    else
        sed -i "\\|\\[org/gnome/login-screen\\]|a\\disable-user-list=${escaped_value}" "${DCONFFILE}"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/login-screen/disable-user-list$" "/etc/dconf/db/" \
            | grep -v 'distro\|ibus\|gdm.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/gdm.d/locks"

mkdir -p "${LOCKSFOLDER}"

# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
    sed -i -E "s|^/org/gnome/login-screen/disable-user-list$|#&|" "${LOCKFILES[@]}"
fi

if ! grep -qr "^/org/gnome/login-screen/disable-user-list$" /etc/dconf/db/gdm.d/
then
    echo "/org/gnome/login-screen/disable-user-list" >> "/etc/dconf/db/gdm.d/locks/00-security-settings-lock"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)

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

Rule Disable XDMCP in GDM [ref]

XDMCP is an unencrypted protocol, and therefore, presents a security risk, see e.g. XDMCP Gnome docs. To disable XDMCP support in Gnome, set Enable to false under the [xdmcp] configuration section in /etc/gdm/custom.conf. For example:

[xdmcp]
Enable=false

Rationale:

XDMCP provides unencrypted remote access through the Gnome Display Manager (GDM) which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to login using XDMCP, the privileged user password could be compromised due to typed XEvents and keystrokes will traversing over the network in clear text.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_gnome_gdm_disable_xdmcp

References:

cis	1.8.10

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed; then

# Try find '[xdmcp]' and 'Enable' in '/etc/gdm3/custom.conf', if it exists, set
# to 'false', if it isn't here, add it, if '[xdmcp]' doesn't exist, add it there
if grep -qzosP '[[:space:]]*\[xdmcp]([^\n\[]*\n+)+?[[:space:]]*Enable' '/etc/gdm3/custom.conf'; then
    
    sed -i "s/Enable[^(\n)]*/Enable=false/" '/etc/gdm3/custom.conf'
elif grep -qs '[[:space:]]*\[xdmcp]' '/etc/gdm3/custom.conf'; then
    sed -i "/[[:space:]]*\[xdmcp]/a Enable=false" '/etc/gdm3/custom.conf'
else
    if test -d "/etc/gdm3"; then
        printf '%s\n' '[xdmcp]' "Enable=false" >> '/etc/gdm3/custom.conf'
    else
        echo "Config file directory '/etc/gdm3' doesnt exist, not remediating, assuming non-applicability." >&2
    fi
fi

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

Group GNOME Media Settings Group contains 3 rules

[ref] GNOME media settings that apply to the graphical interface.

Rule Disable GNOME3 Automounting [ref]

The system's default desktop environment, GNOME3, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. To disable automount within GNOME3, add or set automount to false in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/media-handling]
automount=false

Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:

/org/gnome/desktop/media-handling/automount

After the settings have been set, run dconf update.

Rationale:

Disabling automatic mounting in GNOME3 can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_dconf_gnome_disable_automount

References:

cis-csc	12, 16
cobit5	APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03
cui	3.1.7
disa	CCI-000366, CCI-000778, CCI-001958
isa-62443-2009	4.3.3.2.2, 4.3.3.5.2, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.13, SR 1.2, SR 1.4, SR 1.5, SR 1.9, SR 2.1, SR 2.6
iso27001-2013	A.11.2.6, A.13.1.1, A.13.2.1, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-3, PR.AC-6
os-srg	SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227
cis	1.8.6
pcidss4	3.4.2, 3.4

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)


# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/media-handling\\]" "/etc/dconf/db/" \
                                | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"

mkdir -p "${DBDIR}"

# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
    if grep -q "^\\s*automount\\s*=" "${SETTINGSFILES[@]}"
    then
        
        sed -Ei "s/(^\s*)automount(\s*=)/#\1automount\2/g" "${SETTINGSFILES[@]}"
    fi
fi

[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/desktop/media-handling\\]" "${DCONFFILE}"
then
    printf '%s\n' "[org/gnome/desktop/media-handling]" >> ${DCONFFILE}
fi

escaped_value="$(sed -e 's/\\/\\\\/g' <<< "false")"
if grep -q "^\\s*automount\\s*=" "${DCONFFILE}"
then
        sed -i "s/\\s*automount\\s*=\\s*.*/automount=${escaped_value}/g" "${DCONFFILE}"
    else
        sed -i "\\|\\[org/gnome/desktop/media-handling\\]|a\\automount=${escaped_value}" "${DCONFFILE}"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/media-handling/automount$" "/etc/dconf/db/" \
            | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"

mkdir -p "${LOCKSFOLDER}"

# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
    sed -i -E "s|^/org/gnome/desktop/media-handling/automount$|#&|" "${LOCKFILES[@]}"
fi

if ! grep -qr "^/org/gnome/desktop/media-handling/automount$" /etc/dconf/db/local.d/
then
    echo "/org/gnome/desktop/media-handling/automount" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)

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

Rule Disable GNOME3 Automount Opening [ref]

The system's default desktop environment, GNOME3, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. To disable automount-open within GNOME3, add or set automount-open to false in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/media-handling]
automount-open=false

Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:

/org/gnome/desktop/media-handling/automount-open

After the settings have been set, run dconf update.

Rationale:

Automatically mounting file systems permits easy introduction of unknown devices, thereby facilitating malicious activity. Disabling automatic mounting in GNOME3 can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_dconf_gnome_disable_automount_open

References:

cis-csc	12, 16
cobit5	APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03
cui	3.1.7
disa	CCI-000778, CCI-000366, CCI-001958
isa-62443-2009	4.3.3.2.2, 4.3.3.5.2, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.13, SR 1.2, SR 1.4, SR 1.5, SR 1.9, SR 2.1, SR 2.6
iso27001-2013	A.11.2.6, A.13.1.1, A.13.2.1, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-3, PR.AC-6
os-srg	SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227
cis	1.8.6
pcidss4	3.4.2, 3.4

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)


# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/media-handling\\]" "/etc/dconf/db/" \
                                | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"

mkdir -p "${DBDIR}"

# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
    if grep -q "^\\s*automount-open\\s*=" "${SETTINGSFILES[@]}"
    then
        
        sed -Ei "s/(^\s*)automount-open(\s*=)/#\1automount-open\2/g" "${SETTINGSFILES[@]}"
    fi
fi

[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/desktop/media-handling\\]" "${DCONFFILE}"
then
    printf '%s\n' "[org/gnome/desktop/media-handling]" >> ${DCONFFILE}
fi

escaped_value="$(sed -e 's/\\/\\\\/g' <<< "false")"
if grep -q "^\\s*automount-open\\s*=" "${DCONFFILE}"
then
        sed -i "s/\\s*automount-open\\s*=\\s*.*/automount-open=${escaped_value}/g" "${DCONFFILE}"
    else
        sed -i "\\|\\[org/gnome/desktop/media-handling\\]|a\\automount-open=${escaped_value}" "${DCONFFILE}"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/media-handling/automount-open$" "/etc/dconf/db/" \
            | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"

mkdir -p "${LOCKSFOLDER}"

# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
    sed -i -E "s|^/org/gnome/desktop/media-handling/automount-open$|#&|" "${LOCKFILES[@]}"
fi

if ! grep -qr "^/org/gnome/desktop/media-handling/automount-open$" /etc/dconf/db/local.d/
then
    echo "/org/gnome/desktop/media-handling/automount-open" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)

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

Rule Disable GNOME3 Automount running [ref]

The system's default desktop environment, GNOME3, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. To disable autorun-never within GNOME3, add or set autorun-never to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/media-handling]
autorun-never=true

Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:

/org/gnome/desktop/media-handling/autorun-never

After the settings have been set, run dconf update.

Rationale:

Automatically mounting file systems permits easy introduction of unknown devices, thereby facilitating malicious activity. Disabling automatic mount running in GNOME3 can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_dconf_gnome_disable_autorun

References:

cis-csc	12, 16
cobit5	APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03
cui	3.1.7
disa	CCI-000366, CCI-001764, CCI-001958, CCI-000778
isa-62443-2009	4.3.3.2.2, 4.3.3.5.2, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.4
isa-62443-2013	SR 1.1, SR 1.13, SR 1.2, SR 1.4, SR 1.5, SR 1.9, SR 2.1, SR 2.6
iso27001-2013	A.11.2.6, A.13.1.1, A.13.2.1, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1
nist	CM-7(a), CM-7(b), CM-6(a)
nist-csf	PR.AC-3, PR.AC-6
os-srg	SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227
cis	1.8.8

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)


# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/media-handling\\]" "/etc/dconf/db/" \
                                | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"

mkdir -p "${DBDIR}"

# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
    if grep -q "^\\s*autorun-never\\s*=" "${SETTINGSFILES[@]}"
    then
        
        sed -Ei "s/(^\s*)autorun-never(\s*=)/#\1autorun-never\2/g" "${SETTINGSFILES[@]}"
    fi
fi

[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/desktop/media-handling\\]" "${DCONFFILE}"
then
    printf '%s\n' "[org/gnome/desktop/media-handling]" >> ${DCONFFILE}
fi

escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
if grep -q "^\\s*autorun-never\\s*=" "${DCONFFILE}"
then
        sed -i "s/\\s*autorun-never\\s*=\\s*.*/autorun-never=${escaped_value}/g" "${DCONFFILE}"
    else
        sed -i "\\|\\[org/gnome/desktop/media-handling\\]|a\\autorun-never=${escaped_value}" "${DCONFFILE}"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/media-handling/autorun-never$" "/etc/dconf/db/" \
            | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"

mkdir -p "${LOCKSFOLDER}"

# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
    sed -i -E "s|^/org/gnome/desktop/media-handling/autorun-never$|#&|" "${LOCKFILES[@]}"
fi

if ! grep -qr "^/org/gnome/desktop/media-handling/autorun-never$" /etc/dconf/db/local.d/
then
    echo "/org/gnome/desktop/media-handling/autorun-never" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)

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

Group Configure GNOME Screen Locking Group contains 2 rules

[ref] In the default GNOME3 desktop, the screen can be locked by selecting the user name in the far right corner of the main panel and selecting Lock.

The following sections detail commands to enforce idle activation of the screensaver, screen locking, a blank-screen screensaver, and an idle activation time.

Because users should be trained to lock the screen when they step away from the computer, the automatic locking feature is only meant as a backup.

The root account can be screen-locked; however, the root account should never be used to log into an X Windows environment and should only be used to for direct login via console in emergency circumstances.

For more information about enforcing preferences in the GNOME3 environment using the DConf configuration system, see http://wiki.gnome.org/dconf and the man page dconf(1).

Rule Set GNOME3 Screensaver Lock Delay After Activation Period [ref]

To activate the locking delay of the screensaver in the GNOME3 desktop when the screensaver is activated, add or set lock-delay to

uint32 0

in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/screensaver]
lock-delay=uint32 0

After the settings have been set, run dconf update.

Rationale:

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 logout because of the temporary nature of the absense.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_lock_delay

References:

cis-csc	1, 12, 15, 16
cobit5	DSS05.04, DSS05.10, DSS06.10
cui	3.1.10
disa	CCI-000057
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-11(a), CM-6(a)
nist-csf	PR.AC-7
pcidss	Req-8.1.8
os-srg	SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012
stigid	UBTU-22-271025
cis	1.8.5
pcidss4	8.2.8, 8.2
stigref	SV-260538r958402_rule

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)


var_screensaver_lock_delay='0'


# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" \
                                | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"

mkdir -p "${DBDIR}"

# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
    if grep -q "^\\s*lock-delay\\s*=" "${SETTINGSFILES[@]}"
    then
        
        sed -Ei "s/(^\s*)lock-delay(\s*=)/#\1lock-delay\2/g" "${SETTINGSFILES[@]}"
    fi
fi

[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/desktop/screensaver\\]" "${DCONFFILE}"
then
    printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
fi

escaped_value="$(sed -e 's/\\/\\\\/g' <<< "uint32 ${var_screensaver_lock_delay}")"
if grep -q "^\\s*lock-delay\\s*=" "${DCONFFILE}"
then
        sed -i "s/\\s*lock-delay\\s*=\\s*.*/lock-delay=${escaped_value}/g" "${DCONFFILE}"
    else
        sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\lock-delay=${escaped_value}" "${DCONFFILE}"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)

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

Rule Enable GNOME3 Screensaver Lock After Idle Period [ref]

To activate locking of the screensaver in the GNOME3 desktop when it is activated, add or set lock-enabled to true in /etc/dconf/db/local.d/00-security-settings. For example:

[org/gnome/desktop/screensaver]
lock-enabled=true

Once the settings have been added, add a lock to /etc/dconf/db/local.d/locks/00-security-settings-lock to prevent user modification. For example:

/org/gnome/desktop/screensaver/lock-enabled

After the settings have been set, run dconf update.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_lock_enabled

References:

cis-csc	1, 12, 15, 16
cjis	5.5.5
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
pcidss	Req-8.1.8
os-srg	SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011
stigid	UBTU-22-271020
cis	1.8.4
pcidss4	8.2.8, 8.2
stigref	SV-260537r958400_rule

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)



# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" \
                                | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
DBDIR="/etc/dconf/db/local.d"

mkdir -p "${DBDIR}"

# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
    if grep -q "^\\s*lock-enabled\\s*=" "${SETTINGSFILES[@]}"
    then
        
        sed -Ei "s/(^\s*)lock-enabled(\s*=)/#\1lock-enabled\2/g" "${SETTINGSFILES[@]}"
    fi
fi

[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/desktop/screensaver\\]" "${DCONFFILE}"
then
    printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
fi

escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
if grep -q "^\\s*lock-enabled\\s*=" "${DCONFFILE}"
then
        sed -i "s/\\s*lock-enabled\\s*=\\s*.*/lock-enabled=${escaped_value}/g" "${DCONFFILE}"
    else
        sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\lock-enabled=${escaped_value}" "${DCONFFILE}"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/desktop/screensaver/lock-enabled$" "/etc/dconf/db/" \
            | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/local.d/locks"

mkdir -p "${LOCKSFOLDER}"

# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
    sed -i -E "s|^/org/gnome/desktop/screensaver/lock-enabled$|#&|" "${LOCKFILES[@]}"
fi

if ! grep -qr "^/org/gnome/desktop/screensaver/lock-enabled$" /etc/dconf/db/local.d/
then
    echo "/org/gnome/desktop/screensaver/lock-enabled" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)

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

Rule Configure GNOME3 DConf User Profile [ref]

By default, DConf provides a standard user profile. This profile contains a list of DConf configuration databases. The user profile and database always take the highest priority. As such the DConf User profile should always exist and be configured correctly.

To make sure that the gdm profile is configured correctly, the /etc/dconf/profile/gdm should be set as follows:

user-db:user
system-db:gdm

To make sure that the user profile is configured correctly, the /etc/dconf/profile/user should be set as follows:

user-db:user
system-db:local

Rationale:

Failure to have a functional DConf profile prevents GNOME3 configuration settings from being enforced for all users and allows various security risks.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_enable_dconf_user_profile

References:

cis	1.10

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

# configure two dconf profiles:
# - gdm: required for banner/user_list settings
# - user: required for screenlock,automount,ctrlaltdel,... settings
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)

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

Group Sudo Group contains 5 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 Install sudo Package [ref]

The sudo package can be installed with the following command:

$ apt-get install sudo

Rationale:

sudo is a program designed to allow a system administrator to give limited root privileges to users and log root activity. The basic philosophy is to give as few privileges as possible but still allow system users to get their work done.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_sudo_installed

References:

disa	CCI-002235
ism	1382, 1384, 1386
nist	CM-6(a)
ospp	FMT_MOF_EXT.1
os-srg	SRG-OS-000324-GPOS-00125
cis	5.3.1
anssi	R33
pcidss4	2.2.6, 2.2

Remediation Puppet snippet ⇲

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

include install_sudo

class install_sudo {
  package { 'sudo':
    ensure => 'installed',
  }
}

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)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_sudo_installed

- name: Ensure sudo is installed
  package:
    name: sudo
    state: present
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_sudo_installed

Remediation OSBuild Blueprint snippet ⇲


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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

DEBIAN_FRONTEND=noninteractive apt-get install -y "sudo"

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

Rule Ensure Only Users Logged In To Real tty Can Execute Sudo - sudo use_pty [ref]

The sudo use_pty tag, when specified, will only execute sudo commands from users logged in to a real tty. This should be enabled by making sure that the use_pty tag exists in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/.

Rationale:

Requiring that sudo commands be run in a pseudo-terminal can prevent an attacker from retaining access to the user's terminal after the main program has finished executing.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sudo_add_use_pty

References:

pcidss	Req-10.2.5
cis	5.3.2
anssi	R39
pcidss4	2.2.6, 2.2

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_add_use_pty

- name: Ensure use_pty is enabled in /etc/sudoers
  lineinfile:
    path: /etc/sudoers
    regexp: ^[\s]*Defaults.*\buse_pty\b.*$
    line: Defaults use_pty
    validate: /usr/sbin/visudo -cf %s
  when: '"sudo" in ansible_facts.packages'
  tags:
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_add_use_pty

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'sudo' 2>/dev/null | grep -q installed; then

if /usr/sbin/visudo -qcf /etc/sudoers; then
    cp /etc/sudoers /etc/sudoers.bak
    if ! grep -P '^[\s]*Defaults[\s]*\buse_pty\b.*$' /etc/sudoers; then
        # sudoers file doesn't define Option use_pty
        echo "Defaults use_pty" >> /etc/sudoers
    fi
    
    # Check validity of sudoers and cleanup bak
    if /usr/sbin/visudo -qcf /etc/sudoers; then
        rm -f /etc/sudoers.bak
    else
        echo "Fail to validate remediated /etc/sudoers, reverting to original file."
        mv /etc/sudoers.bak /etc/sudoers
        false
    fi
else
    echo "Skipping remediation, /etc/sudoers failed to validate"
    false
fi

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

Rule Ensure Sudo Logfile Exists - sudo logfile [ref]

A custom log sudo file can be configured with the 'logfile' tag. This rule configures a sudo custom logfile at the default location suggested by CIS, which uses /var/log/sudo.log.

Rationale:

A sudo log file simplifies auditing of sudo commands.

Severity:

low

Rule ID: xccdf_org.ssgproject.content_rule_sudo_custom_logfile

References:

pcidss	Req-10.2.5
cis	5.3.3
pcidss4	2.2.6, 2.2

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_custom_logfile
- name: XCCDF Value var_sudo_logfile # promote to variable
  set_fact:
    var_sudo_logfile: !!str /var/log/sudo.log
  tags:
    - always

- name: Ensure logfile is enabled with the appropriate value in /etc/sudoers
  lineinfile:
    path: /etc/sudoers
    regexp: ^[\s]*Defaults\s(.*)\blogfile=[-]?.+\b(.*)$
    line: Defaults \1logfile={{ var_sudo_logfile }}\2
    validate: /usr/sbin/visudo -cf %s
    backrefs: true
  register: edit_sudoers_logfile_option
  when: '"sudo" in ansible_facts.packages'
  tags:
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_custom_logfile

- name: Enable logfile option with appropriate value in /etc/sudoers
  lineinfile:
    path: /etc/sudoers
    line: Defaults logfile={{ var_sudo_logfile }}
    validate: /usr/sbin/visudo -cf %s
  when:
  - '"sudo" in ansible_facts.packages'
  - edit_sudoers_logfile_option is defined and not edit_sudoers_logfile_option.changed
  tags:
  - PCI-DSS-Req-10.2.5
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - low_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_custom_logfile

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'sudo' 2>/dev/null | grep -q installed; then

var_sudo_logfile='/var/log/sudo.log'


if /usr/sbin/visudo -qcf /etc/sudoers; then
    cp /etc/sudoers /etc/sudoers.bak
    if ! grep -P '^[\s]*Defaults[\s]*\blogfile\s*=\s*(?:"?([^",\s]+)"?)\b.*$' /etc/sudoers; then
        # sudoers file doesn't define Option logfile
        echo "Defaults logfile=${var_sudo_logfile}" >> /etc/sudoers
    else
        # sudoers file defines Option logfile, remediate if appropriate value is not set
        if ! grep -P "^[\s]*Defaults.*\blogfile=${var_sudo_logfile}\b.*$" /etc/sudoers; then
            
            escaped_variable=${var_sudo_logfile//$'/'/$'\/'}
            sed -Ei "s/(^[\s]*Defaults.*\blogfile=)[-]?.+(\b.*$)/\1$escaped_variable\2/" /etc/sudoers
        fi
    fi
    
    # Check validity of sudoers and cleanup bak
    if /usr/sbin/visudo -qcf /etc/sudoers; then
        rm -f /etc/sudoers.bak
    else
        echo "Fail to validate remediated /etc/sudoers, reverting to original file."
        mv /etc/sudoers.bak /etc/sudoers
        false
    fi
else
    echo "Skipping remediation, /etc/sudoers failed to validate"
    false
fi

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

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
cis	5.3.5

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

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

Rule Require Re-Authentication When Using the sudo Command [ref]

The sudo timestamp_timeout tag sets the amount of time sudo password prompt waits. The default timestamp_timeout value is 5 minutes. The timestamp_timeout should be configured by making sure that the timestamp_timeout tag exists in /etc/sudoers configuration file or any sudo configuration snippets in /etc/sudoers.d/. If the value is set to an integer less than 0, the user's time stamp will not expire and the user will not have to re-authenticate for privileged actions until the user's session is terminated.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_sudo_require_reauthentication

References:

disa	CCI-004895
nist	IA-11
os-srg	SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158
cis	5.3.6
pcidss4	2.2.6, 2.2

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-IA-11
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_require_reauthentication
- name: XCCDF Value var_sudo_timestamp_timeout # promote to variable
  set_fact:
    var_sudo_timestamp_timeout: !!str 15
  tags:
    - always

- name: Require Re-Authentication When Using the sudo Command - Find /etc/sudoers.d/*
    files containing 'Defaults timestamp_timeout'
  ansible.builtin.find:
    path: /etc/sudoers.d
    patterns: '*'
    contains: ^[\s]*Defaults\s.*\btimestamp_timeout[\s]*=.*
  register: sudoers_d_defaults_timestamp_timeout
  when: '"sudo" in ansible_facts.packages'
  tags:
  - NIST-800-53-IA-11
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_require_reauthentication

- name: Require Re-Authentication When Using the sudo Command - Remove 'Defaults timestamp_timeout'
    from /etc/sudoers.d/* files
  ansible.builtin.lineinfile:
    path: '{{ item.path }}'
    regexp: ^[\s]*Defaults\s.*\btimestamp_timeout[\s]*=.*
    state: absent
  with_items: '{{ sudoers_d_defaults_timestamp_timeout.files }}'
  when: '"sudo" in ansible_facts.packages'
  tags:
  - NIST-800-53-IA-11
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_require_reauthentication

- name: Require Re-Authentication When Using the sudo Command - Ensure timestamp_timeout
    has the appropriate value in /etc/sudoers
  ansible.builtin.lineinfile:
    path: /etc/sudoers
    regexp: ^[\s]*Defaults\s(.*)\btimestamp_timeout[\s]*=[\s]*[-]?\w+\b(.*)$
    line: Defaults \1timestamp_timeout={{ var_sudo_timestamp_timeout }}\2
    validate: /usr/sbin/visudo -cf %s
    backrefs: true
  register: edit_sudoers_timestamp_timeout_option
  when: '"sudo" in ansible_facts.packages'
  tags:
  - NIST-800-53-IA-11
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_require_reauthentication

- name: Require Re-Authentication When Using the sudo Command - Enable timestamp_timeout
    option with correct value in /etc/sudoers
  ansible.builtin.lineinfile:
    path: /etc/sudoers
    line: Defaults timestamp_timeout={{ var_sudo_timestamp_timeout }}
    validate: /usr/sbin/visudo -cf %s
  when:
  - '"sudo" in ansible_facts.packages'
  - |
    edit_sudoers_timestamp_timeout_option is defined and not edit_sudoers_timestamp_timeout_option.changed
  tags:
  - NIST-800-53-IA-11
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_require_reauthentication

- name: Require Re-Authentication When Using the sudo Command - Remove timestamp_timeout
    wrong values in /etc/sudoers
  ansible.builtin.lineinfile:
    path: /etc/sudoers
    regexp: ^[\s]*Defaults\s.*\btimestamp_timeout[\s]*=[\s]*(?!{{ var_sudo_timestamp_timeout
      }}\b)[-]?\w+\b.*$
    state: absent
    validate: /usr/sbin/visudo -cf %s
  when: '"sudo" in ansible_facts.packages'
  tags:
  - NIST-800-53-IA-11
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - sudo_require_reauthentication

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'sudo' 2>/dev/null | grep -q installed; then

var_sudo_timestamp_timeout='15'


if grep -Px '^[\s]*Defaults.*timestamp_timeout[\s]*=.*' /etc/sudoers.d/*; then
    find /etc/sudoers.d/ -type f -exec sed -Ei "/^[[:blank:]]*Defaults.*timestamp_timeout[[:blank:]]*=.*/d" {} \;
fi

if /usr/sbin/visudo -qcf /etc/sudoers; then
    cp /etc/sudoers /etc/sudoers.bak
    if ! grep -P '^[\s]*Defaults.*timestamp_timeout[\s]*=[\s]*[-]?\w+.*$' /etc/sudoers; then
        # sudoers file doesn't define Option timestamp_timeout
        echo "Defaults timestamp_timeout=${var_sudo_timestamp_timeout}" >> /etc/sudoers
    else
        # sudoers file defines Option timestamp_timeout, remediate wrong values if present
        if grep -qP "^[\s]*Defaults\s.*\btimestamp_timeout[\s]*=[\s]*(?!${var_sudo_timestamp_timeout}\b)[-]?\w+\b.*$" /etc/sudoers; then
            sed -Ei "s/(^[[:blank:]]*Defaults.*timestamp_timeout[[:blank:]]*=)[[:blank:]]*[-]?\w+(.*$)/\1${var_sudo_timestamp_timeout}\2/" /etc/sudoers
        fi
    fi
    
    # Check validity of sudoers and cleanup bak
    if /usr/sbin/visudo -qcf /etc/sudoers; then
        rm -f /etc/sudoers.bak
    else
        echo "Fail to validate remediated /etc/sudoers, reverting to original file."
        mv /etc/sudoers.bak /etc/sudoers
        false
    fi
else
    echo "Skipping remediation, /etc/sudoers failed to validate"
    false
fi

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

Group Account and Access Control Group contains 15 groups and 64 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 Ubuntu 22.04.

Group Warning Banners for System Accesses Group contains 1 group and 14 rules

[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.

Group Implement a GUI Warning Banner Group contains 2 rules

[ref] In the default graphical environment, users logging directly into the system are greeted with a login screen provided by the GNOME Display Manager (GDM). The warning banner should be displayed in this graphical environment for these users. The following sections describe how to configure the GDM login banner.

Rule Enable GNOME3 Login Warning Banner [ref]

In the default graphical environment, displaying a login warning banner in the GNOME Display Manager's login screen can be enabled on the login screen by setting banner-message-enable to true.

To enable, add or edit banner-message-enable to /etc/dconf/db/gdm.d/00-security-settings. For example:

[org/gnome/login-screen]
banner-message-enable=true

Once the setting has been added, add a lock to /etc/dconf/db/gdm.d/locks/00-security-settings-lock to prevent user modification. For example:

/org/gnome/login-screen/banner-message-enable

After the settings have been set, run dconf update. The banner text must also be set.

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.

For U.S. Government systems, 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_dconf_gnome_banner_enabled

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(b), AC-8(c)
nist-csf	PR.AC-7
os-srg	SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088
stigid	UBTU-22-271010
cis	1.8.2
stigref	SV-260535r958390_rule

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed; then

mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
# Duplicate the setting also in 'greeter.dconf-defaults' for consistency with
# 'dconf_gnome_login_banner_text' and better alignment with STIG V1R1.
if [ -e "/etc/gdm3/greeter.dconf-defaults" ] ; then
    
    LC_ALL=C sed -i "/^\s*banner\-message\-enable/Id" "/etc/gdm3/greeter.dconf-defaults"
else
    touch "/etc/gdm3/greeter.dconf-defaults"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/gdm3/greeter.dconf-defaults"

cp "/etc/gdm3/greeter.dconf-defaults" "/etc/gdm3/greeter.dconf-defaults.bak"
# Insert after the line matching the regex '\[org/gnome/login-screen\]'
line_number="$(LC_ALL=C grep -n "\[org/gnome/login-screen\]" "/etc/gdm3/greeter.dconf-defaults.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '\[org/gnome/login-screen\]', insert at
    # the end of the file.
    printf '%s\n' "banner-message-enable=true" >> "/etc/gdm3/greeter.dconf-defaults"
else
    head -n "$(( line_number ))" "/etc/gdm3/greeter.dconf-defaults.bak" > "/etc/gdm3/greeter.dconf-defaults"
    printf '%s\n' "banner-message-enable=true" >> "/etc/gdm3/greeter.dconf-defaults"
    tail -n "+$(( line_number + 1 ))" "/etc/gdm3/greeter.dconf-defaults.bak" >> "/etc/gdm3/greeter.dconf-defaults"
fi
# Clean up after ourselves.
rm "/etc/gdm3/greeter.dconf-defaults.bak"


# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                | grep -v 'distro\|ibus\|gdm.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/gdm.d/00-security-settings"
DBDIR="/etc/dconf/db/gdm.d"

mkdir -p "${DBDIR}"

# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
    if grep -q "^\\s*banner-message-enable\\s*=" "${SETTINGSFILES[@]}"
    then
        
        sed -Ei "s/(^\s*)banner-message-enable(\s*=)/#\1banner-message-enable\2/g" "${SETTINGSFILES[@]}"
    fi
fi

[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
then
    printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
fi

escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
if grep -q "^\\s*banner-message-enable\\s*=" "${DCONFFILE}"
then
        sed -i "s/\\s*banner-message-enable\\s*=\\s*.*/banner-message-enable=${escaped_value}/g" "${DCONFFILE}"
    else
        sed -i "\\|\\[org/gnome/login-screen\\]|a\\banner-message-enable=${escaped_value}" "${DCONFFILE}"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)
# Check for setting in any of the DConf db directories
LOCKFILES=$(grep -r "^/org/gnome/login-screen/banner-message-enable$" "/etc/dconf/db/" \
            | grep -v 'distro\|ibus\|gdm.d' | grep ":" | cut -d":" -f1)
LOCKSFOLDER="/etc/dconf/db/gdm.d/locks"

mkdir -p "${LOCKSFOLDER}"

# Comment out the configurations in databases different from the target one
if [[ ! -z "${LOCKFILES}" ]]
then
    sed -i -E "s|^/org/gnome/login-screen/banner-message-enable$|#&|" "${LOCKFILES[@]}"
fi

if ! grep -qr "^/org/gnome/login-screen/banner-message-enable$" /etc/dconf/db/gdm.d/
then
    echo "/org/gnome/login-screen/banner-message-enable" >> "/etc/dconf/db/gdm.d/locks/00-security-settings-lock"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)

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

Rule Set the GNOME3 Login Warning Banner Text [ref]

In the default graphical environment, configuring the login warning banner text in the GNOME Display Manager's login screen can be configured on the login screen by setting banner-message-text to 'APPROVED_BANNER' where APPROVED_BANNER is the approved banner for your environment.

To enable, add or edit banner-message-text to /etc/gdm3/greeter.dconf-defaults. For example:

[org/gnome/login-screen]
banner-message-text='APPROVED_BANNER'

After the settings have been set, run dconf update. When entering a warning banner that spans several lines, remember to begin and end the string with ' and use \n for new lines.

Rationale:

An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_dconf_gnome_login_banner_text

References:

cis-csc	1, 12, 15, 16
cobit5	DSS05.04, DSS05.10, DSS06.10
cui	3.1.9
disa	CCI-000048, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388
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
stigid	UBTU-22-271015
cis	1.8.2
stigref	SV-260536r958390_rule

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'gdm3' 2>/dev/null | grep -q installed; then

login_banner_text='^Authorized[\s\n]+users[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.$'


# 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 newline "tokens". (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')
# 5 - Removes the newline "token." (Transforms them into newline escape sequences "\n").
#    ( Needs to be done after 4, otherwise the escapce sequence will become just "n".
login_banner_text=$(echo "$login_banner_text" | sed 's/(n)\*/\\n/g')

mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/user

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:local" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:local\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/local.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)
mkdir -p /etc/dconf/profile
dconf_profile_path=/etc/dconf/profile/gdm

[[ -s "${dconf_profile_path}" ]] || echo > "${dconf_profile_path}"

if ! grep -Pzq "(?s)^\s*user-db:user.*\n\s*system-db:gdm" "${dconf_profile_path}"; then
    sed -i --follow-symlinks "1s/^/user-db:user\nsystem-db:gdm\n/" "${dconf_profile_path}"
fi

# Make sure the corresponding directories exist
mkdir -p /etc/dconf/db/gdm.d

# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/profile
(umask 0022 && dconf update)

# Will do both approach, since we plan to migrate to checks over dconf db. That way, future updates of the tool
# will pass the check even if we decide to check only for the dconf db path.
if [ -e "/etc/gdm3/greeter.dconf-defaults" ] ; then
    
    LC_ALL=C sed -i "/^\s*banner\-message\-text/Id" "/etc/gdm3/greeter.dconf-defaults"
else
    touch "/etc/gdm3/greeter.dconf-defaults"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/gdm3/greeter.dconf-defaults"

cp "/etc/gdm3/greeter.dconf-defaults" "/etc/gdm3/greeter.dconf-defaults.bak"
# Insert after the line matching the regex '\[org/gnome/login-screen\]'
line_number="$(LC_ALL=C grep -n "\[org/gnome/login-screen\]" "/etc/gdm3/greeter.dconf-defaults.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '\[org/gnome/login-screen\]', insert at
    # the end of the file.
    printf '%s\n' "banner-message-text='${login_banner_text}'" >> "/etc/gdm3/greeter.dconf-defaults"
else
    head -n "$(( line_number ))" "/etc/gdm3/greeter.dconf-defaults.bak" > "/etc/gdm3/greeter.dconf-defaults"
    printf '%s\n' "banner-message-text='${login_banner_text}'" >> "/etc/gdm3/greeter.dconf-defaults"
    tail -n "+$(( line_number + 1 ))" "/etc/gdm3/greeter.dconf-defaults.bak" >> "/etc/gdm3/greeter.dconf-defaults"
fi
# Clean up after ourselves.
rm "/etc/gdm3/greeter.dconf-defaults.bak"
# Check for setting in any of the DConf db directories
# If files contain ibus or distro, ignore them.
# The assignment assumes that individual filenames don't contain :
readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                | grep -v 'distro\|ibus\|gdm.d' | cut -d":" -f1)
DCONFFILE="/etc/dconf/db/gdm.d/00-security-settings"
DBDIR="/etc/dconf/db/gdm.d"

mkdir -p "${DBDIR}"

# Comment out the configurations in databases different from the target one
if [ "${#SETTINGSFILES[@]}" -ne 0 ]
then
    if grep -q "^\\s*banner-message-text\\s*=" "${SETTINGSFILES[@]}"
    then
        
        sed -Ei "s/(^\s*)banner-message-text(\s*=)/#\1banner-message-text\2/g" "${SETTINGSFILES[@]}"
    fi
fi

[ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
then
    printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
fi

escaped_value="$(sed -e 's/\\/\\\\/g' <<< "'${login_banner_text}'")"
if grep -q "^\\s*banner-message-text\\s*=" "${DCONFFILE}"
then
        sed -i "s/\\s*banner-message-text\\s*=\\s*.*/banner-message-text=${escaped_value}/g" "${DCONFFILE}"
    else
        sed -i "\\|\\[org/gnome/login-screen\\]|a\\banner-message-text=${escaped_value}" "${DCONFFILE}"
fi
# Make sure permissions allow regular users to read dconf settings.
# Also define the umask to avoid `dconf update` changing permissions.
chmod -R u=rwX,go=rX /etc/dconf/db
(umask 0022 && dconf update)
# No need to use dconf update, since bash_dconf_settings does that already

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

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
cis	1.7.2

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

login_banner_text='^Authorized[\s\n]+users[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.$'


# 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

Rule Modify the System Login Banner for Remote Connections [ref]

To configure the system login banner edit /etc/issue.net. 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_net

References:

disa	CCI-000048, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388
os-srg	SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088
stigid	UBTU-22-255020
cis	1.7.3
stigref	SV-260525r958390_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-255020
  - banner_etc_issue_net
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy
- name: XCCDF Value remote_login_banner_text # promote to variable
  set_fact:
    remote_login_banner_text: !!str ^Authorized[\s\n]+uses[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.$
  tags:
    - always

- name: Modify the System Login Banner for Remote Connections - ensure correct banner
  copy:
    dest: /etc/issue.net
    content: '{{ remote_login_banner_text | regex_replace("^\^(.*)\$$", "\1") | regex_replace("^\((.*\.)\|.*\)$",
      "\1") | regex_replace("\[\\s\\n\]\+"," ") | regex_replace("\(\?:\[\\n\]\+\|\(\?:\\\\n\)\+\)",
      "\n") | regex_replace("\\", "") | wordwrap() }}'
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-255020
  - banner_etc_issue_net
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - unknown_strategy

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

remote_login_banner_text='^Authorized[\s\n]+uses[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.$'


# Multiple regexes transform the banner regex into a usable banner
# 0 - Remove anchors around the banner text
remote_login_banner_text=$(echo "$remote_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)
remote_login_banner_text=$(echo "$remote_login_banner_text" | sed 's/^(\(.*\.\)|.*)$/\1/g')
# 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
remote_login_banner_text=$(echo "$remote_login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
# 3 - Adds newlines. (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "\n")
remote_login_banner_text=$(echo "$remote_login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\\\n)+)/\n/g')
# 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
remote_login_banner_text=$(echo "$remote_login_banner_text" | sed 's/\\//g')
formatted=$(echo "$remote_login_banner_text" | fold -sw 80)

cat <<EOF >/etc/issue.net
$formatted
EOF

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

Rule Modify the System Message of the Day Banner [ref]

To configure the system message banner edit /etc/motd. 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_motd

References:

cis	1.7.1

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

motd_banner_text='^Authorized[\s\n]+uses[\s\n]+only\.[\s\n]+All[\s\n]+activity[\s\n]+may[\s\n]+be[\s\n]+monitored[\s\n]+and[\s\n]+reported\.$'


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

cat <<EOF >/etc/motd
$formatted
EOF

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

Rule Verify Group Ownership of System Login Banner [ref]

To properly set the group owner of /etc/issue, run the command:

$ sudo chgrp root /etc/issue

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.
Proper group ownership will ensure that only root user can modify the banner.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_groupowner_etc_issue

References:

cis	1.7.5

Remediation Ansible snippet ⇲

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

- name: Test for existence /etc/issue
  stat:
    path: /etc/issue
  register: file_exists
  tags:
  - configure_strategy
  - file_groupowner_etc_issue
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure group owner 0 on /etc/issue
  file:
    path: /etc/issue
    group: '0'
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - configure_strategy
  - file_groupowner_etc_issue
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Shell script ⇲

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

chgrp 0 /etc/issue

Rule Verify Group Ownership of System Login Banner for Remote Connections [ref]

To properly set the group owner of /etc/issue.net, run the command:

$ sudo chgrp root /etc/issue.net

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.
Proper group ownership will ensure that only root user can modify the banner.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_groupowner_etc_issue_net

References:

cis	1.7.6
pcidss4	1.2.8, 1.2

Remediation Ansible snippet ⇲

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

- name: Test for existence /etc/issue.net
  stat:
    path: /etc/issue.net
  register: file_exists
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.8
  - configure_strategy
  - file_groupowner_etc_issue_net
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure group owner 0 on /etc/issue.net
  file:
    path: /etc/issue.net
    group: '0'
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.8
  - configure_strategy
  - file_groupowner_etc_issue_net
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Shell script ⇲

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

chgrp 0 /etc/issue.net

Rule Verify Group Ownership of Message of the Day Banner [ref]

To properly set the group owner of /etc/motd, run the command:

$ sudo chgrp root /etc/motd

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.
Proper group ownership will ensure that only root user can modify the banner.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_groupowner_etc_motd

References:

cis	1.7.4

Remediation Ansible snippet ⇲

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

- name: Test for existence /etc/motd
  stat:
    path: /etc/motd
  register: file_exists
  tags:
  - configure_strategy
  - file_groupowner_etc_motd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure group owner 0 on /etc/motd
  file:
    path: /etc/motd
    group: '0'
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - configure_strategy
  - file_groupowner_etc_motd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Shell script ⇲

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

chgrp 0 /etc/motd

Rule Verify ownership of System Login Banner [ref]

To properly set the owner of /etc/issue, run the command:

$ sudo chown root /etc/issue

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.
Proper ownership will ensure that only root user can modify the banner.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_owner_etc_issue

References:

cis	1.7.5

Remediation Ansible snippet ⇲

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

- name: Test for existence /etc/issue
  stat:
    path: /etc/issue
  register: file_exists
  tags:
  - configure_strategy
  - file_owner_etc_issue
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure owner 0 on /etc/issue
  file:
    path: /etc/issue
    owner: '0'
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - configure_strategy
  - file_owner_etc_issue
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Shell script ⇲

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

chown 0 /etc/issue

Rule Verify ownership of System Login Banner for Remote Connections [ref]

To properly set the owner of /etc/issue.net, run the command:

$ sudo chown root /etc/issue.net

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.
Proper ownership will ensure that only root user can modify the banner.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_owner_etc_issue_net

References:

cis	1.7.6
pcidss4	1.2.8, 1.2

Remediation Ansible snippet ⇲

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

- name: Test for existence /etc/issue.net
  stat:
    path: /etc/issue.net
  register: file_exists
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.8
  - configure_strategy
  - file_owner_etc_issue_net
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure owner 0 on /etc/issue.net
  file:
    path: /etc/issue.net
    owner: '0'
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.8
  - configure_strategy
  - file_owner_etc_issue_net
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Shell script ⇲

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

chown 0 /etc/issue.net

Rule Verify ownership of Message of the Day Banner [ref]

To properly set the owner of /etc/motd, run the command:

$ sudo chown root /etc/motd

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.
Proper ownership will ensure that only root user can modify the banner.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_owner_etc_motd

References:

cis	1.7.4

Remediation Ansible snippet ⇲

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

- name: Test for existence /etc/motd
  stat:
    path: /etc/motd
  register: file_exists
  tags:
  - configure_strategy
  - file_owner_etc_motd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure owner 0 on /etc/motd
  file:
    path: /etc/motd
    owner: '0'
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - configure_strategy
  - file_owner_etc_motd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Shell script ⇲

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

chown 0 /etc/motd

Rule Verify permissions on System Login Banner [ref]

To properly set the permissions of /etc/issue, run the command:

$ sudo chmod 0644 /etc/issue

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.
Proper permissions will ensure that only root user can modify the banner.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permissions_etc_issue

References:

cis	1.7.5

Remediation Ansible snippet ⇲

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

- name: Test for existence /etc/issue
  stat:
    path: /etc/issue
  register: file_exists
  tags:
  - configure_strategy
  - file_permissions_etc_issue
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure permission u-xs,g-xws,o-xwt on /etc/issue
  file:
    path: /etc/issue
    mode: u-xs,g-xws,o-xwt
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - configure_strategy
  - file_permissions_etc_issue
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Shell script ⇲

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





chmod u-xs,g-xws,o-xwt /etc/issue

Rule Verify permissions on System Login Banner for Remote Connections [ref]

To properly set the permissions of /etc/issue.net, run the command:

$ sudo chmod 0644 /etc/issue.net

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.
Proper permissions will ensure that only root user can modify the banner.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permissions_etc_issue_net

References:

cis	1.7.6
pcidss4	1.2.8, 1.2

Remediation Ansible snippet ⇲

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

- name: Test for existence /etc/issue.net
  stat:
    path: /etc/issue.net
  register: file_exists
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.8
  - configure_strategy
  - file_permissions_etc_issue_net
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure permission u-xs,g-xws,o-xwt on /etc/issue.net
  file:
    path: /etc/issue.net
    mode: u-xs,g-xws,o-xwt
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - PCI-DSSv4-1.2
  - PCI-DSSv4-1.2.8
  - configure_strategy
  - file_permissions_etc_issue_net
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Shell script ⇲

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





chmod u-xs,g-xws,o-xwt /etc/issue.net

Rule Verify permissions on Message of the Day Banner [ref]

To properly set the permissions of /etc/motd, run the command:

$ sudo chmod 0644 /etc/motd

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.
Proper permissions will ensure that only root user can modify the banner.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_file_permissions_etc_motd

References:

cis	1.7.4

Remediation Ansible snippet ⇲

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

- name: Test for existence /etc/motd
  stat:
    path: /etc/motd
  register: file_exists
  tags:
  - configure_strategy
  - file_permissions_etc_motd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure permission u-xs,g-xws,o-xwt on /etc/motd
  file:
    path: /etc/motd
    mode: u-xs,g-xws,o-xwt
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - configure_strategy
  - file_permissions_etc_motd
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

Remediation Shell script ⇲

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





chmod u-xs,g-xws,o-xwt /etc/motd

Group Protect Accounts by Configuring PAM Group contains 4 groups and 13 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 4 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: 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.

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
cis	5.4.3
anssi	R31
pcidss4	8.3.7, 8.3

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 the required PAM module option is present
    in /etc/pam.d/common-password
  ansible.builtin.lineinfile:
    path: /etc/pam.d/common-password
    regexp: ^\s*password\s+\[success=[A-Za-z0-9].*\]\s+pam_unix.so\s*.*\sremember\b
    state: absent
  check_mode: true
  changed_when: false
  register: result_pam_module_remember_option_present
  when: '"libpam-runtime" 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 - Ensure the "remember" PAM option for "pam_unix.so"
    is included in /etc/pam.d/common-password
  ansible.builtin.lineinfile:
    path: /etc/pam.d/common-password
    backrefs: true
    regexp: ^(\s*password\s+\[success=[A-Za-z0-9].*\]\s+pam_unix.so.*)
    line: \1 remember={{ var_password_pam_unix_remember }}
    state: present
  register: result_pam_remember_add
  when:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_pam_module_remember_option_present.found == 0
  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 - Ensure the required value for "remember" PAM option
    from "pam_unix.so" in /etc/pam.d/common-password
  ansible.builtin.lineinfile:
    path: /etc/pam.d/common-password
    backrefs: true
    regexp: ^(\s*password\s+\[success=[A-Za-z0-9].*\]\s+pam_unix.so\s+.*)(remember)=[0-9a-zA-Z]+\s*(.*)
    line: \1\2={{ var_password_pam_unix_remember }} \3
  register: result_pam_remember_edit
  when:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_pam_module_remember_option_present.found > 0
  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

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; then

var_password_pam_unix_remember='5'






if [ -e "/etc/pam.d/common-password" ] ; then
    valueRegex="$var_password_pam_unix_remember" defaultValue="$var_password_pam_unix_remember"
    # non-empty values need to be preceded by an equals sign
    [ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
    # add an equals sign to non-empty values
    [ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"

    # fix 'type' if it's wrong
    if grep -q -P "^\\s*(?"'!'"password\\s)[[:alnum:]]+\\s+[[:alnum:]]+\\s+pam_unix.so" < "/etc/pam.d/common-password" ; then
        sed --follow-symlinks -i -E -e "s/^(\\s*)[[:alnum:]]+(\\s+[[:alnum:]]+\\s+pam_unix.so)/\\1password\\2/" "/etc/pam.d/common-password"
    fi

    # fix 'control' if it's wrong
    if grep -q -P "^\\s*password\\s+(?"'!'"\[success=[[:alnum:]].*\])[[:alnum:]]+\\s+pam_unix.so" < "/etc/pam.d/common-password" ; then
        sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+)[[:alnum:]]+(\\s+pam_unix.so)/\\1\[success=[[:alnum:]].*\]\\2/" "/etc/pam.d/common-password"
    fi

    # fix the value for 'option' if one exists but does not match 'valueRegex'
    if grep -q -P "^\\s*password\\s+\[success=[[:alnum:]].*\]\\s+pam_unix.so(\\s.+)?\\s+remember(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-password" ; then
        sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+\[success=[[:alnum:]].*\]\\s+pam_unix.so(\\s.+)?\\s)remember=[^[:space:]]*/\\1remember${defaultValue}/" "/etc/pam.d/common-password"

    # add 'option=default' if option is not set
    elif grep -q -E "^\\s*password\\s+\[success=[[:alnum:]].*\]\\s+pam_unix.so" < "/etc/pam.d/common-password" &&
            grep    -E "^\\s*password\\s+\[success=[[:alnum:]].*\]\\s+pam_unix.so" < "/etc/pam.d/common-password" | grep -q -E -v "\\sremember(=|\\s|\$)" ; then

        sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+\[success=[[:alnum:]].*\]\\s+pam_unix.so[^\\n]*)/\\1 remember${defaultValue}/" "/etc/pam.d/common-password"
    # add a new entry if none exists
    elif ! grep -q -P "^\\s*password\\s+\[success=[[:alnum:]].*\]\\s+pam_unix.so(\\s.+)?\\s+remember${valueRegex}(\\s|\$)" < "/etc/pam.d/common-password" ; then
        echo "password \[success=[[:alnum:]].*\] pam_unix.so remember${defaultValue}" >> "/etc/pam.d/common-password"
    fi
else
    echo "/etc/pam.d/common-password doesn't exist" >&2
fi

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

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 4 and greater than 0.

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
stigid	UBTU-22-411045
cis	5.4.2
anssi	R31
pcidss4	8.3.4, 8.3
stigref	SV-260549r958388_rule

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
  - DISA-STIG-UBTU-22-411045
  - 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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - not result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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 4
  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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - not result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; then

var_accounts_passwords_pam_faillock_deny='4'


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
    
pam_file="/etc/pam.d/common-auth"
if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+preauth.*$' "$pam_file" ; then
    # insert at the top
    sed -i --follow-symlinks '/^# here are the per-package modules/i auth        required      pam_faillock.so preauth' "$pam_file"
fi
if ! grep -qE '^\s*auth\s+\[default=die\]\s+pam_faillock\.so\s+authfail.*$' "$pam_file" ; then

    num_lines=$(sed -n 's/^\s*auth.*success=\([1-9]\).*pam_unix\.so.*/\1/p' "$pam_file")
    if [ ! -z "$num_lines" ]; then

        # Add pam_faillock (authfail) module below pam_unix, skipping N-1 lines, where N is
        # the number of jumps in the pam_unix success=N statement. Ignore commented and empty lines.

        append_position=$(cat -n "${pam_file}" \
                          | grep -P "^\s+\d+\s+auth\s+.*$" \
                          | grep -w "pam_unix.so" -A $(( num_lines - 1 )) \
                          | tail -n 1 | cut -f 1 | tr -d ' '
                         )
        sed -i --follow-symlinks ''${append_position}'a auth        [default=die]      pam_faillock.so authfail' "$pam_file"
    else
        sed -i --follow-symlinks '/^auth.*pam_unix\.so.*/a auth        [default=die]      pam_faillock.so authfail' "$pam_file"
    fi
fi
if ! grep -qE '^\s*auth\s+sufficient\s+pam_faillock\.so\s+authsucc.*$' "$pam_file" ; then
    sed -i --follow-symlinks '/^auth.*pam_faillock\.so.*authfail.*/a auth        sufficient      pam_faillock.so authsucc' "$pam_file"
fi

pam_file="/etc/pam.d/common-account"
if ! grep -qE '^\s*account\s+required\s+pam_faillock\.so.*$' "$pam_file" ; then
    echo 'account   required     pam_faillock.so' >> "$pam_file"
fi

fi

AUTH_FILES=("/etc/pam.d/common-auth")

FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ]; 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

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.

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
stigid	UBTU-22-411045
cis	5.4.2
anssi	R31
stigref	SV-260549r958388_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-411045
  - 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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - not result_authselect_present.stat.exists
  tags:
  - DISA-STIG-UBTU-22-411045
  - 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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - not result_faillock_conf_check.stat.exists
  tags:
  - DISA-STIG-UBTU-22-411045
  - 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

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; 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
    
pam_file="/etc/pam.d/common-auth"
if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+preauth.*$' "$pam_file" ; then
    # insert at the top
    sed -i --follow-symlinks '/^# here are the per-package modules/i auth        required      pam_faillock.so preauth' "$pam_file"
fi
if ! grep -qE '^\s*auth\s+\[default=die\]\s+pam_faillock\.so\s+authfail.*$' "$pam_file" ; then

    num_lines=$(sed -n 's/^\s*auth.*success=\([1-9]\).*pam_unix\.so.*/\1/p' "$pam_file")
    if [ ! -z "$num_lines" ]; then

        # Add pam_faillock (authfail) module below pam_unix, skipping N-1 lines, where N is
        # the number of jumps in the pam_unix success=N statement. Ignore commented and empty lines.

        append_position=$(cat -n "${pam_file}" \
                          | grep -P "^\s+\d+\s+auth\s+.*$" \
                          | grep -w "pam_unix.so" -A $(( num_lines - 1 )) \
                          | tail -n 1 | cut -f 1 | tr -d ' '
                         )
        sed -i --follow-symlinks ''${append_position}'a auth        [default=die]      pam_faillock.so authfail' "$pam_file"
    else
        sed -i --follow-symlinks '/^auth.*pam_unix\.so.*/a auth        [default=die]      pam_faillock.so authfail' "$pam_file"
    fi
fi
if ! grep -qE '^\s*auth\s+sufficient\s+pam_faillock\.so\s+authsucc.*$' "$pam_file" ; then
    sed -i --follow-symlinks '/^auth.*pam_faillock\.so.*authfail.*/a auth        sufficient      pam_faillock.so authsucc' "$pam_file"
fi

pam_file="/etc/pam.d/common-account"
if ! grep -qE '^\s*account\s+required\s+pam_faillock\.so.*$' "$pam_file" ; then
    echo 'account   required     pam_faillock.so' >> "$pam_file"
fi

fi

AUTH_FILES=("/etc/pam.d/common-auth")

FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ]; 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

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 600 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
stigid	UBTU-22-411045
cis	5.4.2
anssi	R31
pcidss4	8.3.4, 8.3
stigref	SV-260549r958388_rule

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
  - DISA-STIG-UBTU-22-411045
  - 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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - not result_authselect_present.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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 600
  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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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:
  - '"libpam-runtime" in ansible_facts.packages'
  - not result_faillock_conf_check.stat.exists
  tags:
  - CJIS-5.5.3
  - DISA-STIG-UBTU-22-411045
  - 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

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; then

var_accounts_passwords_pam_faillock_unlock_time='600'


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
    
pam_file="/etc/pam.d/common-auth"
if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+preauth.*$' "$pam_file" ; then
    # insert at the top
    sed -i --follow-symlinks '/^# here are the per-package modules/i auth        required      pam_faillock.so preauth' "$pam_file"
fi
if ! grep -qE '^\s*auth\s+\[default=die\]\s+pam_faillock\.so\s+authfail.*$' "$pam_file" ; then

    num_lines=$(sed -n 's/^\s*auth.*success=\([1-9]\).*pam_unix\.so.*/\1/p' "$pam_file")
    if [ ! -z "$num_lines" ]; then

        # Add pam_faillock (authfail) module below pam_unix, skipping N-1 lines, where N is
        # the number of jumps in the pam_unix success=N statement. Ignore commented and empty lines.

        append_position=$(cat -n "${pam_file}" \
                          | grep -P "^\s+\d+\s+auth\s+.*$" \
                          | grep -w "pam_unix.so" -A $(( num_lines - 1 )) \
                          | tail -n 1 | cut -f 1 | tr -d ' '
                         )
        sed -i --follow-symlinks ''${append_position}'a auth        [default=die]      pam_faillock.so authfail' "$pam_file"
    else
        sed -i --follow-symlinks '/^auth.*pam_unix\.so.*/a auth        [default=die]      pam_faillock.so authfail' "$pam_file"
    fi
fi
if ! grep -qE '^\s*auth\s+sufficient\s+pam_faillock\.so\s+authsucc.*$' "$pam_file" ; then
    sed -i --follow-symlinks '/^auth.*pam_faillock\.so.*authfail.*/a auth        sufficient      pam_faillock.so authsucc' "$pam_file"
fi

pam_file="/etc/pam.d/common-account"
if ! grep -qE '^\s*account\s+required\s+pam_faillock\.so.*$' "$pam_file" ; then
    echo 'account   required     pam_faillock.so' >> "$pam_file"
fi

fi

AUTH_FILES=("/etc/pam.d/common-auth")

FAILLOCK_CONF="/etc/security/faillock.conf"
if [ -f $FAILLOCK_CONF ]; 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

Group Set Password Quality Requirements Group contains 1 group and 7 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 7 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
stigid	UBTU-22-611020
cis	5.4.1
anssi	R31
pcidss4	8.3.6, 8.3
stigref	SV-260562r986287_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-611020
  - 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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-611020
  - 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; 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

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
stigid	UBTU-22-611015
cis	5.4.1
anssi	R31
pcidss4	8.3.6, 8.3
stigref	SV-260561r986286_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-611015
  - 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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-611015
  - 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; 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

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
cis	5.4.1
anssi	R68

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: '"libpam-runtime" 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; 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

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=14

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
stigid	UBTU-22-611035
cis	5.4.1
anssi	R31, R68
pcidss4	8.3.6, 8.3
stigref	SV-260565r986289_rule

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
  - DISA-STIG-UBTU-22-611035
  - 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 14
  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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - CJIS-5.6.2.1.1
  - DISA-STIG-UBTU-22-611035
  - 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; then

var_password_pam_minlen='14'






# 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

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
stigid	UBTU-22-611025
cis	5.4.1
anssi	R31
stigref	SV-260563r991561_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-611025
  - 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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-611025
  - 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; 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

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/common-password 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
stigid	UBTU-22-611045
cis	5.4.1
anssi	R68
stigref	SV-260567r991587_rule

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; then

var_password_pam_retry='3'


if [ -e "/etc/pam.d/common-password" ] ; then
    valueRegex="$var_password_pam_retry" defaultValue="$var_password_pam_retry"
    # non-empty values need to be preceded by an equals sign
    [ -n "${valueRegex}" ] && valueRegex="=${valueRegex}"
    # add an equals sign to non-empty values
    [ -n "${defaultValue}" ] && defaultValue="=${defaultValue}"

    # fix 'type' if it's wrong
    if grep -q -P "^\\s*(?"'!'"password\\s)[[:alnum:]]+\\s+[[:alnum:]]+\\s+pam_pwquality.so" < "/etc/pam.d/common-password" ; then
        sed --follow-symlinks -i -E -e "s/^(\\s*)[[:alnum:]]+(\\s+[[:alnum:]]+\\s+pam_pwquality.so)/\\1password\\2/" "/etc/pam.d/common-password"
    fi

    # fix 'control' if it's wrong
    if grep -q -P "^\\s*password\\s+(?"'!'"requisite)[[:alnum:]]+\\s+pam_pwquality.so" < "/etc/pam.d/common-password" ; then
        sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+)[[:alnum:]]+(\\s+pam_pwquality.so)/\\1requisite\\2/" "/etc/pam.d/common-password"
    fi

    # fix the value for 'option' if one exists but does not match 'valueRegex'
    if grep -q -P "^\\s*password\\s+requisite\\s+pam_pwquality.so(\\s.+)?\\s+retry(?"'!'"${valueRegex}(\\s|\$))" < "/etc/pam.d/common-password" ; then
        sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_pwquality.so(\\s.+)?\\s)retry=[^[:space:]]*/\\1retry${defaultValue}/" "/etc/pam.d/common-password"

    # add 'option=default' if option is not set
    elif grep -q -E "^\\s*password\\s+requisite\\s+pam_pwquality.so" < "/etc/pam.d/common-password" &&
            grep    -E "^\\s*password\\s+requisite\\s+pam_pwquality.so" < "/etc/pam.d/common-password" | grep -q -E -v "\\sretry(=|\\s|\$)" ; then

        sed --follow-symlinks -i -E -e "s/^(\\s*password\\s+requisite\\s+pam_pwquality.so[^\\n]*)/\\1 retry${defaultValue}/" "/etc/pam.d/common-password"
    # add a new entry if none exists
    elif ! grep -q -P "^\\s*password\\s+requisite\\s+pam_pwquality.so(\\s.+)?\\s+retry${valueRegex}(\\s|\$)" < "/etc/pam.d/common-password" ; then
        echo "password requisite pam_pwquality.so retry${defaultValue}" >> "/etc/pam.d/common-password"
    fi
else
    echo "/etc/pam.d/common-password doesn't exist" >&2
fi

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

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
stigid	UBTU-22-611010
cis	5.4.1
anssi	R31
stigref	SV-260560r986285_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-611010
  - 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: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-611010
  - 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; 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

Group Set Password Hashing Algorithm Group contains 1 rule

[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/login.defs [ref]

In /etc/login.defs, add or update the following line to ensure the system will use YESCRYPT as the hashing algorithm:

ENCRYPT_METHOD YESCRYPT

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.

Using a stronger hashing algorithm makes password cracking attacks more difficult.

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
stigid	UBTU-22-611070
cis	5.4.4
pcidss4	8.3.2, 8.3
stigref	SV-260572r971535_rule

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'login' 2>/dev/null | grep -q installed; then

var_password_hashing_algorithm='YESCRYPT'

# 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

Rule Install pam_pwquality Package [ref]

The libpam-pwquality package can be installed with the following command:

$ apt-get install libpam-pwquality

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. "pwquality" enforces complex password construction configuration and has the ability to limit brute-force attacks on the system.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_pam_pwquality_installed

References:

disa	CCI-000366
os-srg	SRG-OS-000480-GPOS-00225
stigid	UBTU-22-215010
cis	5.4.1
stigref	SV-260478r991587_rule

Remediation Puppet snippet ⇲

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

include install_libpam-pwquality

class install_libpam-pwquality {
  package { 'libpam-pwquality':
    ensure => 'installed',
  }
}

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-215010
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_pam_pwquality_installed

- name: Ensure libpam-pwquality is installed
  package:
    name: libpam-pwquality
    state: present
  when: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-215010
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_pam_pwquality_installed

Remediation OSBuild Blueprint snippet ⇲


[[packages]]
name = "libpam-pwquality"
version = "*"

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; then

DEBIAN_FRONTEND=noninteractive apt-get install -y "libpam-pwquality"

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

Group Protect Accounts by Restricting Password-Based Login Group contains 4 groups and 23 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 3 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=30

If a password is currently on the verge of expiration, then 30 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 30 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
stigid	UBTU-22-411035
cis	5.5.1.4
pcidss4	8.2.6, 8.2
stigref	SV-260547r986282_rule

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'login' 2>/dev/null | grep -q installed; then

var_account_disable_post_pw_expiration='30'


# 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

Rule Ensure All Accounts on the System Have Unique Names [ref]

Ensure accounts on the system have unique names. To ensure all accounts have unique names, run the following command:

$ sudo getent passwd | awk -F: '{ print $1}' | uniq -d

If a username is returned, change or delete the username.

Rationale:

Unique usernames allow for accountability on the system.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_account_unique_name

References:

cjis	5.5.2
disa	CCI-000770, CCI-000804
pcidss	Req-8.1.1
cis	6.2.7
pcidss4	8.2.1, 8.2

Rule Ensure shadow Group is Empty [ref]

The shadow group allows system programs which require access the ability to read the /etc/shadow file. No users should be assigned to the shadow group.

Warning: This rule remediation will ensure the group membership is empty in /etc/group. To avoid any disruption the remediation won't change the primary group of users in /etc/passwd if any user has the shadow GID as primary group.

Rationale:

Any users assigned to the shadow group would be granted read access to the /etc/shadow file. If attackers can gain read access to the /etc/shadow file, they can easily run a password cracking program against the hashed passwords to break them. Other security information that is stored in the /etc/shadow file (such as expiration) could also be useful to subvert additional user accounts.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_ensure_shadow_group_empty

References:

pcidss	Req-8.2.1
cis	6.2.4
pcidss4	8.3.2, 8.3

Remediation Shell script ⇲


sed -ri 's/(^shadow:[^:]*:[^:]*:)([^:]+$)/\1/' /etc/group

Group Set Password Expiration Parameters Group contains 5 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 365

A value of 180 days is sufficient for many environments. The DoD requirement is 60. The profile requirement is 365.

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
stigid	UBTU-22-411030
cis	5.5.1.2
pcidss4	8.3.9, 8.3
stigref	SV-260546r986281_rule

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'login' 2>/dev/null | grep -q installed; then

var_accounts_maximum_age_login_defs='365'

# 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

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 1

A value of 1 day is considered sufficient for many environments. The DoD requirement is 1. The profile requirement is 1.

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
stigid	UBTU-22-411025
cis	5.5.1.1
stigref	SV-260545r986280_rule

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'login' 2>/dev/null | grep -q installed; then

var_accounts_minimum_age_login_defs='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' <<< "^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

Rule Set Existing Passwords Maximum Age [ref]

Configure non-compliant accounts to enforce a 365-day maximum password lifetime restriction by running the following command:

$ sudo chage -M 365
          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
cis	5.5.1.2
pcidss4	8.3.9, 8.3

Remediation Shell script ⇲

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


var_accounts_maximum_age_login_defs='365'


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
cis	5.5.1.1

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 1
  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

Remediation Shell script ⇲

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


var_accounts_minimum_age_login_defs='1'


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)

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
cis	5.5.1.3
pcidss4	8.3.9, 8.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'login' 2>/dev/null | grep -q installed; 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

Group Verify Proper Storage and Existence of Password Hashes Group contains 6 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
cis	6.2.1
pcidss4	8.3.2, 8.3

Rule Ensure all users last password change date is in the past [ref]

All users should have a password change date in the past.

Warning: Automatic remediation is not available, in order to avoid any system disruption.

Rationale:

If a user recorded password change date is in the future then they could bypass any set password expiration.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_accounts_password_last_change_is_in_past

References:

cis	5.5.1.5
pcidss4	8.3.5, 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
cis	6.2.3
pcidss4	8.2.2, 8.2

Rule Ensure There Are No Accounts With Blank or Null Passwords [ref]

Check the "/etc/shadow" file for blank passwords with the following command:

$ sudo awk -F: '!$2 {print $1}' /etc/shadow

If the command returns any results, this is a finding. Configure all accounts on the system to have a password or lock the account with the following commands: Perform a password reset:

$ sudo passwd [username]

Lock an account:

$ sudo passwd -l [username]

Warning: 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_etc_shadow

References:

disa	CCI-000366
nist	CM-6(b), CM-6.1(iv)
os-srg	SRG-OS-000480-GPOS-00227
stigid	UBTU-22-611065
cis	6.2.2
pcidss4	2.2.2, 2.2
stigref	SV-260571r991589_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-611065
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.2
  - high_severity
  - low_complexity
  - low_disruption
  - no_empty_passwords_etc_shadow
  - no_reboot_needed
  - restrict_strategy

- name: Collect users with no password
  command: |
    awk -F: '!$2 {print $1}' /etc/shadow
  register: users_nopasswd
  changed_when: false
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-611065
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.2
  - high_severity
  - low_complexity
  - low_disruption
  - no_empty_passwords_etc_shadow
  - no_reboot_needed
  - restrict_strategy

- name: Lock users with no password
  command: |
    passwd -l {{ item }}
  with_items: '{{ users_nopasswd.stdout_lines }}'
  when:
  - '"linux-base" in ansible_facts.packages'
  - users_nopasswd is not skipped and users_nopasswd.stdout_lines | length > 0
  tags:
  - DISA-STIG-UBTU-22-611065
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.2
  - high_severity
  - low_complexity
  - low_disruption
  - no_empty_passwords_etc_shadow
  - no_reboot_needed
  - restrict_strategy

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

readarray -t users_with_empty_pass < <(sudo awk -F: '!$2 {print $1}' /etc/shadow)

for user_with_empty_pass in "${users_with_empty_pass[@]}"
do
    passwd -l $user_with_empty_pass
done

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

Rule Verify No .forward Files Exist [ref]

The .forward file specifies an email address to forward the user's mail to.

Rationale:

Use of the .forward file poses a security risk in that sensitive data may be inadvertently transferred outside the organization. The .forward file also poses a risk as it can be used to execute commands that may perform unintended actions.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_no_forward_files

References:

cis	6.2.15

Rule Verify No netrc Files Exist [ref]

The .netrc files contain login information used to auto-login into FTP servers and reside in the user's home directory. These files may contain unencrypted passwords to remote FTP servers making them susceptible to access by unauthorized users and should not be used. Any .netrc files should be removed.

Rationale:

Unencrypted passwords for remote FTP servers may be stored in .netrc files.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_no_netrc_files

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
disa	CCI-000196
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
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(h), IA-5(1)(c), CM-6(a), IA-5(7)
nist-csf	PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3
cis	6.2.14

Group Restrict Root Logins Group contains 6 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
cis	6.2.10
pcidss4	8.2.1, 8.2

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

Remediation Shell script ⇲

awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs --no-run-if-empty --max-lines=1 passwd -l

Rule Verify Root Has A Primary GID 0 [ref]

The root user should have a primary group of 0.

Rationale:

To help ensure that root-owned files are not inadvertently exposed to other users.

Severity:

high

Rule ID: xccdf_org.ssgproject.content_rule_accounts_root_gid_zero

References:

pcidss	Req-8.1.1
cis	5.5.3
pcidss4	8.2.1, 8.2

Rule Ensure the Group Used by pam_wheel.so Module Exists on System and is Empty [ref]

Ensure that the group sugroup referenced by var_pam_wheel_group_for_su variable and used as value for the pam_wheel.so group option exists and has no members. This empty group used by pam_wheel.so in /etc/pam.d/su ensures that no user can run commands with altered privileges through the su command.

Warning: Note that this rule just ensures the group exists and has no members. This rule does not configure pam_wheel.so module. The pam_wheel.so module configuration is accomplished by use_pam_wheel_group_for_su rule.

Rationale:

The su program allows to run commands with a substitute user and group ID. It is commonly used to run commands as the root user. Limiting access to such command is considered a good security practice.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_ensure_pam_wheel_group_empty

References:

cis	5.3.7
pcidss4	2.2.6, 2.2

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - ensure_pam_wheel_group_empty
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
- name: XCCDF Value var_pam_wheel_group_for_su # promote to variable
  set_fact:
    var_pam_wheel_group_for_su: !!str sugroup
  tags:
    - always

- name: Ensure the Group Used by pam_wheel.so Module Exists on System and is Empty
    - Ensure {{ var_pam_wheel_group_for_su }} Group Exists
  ansible.builtin.group:
    name: '{{ var_pam_wheel_group_for_su }}'
    state: present
  when: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - ensure_pam_wheel_group_empty
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure the Group Used by pam_wheel.so Module Exists on System and is Empty
    - Ensure {{ var_pam_wheel_group_for_su }} Group is Empty
  ansible.builtin.lineinfile:
    path: /etc/group
    regexp: ^({{ var_pam_wheel_group_for_su }}:[^:]+:[0-9]+:).*$
    line: \1
    backrefs: true
  when: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - ensure_pam_wheel_group_empty
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; then

var_pam_wheel_group_for_su='sugroup'


if ! grep -q "^${var_pam_wheel_group_for_su}:[^:]*:[^:]*:[^:]*" /etc/group; then
    groupadd ${var_pam_wheel_group_for_su}
fi

# group must be empty
gpasswd -M '' ${var_pam_wheel_group_for_su}

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

Rule Ensure Authentication Required for Single User Mode [ref]

Single user mode is used for recovery when the system detects an issue during boot or by manual selection from the bootloader.

Rationale:

Requiring authentication in single user mode prevents an unauthorized user from rebooting the system into single user to gain root privileges without credentials.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_ensure_root_password_configured

References:

cis	1.4.3
pcidss4	2.2.2, 2.2

Rule Ensure that System Accounts Do Not Run a Shell Upon Login [ref]

Some accounts are not associated with a human user of the system, and exist to perform some administrative functions. Should an attacker be able to log into these accounts, they should not be granted access to a shell.

The login shell for each local account is stored in the last field of each line in /etc/passwd. System accounts are those user accounts with a user ID less than 1000. The user ID is stored in the third field. If any system account other than root has a login shell, disable it with the command:

$ sudo usermod -s /sbin/nologin account

Warning: Do not perform the steps in this section on the root account. Doing so might cause the system to become inaccessible.

Rationale:

Ensuring shells are not given to system accounts upon login makes it more difficult for attackers to make use of system accounts.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_no_shelllogin_for_systemaccounts

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-000366
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
ism	1491
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-6, CM-6(a), CM-6(b), CM-6.1(iv)
nist-csf	DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6
os-srg	SRG-OS-000480-GPOS-00227
cis	5.5.2
pcidss4	8.2.2, 8.2

Remediation Ansible snippet ⇲

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

- name: Ensure that System Accounts Do Not Run a Shell Upon Login - Get All Local
    Users From /etc/passwd
  ansible.builtin.getent:
    database: passwd
    split: ':'
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - PCI-DSSv4-8.2
  - PCI-DSSv4-8.2.2
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - no_shelllogin_for_systemaccounts
  - restrict_strategy

- name: Ensure that System Accounts Do Not Run a Shell Upon Login - Create local_users
    Variable From getent_passwd Facts
  ansible.builtin.set_fact:
    local_users: '{{ ansible_facts.getent_passwd | dict2items }}'
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - PCI-DSSv4-8.2
  - PCI-DSSv4-8.2.2
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - no_shelllogin_for_systemaccounts
  - restrict_strategy

- name: Ensure that System Accounts Do Not Run a Shell Upon Login -  Disable Login
    Shell for System Accounts
  ansible.builtin.user:
    name: '{{ item.key }}'
    shell: /sbin/nologin
  loop: '{{ local_users }}'
  when:
  - item.key not in ['root']
  - item.value[1]|int < 1000
  - item.value[5] not in ['/sbin/shutdown', '/sbin/halt', '/bin/sync']
  tags:
  - NIST-800-53-AC-6
  - NIST-800-53-CM-6(a)
  - NIST-800-53-CM-6(b)
  - NIST-800-53-CM-6.1(iv)
  - PCI-DSSv4-8.2
  - PCI-DSSv4-8.2.2
  - low_complexity
  - medium_disruption
  - medium_severity
  - no_reboot_needed
  - no_shelllogin_for_systemaccounts
  - restrict_strategy

Remediation Shell script ⇲

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


readarray -t systemaccounts < <(awk -F: '($3 < 1000 && $3 != root \
  && $7 != "\/sbin\/shutdown" && $7 != "\/sbin\/halt" && $7 != "\/bin\/sync") \
  { print $1 }' /etc/passwd)

for systemaccount in "${systemaccounts[@]}"; do
    usermod -s /sbin/nologin "$systemaccount"
done

Rule Enforce Usage of pam_wheel with Group Parameter for su Authentication [ref]

To ensure that only users who are members of the group set in the group option of pam_wheel.so module can run commands with altered privileges through the su command, make sure that the following line exists in the file /etc/pam.d/su:

auth required pam_wheel.so use_uid group=sugroup

Warning: Note that ensure_pam_wheel_group_empty rule complements this requirement by ensuring the referenced group exists and has no members.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_use_pam_wheel_group_for_su

References:

cis	5.3.7
pcidss4	2.2.6, 2.2

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - use_pam_wheel_group_for_su
- name: XCCDF Value var_pam_wheel_group_for_su # promote to variable
  set_fact:
    var_pam_wheel_group_for_su: !!str sugroup
  tags:
    - always

- name: Enforce Usage of pam_wheel with Group Parameter for su Authentication - Add
    the group to the /etc/pam.d/su file
  ansible.builtin.lineinfile:
    path: /etc/pam.d/su
    state: present
    regexp: ^[\s]*#[\s]*auth[\s]+required[\s]+pam_wheel\.so[\s]+use_uid group=$
    line: auth             required        pam_wheel.so use_uid group={{ var_pam_wheel_group_for_su
      }}
  when: '"libpam-runtime" in ansible_facts.packages'
  tags:
  - PCI-DSSv4-2.2
  - PCI-DSSv4-2.2.6
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy
  - use_pam_wheel_group_for_su

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'libpam-runtime' 2>/dev/null | grep -q installed; then

var_pam_wheel_group_for_su='sugroup'


PAM_CONF=/etc/pam.d/su

pamstr=$(grep -P '^auth\s+required\s+pam_wheel\.so\s+(?=[^#]*\buse_uid\b)(?=[^#]*\bgroup=)' ${PAM_CONF})
if [ -z "$pamstr" ]; then
    sed -Ei '/^auth\b.*\brequired\b.*\bpam_wheel\.so/d' ${PAM_CONF} # remove any remaining uncommented pam_wheel.so line
    sed -Ei "/^auth\s+sufficient\s+pam_rootok\.so.*$/a auth             required        pam_wheel.so use_uid group=${var_pam_wheel_group_for_su}" ${PAM_CONF}
else
    group_val=$(echo -n "$pamstr" | grep -Eo '\bgroup=[_a-z][-0-9_a-z]*' | cut -d '=' -f 2)
    if [ -z "${group_val}" ] || [ ${group_val} != ${var_pam_wheel_group_for_su} ]; then
        sed -Ei "s/(^auth\s+required\s+pam_wheel.so\s+[^#]*group=)[_a-z][-0-9_a-z]*/\1${var_pam_wheel_group_for_su}/" ${PAM_CONF}
    fi
fi

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

Rule Ensure All Accounts on the System Have Unique User IDs [ref]

Change user IDs (UIDs), or delete accounts, so each has a unique name.

Warning: Automatic remediation of this control is not available due to unique requirements of each system.

Rationale:

To assure accountability and prevent unauthenticated access, interactive users must be identified and authenticated to prevent potential misuse and compromise of the system.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_account_unique_id

References:

disa	CCI-000135, CCI-000764, CCI-000804
pcidss	Req-8.1.1
os-srg	SRG-OS-000104-GPOS-00051, SRG-OS-000121-GPOS-00062
cis	6.2.5
pcidss4	8.2.1, 8.2

Rule Ensure All Groups on the System Have Unique Group ID [ref]

Change the group name or delete groups, so each has a unique id.

Warning: Automatic remediation of this control is not available due to the unique requirements of each system.

Rationale:

To assure accountability and prevent unauthenticated access, groups must be identified uniquely to prevent potential misuse and compromise of the system.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_group_unique_id

References:

disa	CCI-000764
os-srg	SRG-OS-000104-GPOS-00051
cis	6.2.6
pcidss4	8.2.1, 8.2

Rule Ensure All Groups on the System Have Unique Group Names [ref]

Change the group name or delete groups, so each has a unique name.

Warning: Automatic remediation of this control is not available due to the unique requirements of each system.

Rationale:

To assure accountability and prevent unauthenticated access, groups must be identified uniquely to prevent potential misuse and compromise of the system.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_group_unique_name

References:

cis	6.2.8
pcidss4	8.2.1, 8.2

Group Secure Session Configuration Files for Login Accounts Group contains 2 groups and 14 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 No Dangerous Directories Exist in Root's Path Group contains 2 rules

[ref] The active path of the root account can be obtained by starting a new root shell and running:

# echo $PATH

This will produce a colon-separated list of directories in the path.

Certain path elements could be considered dangerous, as they could lead to root executing unknown or untrusted programs, which could contain malicious code. Since root may sometimes work inside untrusted directories, the . character, which represents the current directory, should never be in the root path, nor should any directory which can be written to by an unprivileged or semi-privileged (system) user.

It is a good practice for administrators to always execute privileged commands by typing the full path to the command.

Rule Ensure that Root's Path Does Not Include World or Group-Writable Directories [ref]

For each element in root's path, run:

# ls -ld DIR

and ensure that write permissions are disabled for group and other.

Rationale:

Such entries increase the risk that root could execute code provided by unprivileged users, and potentially malicious code.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_accounts_root_path_dirs_no_write

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	CM-6(a), CM-6(a)
nist-csf	PR.IP-1
cis	6.2.9

Rule Ensure that Root's Path Does Not Include Relative Paths or Null Directories [ref]

Ensure that none of the directories in root's path is equal to a single . character, or that it contains any instances that lead to relative path traversal, such as .. or beginning a path without the slash (/) character. Also ensure that there are no "empty" elements in the path, such as in these examples:

PATH=:/bin
PATH=/bin:
PATH=/bin::/sbin

These empty elements have the same effect as a single . character.

Rationale:

Including these entries increases the risk that root could execute code from an untrusted location.

Severity:

unknown

Rule ID: xccdf_org.ssgproject.content_rule_root_path_no_dot

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	CM-6(a), CM-6(a)
nist-csf	PR.IP-1
cis	6.2.9

Group Ensure that Users Have Sensible Umask Values Group contains 4 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 Bash Umask is Set Correctly [ref]

To ensure the default umask for users of the Bash shell is set properly, add or correct the umask setting in /etc/bash.bashrc to read as follows:

umask 027

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 or written to by unauthorized users.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_umask_etc_bashrc

References:

cis-csc	18
cobit5	APO13.01, BAI03.01, BAI03.02, BAI03.03
disa	CCI-000366
isa-62443-2009	4.3.4.3.3
iso27001-2013	A.14.1.1, A.14.2.1, 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-2
os-srg	SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227
cis	5.5.4
anssi	R36

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_bashrc
  - 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 027
  tags:
    - always

- name: Check if umask in /etc/bash.bashrc is already set
  ansible.builtin.lineinfile:
    path: /etc/bash.bashrc
    regexp: ^[^#]*\bumask\s+\d+$
    state: absent
  check_mode: true
  changed_when: false
  register: umask_replace
  when: '"bash" in ansible_facts.packages'
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_bashrc
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Replace user umask in /etc/bash.bashrc
  ansible.builtin.replace:
    path: /etc/bash.bashrc
    regexp: ^([^#]*\b)umask\s+\d+$
    replace: \g<1>umask {{ var_accounts_user_umask }}
  when:
  - '"bash" in ansible_facts.packages'
  - umask_replace.found > 0
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_bashrc
  - 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/bash.bashrc
    line: umask {{ var_accounts_user_umask }}
  when:
  - '"bash" in ansible_facts.packages'
  - umask_replace.found == 0
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_bashrc
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'bash' 2>/dev/null | grep -q installed; then

var_accounts_user_umask='027'






grep -q "^[^#]*\bumask" /etc/bash.bashrc && \
  sed -i -E -e "s/^([^#]*\bumask)[[:space:]]+[[:digit:]]+/\1 $var_accounts_user_umask/g" /etc/bash.bashrc
if ! [ $? -eq 0 ]; then
    echo "umask $var_accounts_user_umask" >> /etc/bash.bashrc
fi

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

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 027

Rationale:

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
stigid	UBTU-22-412035
cis	5.5.4
anssi	R36
stigref	SV-260555r991590_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-412035
  - 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 027
  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: '"login" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-412035
  - 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:
  - '"login" in ansible_facts.packages'
  - result_umask_is_set.found > 0
  tags:
  - DISA-STIG-UBTU-22-412035
  - 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:
  - '"login" in ansible_facts.packages'
  - result_umask_is_set.found == 0
  tags:
  - DISA-STIG-UBTU-22-412035
  - 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

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'login' 2>/dev/null | grep -q installed; then

var_accounts_user_umask='027'


# 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

Rule Ensure the Default Umask is Set Correctly in /etc/profile [ref]

To ensure the default umask controlled by /etc/profile is set properly, add or correct the umask setting in /etc/profile to read as follows:

umask 027

Note that /etc/profile also reads scrips within /etc/profile.d directory. These scripts are also valid files to set umask value. Therefore, they should also be considered during the check and properly remediated, if necessary.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_accounts_umask_etc_profile

References:

cis-csc	18
cobit5	APO13.01, BAI03.01, BAI03.02, BAI03.03
disa	CCI-000366
isa-62443-2009	4.3.4.3.3
iso27001-2013	A.14.1.1, A.14.2.1, 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-2
os-srg	SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227
cis	5.5.4
anssi	R36

Remediation Ansible snippet ⇲

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

- name: XCCDF Value var_accounts_user_umask # promote to variable
  set_fact:
    var_accounts_user_umask: !!str 027
  tags:
    - always

- name: Ensure the Default Umask is Set Correctly in /etc/profile - Locate Profile
    Configuration Files Where umask Is Defined
  ansible.builtin.find:
    paths:
    - /etc/profile.d
    patterns:
    - sh.local
    - '*.sh'
    contains: ^[\s]*umask\s+\d+
  register: result_profile_d_files
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_profile
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure the Default Umask is Set Correctly in /etc/profile - Replace Existing
    umask Value in Files From /etc/profile.d
  ansible.builtin.replace:
    path: '{{ item.path }}'
    regexp: ^(\s*)umask\s+\d+
    replace: \1umask {{ var_accounts_user_umask }}
  loop: '{{ result_profile_d_files.files }}'
  register: result_umask_replaced_profile_d
  when: result_profile_d_files.matched
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_profile
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure the Default Umask is Set Correctly in /etc/profile - Ensure umask Is
    Set in /etc/profile if Not Already Set Elsewhere
  ansible.builtin.lineinfile:
    create: true
    mode: 420
    path: /etc/profile
    line: umask {{ var_accounts_user_umask }}
  when: not result_profile_d_files.matched
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_profile
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Ensure the Default Umask is Set Correctly in /etc/profile - Ensure umask Value
    For All Existing umask Definition in /etc/profile
  ansible.builtin.replace:
    path: /etc/profile
    regexp: ^(\s*)umask\s+\d+
    replace: \1umask {{ var_accounts_user_umask }}
  register: result_umask_replaced_profile
  tags:
  - NIST-800-53-AC-6(1)
  - NIST-800-53-CM-6(a)
  - accounts_umask_etc_profile
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Remediation Shell script ⇲

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


var_accounts_user_umask='027'


readarray -t profile_files < <(find /etc/profile.d/ -type f -name '*.sh' -or -name 'sh.local')

for file in "${profile_files[@]}" /etc/profile; do
  grep -qE '^[^#]*umask' "$file" && sed -i -E "s/^(\s*umask\s*)[0-7]+/\1$var_accounts_user_umask/g" "$file"
done

if ! grep -qrE '^[^#]*umask' /etc/profile*; then
  echo "umask $var_accounts_user_umask" >> /etc/profile
fi

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
cis	5.5.4

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:

TMOUT=900

readonly TMOUT export TMOUT

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
stigid	UBTU-22-412030
cis	5.5.5
anssi	R32
pcidss4	8.6.1, 8.6
stigref	SV-260554r958636_rule

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-412030
  - 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 900
  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: '"linux-base" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-412030
  - 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: '"linux-base" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-412030
  - 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

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

var_accounts_tmout='900'


# if 0, no occurence of tmout found, if 1, occurence found
tmout_found=0

for f in /etc/bash.bashrc /etc/profile /etc/profile.d/*.sh; do
    if grep --silent '^\s*TMOUT' $f; then
        sed -i -E "s/^(\s*)TMOUT\s*=\s*(\w|\$)*(.*)$/\1TMOUT=$var_accounts_tmout\3/g" $f
        tmout_found=1
        if ! grep --silent '^\s*readonly TMOUT' $f ; then
            echo "readonly TMOUT" >> $f
        fi
        if ! grep --silent '^\s*export TMOUT' $f ; then
            echo "export TMOUT" >> $f
        fi
    fi
done

if [ $tmout_found -eq 0 ]; then
        echo -e "\n# Set TMOUT to $var_accounts_tmout per security requirements" >> /etc/profile.d/tmout.sh
        echo "TMOUT=$var_accounts_tmout" >> /etc/profile.d/tmout.sh
        echo "readonly TMOUT" >> /etc/profile.d/tmout.sh
        echo "export TMOUT" >> /etc/profile.d/tmout.sh
fi

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

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
cis	6.2.17
anssi	R50

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

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

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
cis	6.2.17

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

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

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
cis	6.2.17
anssi	R50

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

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

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
cis	6.2.11

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

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

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
cis	6.2.12

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

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

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
cis	6.2.12

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

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

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
cis	6.2.13

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

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

Group AppArmor Group contains 3 rules

[ref] Many security vulnerabilities result from bugs in trusted programs. A trusted program runs with privileges that attackers want to possess. The program fails to keep that trust if there is a bug in the program that allows the attacker to acquire said privilege.

AppArmor® is an application security solution designed specifically to apply privilege confinement to suspect programs. AppArmor allows the administrator to specify the domain of activities the program can perform by developing a security profile. A security profile is a listing of files that the program may access and the operations the program may perform. AppArmor secures applications by enforcing good application behavior without relying on attack signatures, so it can prevent attacks even if previously unknown vulnerabilities are being exploited.

Rule Ensure AppArmor is installed [ref]

AppArmor provide Mandatory Access Controls.

Rationale:

Without a Mandatory Access Control system installed only the default Discretionary Access Control system will be available.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_apparmor_installed

References:

disa	CCI-001764, CCI-001774, CCI-002165, CCI-002235
os-srg	SRG-OS-000368-GPOS-00154, SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000312-GPOS-00124, SRG-OS-000324-GPOS-00125, SRG-OS-000370-GPOS-00155
stigid	UBTU-22-431010
cis	1.6.1.1
anssi	R45
stigref	SV-260556r958702_rule

Remediation Puppet snippet ⇲

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

include install_apparmor

class install_apparmor {
  package { 'apparmor':
    ensure => 'installed',
  }
}

Remediation Ansible snippet ⇲

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

- name: Ensure apparmor is installed
  package:
    name: apparmor
    state: present
  when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  tags:
  - DISA-STIG-UBTU-22-431010
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_apparmor_installed

Remediation OSBuild Blueprint snippet ⇲


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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

DEBIAN_FRONTEND=noninteractive apt-get install -y "apparmor"

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

Rule All AppArmor Profiles are in enforce or complain mode [ref]

AppArmor profiles define what resources applications are able to access. To set all profiles to either enforce or complain mode run the following command to set all profiles to enforce mode:

$ sudo aa-enforce /etc/apparmor.d/*

run the following command to set all profiles to complain mode:

$ sudo aa-complain /etc/apparmor.d/*

To list unconfined processes run the following command:

$ sudo apparmor_status | grep processes

Any unconfined processes may need to have a profile created or activated for them and then be restarted.

Rationale:

Security configuration requirements vary from site to site. Some sites may mandate a policy that is stricter than the default policy, which is perfectly acceptable. This recommendation is intended to ensure that any policies that exist on the system are activated.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_all_apparmor_profiles_in_enforce_complain_mode

References:

cis	1.6.1.3

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && dpkg-query --show --showformat='${db:Status-Status}\n' 'apparmor' 2>/dev/null | grep -q installed ); }; then

var_apparmor_mode='enforce'


# make sure apparmor-utils is installed for aa-complain and aa-enforce
DEBIAN_FRONTEND=noninteractive apt-get install -y "apparmor-utils"

# Reload all AppArmor profiles
apparmor_parser -q -r /etc/apparmor.d/

# Set the mode
APPARMOR_MODE="$var_apparmor_mode"

if [ "$APPARMOR_MODE" = "enforce" ]
then
  
  # Set all profiles to enforce mode except disabled profiles
  find /etc/apparmor.d -maxdepth 1 ! -type d -exec bash -c '[[ -e "/etc/apparmor.d/disable/$(basename "$1")" ]] || aa-enforce "$1"' _ {} \;
  
fi

if [ "$APPARMOR_MODE" = "complain" ]
then
  
  # Load all not-loaded profiles into complain mode
  apparmor_parser -a --Complain /etc/apparmor.d/
  echo "***WARNING***: This remediation will not downgrade any existing AppArmor profiles."
  
fi


UNCONFINED=$(aa-status | grep "processes are unconfined" | awk '{print $1;}')
if [ $UNCONFINED -ne 0 ];

then
  echo -e "***WARNING***: There are some unconfined processes:"
  echo -e "----------------------------"
  echo "The may need to have a profile created or activated for them and then be restarted."
  for PROCESS in "${UNCONFINED[@]}"
  do
      echo "$PROCESS"
  done
  echo -e "----------------------------"
  echo "The may need to have a profile created or activated for them and then be restarted."
fi

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

Rule Ensure AppArmor is enabled in the bootloader configuration [ref]

Configure AppArmor to be enabled at boot time and verify that it has not been overwritten by the bootloader boot parameters. Note: This recommendation is designed around the grub bootloader, if LILO or another bootloader is in use in your environment, enact equivalent settings.

Rationale:

AppArmor must be enabled at boot time in your bootloader configuration to ensure that the controls it provides are not overridden.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_grub2_enable_apparmor

References:

cis	1.6.1.2
anssi	R45

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

# Correct the form of default kernel command line in GRUB
if grep -q '^\s*GRUB_CMDLINE_LINUX=.*apparmor=.*"'  '/etc/default/grub' ; then
       # modify the GRUB command-line if an apparmor= arg already exists
       sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)apparmor=[^[:space:]]\+\(.*\"\)/\1apparmor=1\2/"  '/etc/default/grub'
# Add to already existing GRUB_CMDLINE_LINUX parameters
elif grep -q '^\s*GRUB_CMDLINE_LINUX='  '/etc/default/grub' ; then
       # no apparmor=arg is present, append it
       sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)\"/\1 apparmor=1\"/"  '/etc/default/grub'
# Add GRUB_CMDLINE_LINUX parameters line
else
       echo "GRUB_CMDLINE_LINUX=\"apparmor=1\"" >> '/etc/default/grub'
fi
# Correct the form of default kernel command line in GRUB
if grep -q '^\s*GRUB_CMDLINE_LINUX=.*security=.*"'  '/etc/default/grub' ; then
       # modify the GRUB command-line if an security= arg already exists
       sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)security=[^[:space:]]\+\(.*\"\)/\1security=apparmor\2/"  '/etc/default/grub'
# Add to already existing GRUB_CMDLINE_LINUX parameters
elif grep -q '^\s*GRUB_CMDLINE_LINUX='  '/etc/default/grub' ; then
       # no security=arg is present, append it
       sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)\"/\1 security=apparmor\"/"  '/etc/default/grub'
# Add GRUB_CMDLINE_LINUX parameters line
else
       echo "GRUB_CMDLINE_LINUX=\"security=apparmor\"" >> '/etc/default/grub'
fi


update-grub

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

Group GRUB2 bootloader configuration Group contains 2 groups and 4 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 Ubuntu 22.04 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 3 rules

[ref] Non-UEFI GRUB2 bootloader configuration

Rule Verify /boot/grub/grub.cfg User Ownership [ref]

The file /boot/grub/grub.cfg should be owned by the root user to prevent destruction or modification of the file. To properly set the owner of /boot/grub/grub.cfg, run the command:

$ sudo chown root /boot/grub/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
cis	1.4.2
anssi	R29
pcidss4	2.2.6, 2.2

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/grub/grub.cfg
  stat:
    path: /boot/grub/grub.cfg
  register: file_exists
  when:
  - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
  - '"grub2-common" in ansible_facts.packages'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  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/grub/grub.cfg
  file:
    path: /boot/grub/grub.cfg
    owner: '0'
  when:
  - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
  - '"grub2-common" in ansible_facts.packages'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  - 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if [ ! -d /sys/firmware/efi ] && dpkg-query --show --showformat='${db:Status-Status}\n' 'grub2-common' 2>/dev/null | grep -q installed && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

chown 0 /boot/grub/grub.cfg

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

Rule Verify /boot/grub/grub.cfg Permissions [ref]

File permissions for /boot/grub/grub.cfg should be set to 600. To properly set the permissions of /boot/grub/grub.cfg, run the command:

$ sudo chmod 600 /boot/grub/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
cis	1.4.2
anssi	R29
pcidss4	2.2.6, 2.2

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/grub/grub.cfg
  stat:
    path: /boot/grub/grub.cfg
  register: file_exists
  when:
  - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
  - '"grub2-common" in ansible_facts.packages'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  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/grub/grub.cfg
  file:
    path: /boot/grub/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'
  - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
  - 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if [ ! -d /sys/firmware/efi ] && dpkg-query --show --showformat='${db:Status-Status}\n' 'grub2-common' 2>/dev/null | grep -q installed && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

chmod u-xs,g-xwrs,o-xwrt /boot/grub/grub.cfg

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

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-mkpasswd-pbkdf2

When prompted, enter the password that was selected.

Using the hash from the output, modify the /etc/grub.d/40_custom file with the following content:

set superusers="boot"
password_pbkdf2 boot grub.pbkdf2.sha512.VeryLongString

NOTE: the bootloader superuser account and password MUST differ from the root account and password. Once the superuser password has been added, update the grub.cfg file by running:

update-grub

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
stigid	UBTU-22-212010
cis	1.4.1
anssi	R5
stigref	SV-260470r958472_rule

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-mkpasswd-pbkdf2

When prompted, enter the password that was selected.

Using the hash from the output, modify the /etc/grub.d/40_custom file with the following content:

set superusers="boot"
password_pbkdf2 boot grub.pbkdf2.sha512.VeryLongString

NOTE: the bootloader superuser account and password MUST differ from the root account and password. Once the superuser password has been added, update the grub.cfg file by running:

update-grub

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
stigid	UBTU-22-212010
cis	1.4.1
anssi	R5
stigref	SV-260470r958472_rule

Group Configure Syslog Group contains 3 groups and 10 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 Ubuntu 22.04, 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 systemd-journald Group contains 5 rules

[ref] systemd-journald is a system service that collects and stores logging data. It creates and maintains structured, indexed journals based on logging information that is received from a variety of sources. For more information on systemd-journald and additional systemd-journald configuration options, see https://systemd.io/.

Rule Install systemd-journal-remote Package [ref]

Journald (via systemd-journal-remote ) supports the ability to send log events it gathers to a remote log host or to receive messages from remote hosts, thus enabling centralised log management.

Rationale:

Storing log data on a remote host protects log integrity from local attacks. If an attacker gains root access on the local system, they could tamper with or remove log data that is stored on the local system.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_systemd-journal-remote_installed

References:

os-srg	SRG-OS-000479-GPOS-00224
cis	4.2.1.1.1

Remediation Puppet snippet ⇲

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

include install_systemd-journal-remote

class install_systemd-journal-remote {
  package { 'systemd-journal-remote':
    ensure => 'installed',
  }
}

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
  - package_systemd-journal-remote_installed

- name: Ensure systemd-journal-remote is installed
  package:
    name: systemd-journal-remote
    state: present
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_systemd-journal-remote_installed

Remediation OSBuild Blueprint snippet ⇲


[[packages]]
name = "systemd-journal-remote"
version = "*"

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

DEBIAN_FRONTEND=noninteractive apt-get install -y "systemd-journal-remote"

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

Rule Enable systemd-journald Service [ref]

The systemd-journald service is an essential component of systemd. The systemd-journald service can be enabled with the following command:

$ sudo systemctl enable systemd-journald.service

Rationale:

In the event of a system failure, Ubuntu 22.04 must preserve any information necessary to determine cause of failure and any information necessary to return to operations with least disruption to system processes.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_systemd-journald_enabled

References:

disa	CCI-001665
nist	SC-24
os-srg	SRG-OS-000269-GPOS-00103
cis	4.2.1.2

Remediation Puppet snippet ⇲

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

include enable_systemd-journald

class enable_systemd-journald {
  service {'systemd-journald':
    enable => true,
    ensure => 'running',
  }
}

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - NIST-800-53-SC-24
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_systemd-journald_enabled

- name: Enable systemd-journald Service - Enable service systemd-journald
  block:

  - name: Gather the package facts
    package_facts:
      manager: auto

  - name: Enable systemd-journald Service - Enable Service systemd-journald
    ansible.builtin.systemd:
      name: systemd-journald
      enabled: true
      state: started
      masked: false
    when:
    - '"systemd" in ansible_facts.packages'
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - NIST-800-53-SC-24
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_systemd-journald_enabled

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
enabled = ["systemd-journald"]

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'systemd-journald.service'
"$SYSTEMCTL_EXEC" start 'systemd-journald.service'
"$SYSTEMCTL_EXEC" enable 'systemd-journald.service'

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

Rule Ensure journald is configured to compress large log files [ref]

The journald system can compress large log files to avoid fill the system disk.

Rationale:

Log files that are not properly compressed run the risk of growing so large that they fill up the log partition. Valuable logging information could be lost if the log partition becomes full.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_journald_compress

References:

cis	4.2.1.3

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - journald_compress
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Setting unquoted shell-style assignment of 'Compress' to 'yes' in '/etc/systemd/journald.conf'
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/systemd/journald.conf
      create: true
      regexp: (?i)^\s*Compress=
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/systemd/journald.conf
    lineinfile:
      path: /etc/systemd/journald.conf
      create: true
      regexp: (?i)^\s*Compress=
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/systemd/journald.conf
    lineinfile:
      path: /etc/systemd/journald.conf
      create: true
      regexp: (?i)^\s*Compress=
      line: Compress=yes
      state: present
      insertbefore: ^# Compress
      validate: /usr/bin/bash -n %s
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - journald_compress
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

if [ -e "/etc/systemd/journald.conf" ] ; then
    
    LC_ALL=C sed -i "/^\s*Compress\s*=\s*/d" "/etc/systemd/journald.conf"
else
    touch "/etc/systemd/journald.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/systemd/journald.conf"

cp "/etc/systemd/journald.conf" "/etc/systemd/journald.conf.bak"
# Insert before the line matching the regex '^#\s*Compress'.
line_number="$(LC_ALL=C grep -n "^#\s*Compress" "/etc/systemd/journald.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^#\s*Compress', insert at
    # the end of the file.
    printf '%s\n' "Compress=yes" >> "/etc/systemd/journald.conf"
else
    head -n "$(( line_number - 1 ))" "/etc/systemd/journald.conf.bak" > "/etc/systemd/journald.conf"
    printf '%s\n' "Compress=yes" >> "/etc/systemd/journald.conf"
    tail -n "+$(( line_number ))" "/etc/systemd/journald.conf.bak" >> "/etc/systemd/journald.conf"
fi
# Clean up after ourselves.
rm "/etc/systemd/journald.conf.bak"

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

Rule Ensure journald is configured to write log files to persistent disk [ref]

The journald system may store log files in volatile memory or locally on disk. If the logs are only stored in volatile memory they will we lost upon reboot.

Rationale:

Log files contain valuable data and need to be persistent to aid in possible investigations.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_journald_storage

References:

cis	4.2.1.4

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - journald_storage
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

- name: Setting unquoted shell-style assignment of 'Storage' to 'persistent' in '/etc/systemd/journald.conf'
  block:

  - name: Check for duplicate values
    lineinfile:
      path: /etc/systemd/journald.conf
      create: true
      regexp: (?i)^\s*Storage=
      state: absent
    check_mode: true
    changed_when: false
    register: dupes

  - name: Deduplicate values from /etc/systemd/journald.conf
    lineinfile:
      path: /etc/systemd/journald.conf
      create: true
      regexp: (?i)^\s*Storage=
      state: absent
    when: dupes.found is defined and dupes.found > 1

  - name: Insert correct line to /etc/systemd/journald.conf
    lineinfile:
      path: /etc/systemd/journald.conf
      create: true
      regexp: (?i)^\s*Storage=
      line: Storage=persistent
      state: present
      insertbefore: ^# Storage
      validate: /usr/bin/bash -n %s
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - journald_storage
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - restrict_strategy

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

if [ -e "/etc/systemd/journald.conf" ] ; then
    
    LC_ALL=C sed -i "/^\s*Storage\s*=\s*/d" "/etc/systemd/journald.conf"
else
    touch "/etc/systemd/journald.conf"
fi
# make sure file has newline at the end
sed -i -e '$a\' "/etc/systemd/journald.conf"

cp "/etc/systemd/journald.conf" "/etc/systemd/journald.conf.bak"
# Insert before the line matching the regex '^#\s*Storage'.
line_number="$(LC_ALL=C grep -n "^#\s*Storage" "/etc/systemd/journald.conf.bak" | LC_ALL=C sed 's/:.*//g')"
if [ -z "$line_number" ]; then
    # There was no match of '^#\s*Storage', insert at
    # the end of the file.
    printf '%s\n' "Storage=persistent" >> "/etc/systemd/journald.conf"
else
    head -n "$(( line_number - 1 ))" "/etc/systemd/journald.conf.bak" > "/etc/systemd/journald.conf"
    printf '%s\n' "Storage=persistent" >> "/etc/systemd/journald.conf"
    tail -n "+$(( line_number ))" "/etc/systemd/journald.conf.bak" >> "/etc/systemd/journald.conf"
fi
# Clean up after ourselves.
rm "/etc/systemd/journald.conf.bak"

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

Rule Disable systemd-journal-remote Socket [ref]

Journald supports the ability to receive messages from remote hosts, thus acting as a log server. Clients should not receive data from other hosts. NOTE: The same package, systemd-journal-remote , is used for both sending logs to remote hosts and receiving incoming logs. With regards to receiving logs, there are two Systemd unit files; systemd-journal-remote.socket and systemd-journal-remote.service.

Rationale:

If a client is configured to also receive data, thus turning it into a server, the client system is acting outside it's operational boundary.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_socket_systemd-journal-remote_disabled

References:

cis	4.2.1.1.4

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - socket_systemd-journal-remote_disabled

- name: Disable systemd-journal-remote Socket - Collect systemd Socket Units Present
    in the System
  ansible.builtin.command:
    cmd: systemctl -q list-unit-files --type socket
  register: result_systemd_unit_files
  changed_when: false
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - socket_systemd-journal-remote_disabled

- name: Disable systemd-journal-remote Socket - Ensure systemd-journal-remote.socket
    is Masked
  ansible.builtin.systemd:
    name: systemd-journal-remote.socket
    state: stopped
    enabled: false
    masked: true
  when:
  - '"linux-base" in ansible_facts.packages'
  - result_systemd_unit_files.stdout_lines is search("systemd-journal-remote.socket")
  tags:
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - socket_systemd-journal-remote_disabled

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

SOCKET_NAME="systemd-journal-remote.socket"
SYSTEMCTL_EXEC='/usr/bin/systemctl'

if "$SYSTEMCTL_EXEC" -q list-unit-files --type socket | grep -q "$SOCKET_NAME"; then
    "$SYSTEMCTL_EXEC" stop "$SOCKET_NAME"
    "$SYSTEMCTL_EXEC" mask "$SOCKET_NAME"
fi

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

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
cis	4.2.2.7

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: '"linux-base" 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: '"linux-base" 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: '"linux-base" 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: '"linux-base" 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:
  - '"linux-base" 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: '"linux-base" 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: '"linux-base" 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: '"linux-base" 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: '"linux-base" 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:
  - '"linux-base" 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:
  - '"linux-base" 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; 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

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
cis	4.2.2.6
anssi	R71

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; 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

Rule Ensure rsyslog is Installed [ref]

Rsyslog is installed by default. The rsyslog package can be installed with the following command:

 $ apt-get install rsyslog

Rationale:

The rsyslog package provides the rsyslog daemon, which provides system logging services.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_rsyslog_installed

References:

cis-csc	1, 14, 15, 16, 3, 5, 6
cobit5	APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01
disa	CCI-000366, CCI-000154, CCI-001851
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
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)
nist-csf	PR.PT-1
os-srg	SRG-OS-000479-GPOS-00224, SRG-OS-000051-GPOS-00024, SRG-OS-000480-GPOS-00227
cis	4.2.2.1

Remediation Puppet snippet ⇲

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

include install_rsyslog

class install_rsyslog {
  package { 'rsyslog':
    ensure => 'installed',
  }
}

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_rsyslog_installed

- name: Ensure rsyslog is installed
  package:
    name: rsyslog
    state: present
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_rsyslog_installed

Remediation OSBuild Blueprint snippet ⇲


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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

DEBIAN_FRONTEND=noninteractive apt-get install -y "rsyslog"

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

Rule Enable rsyslog Service [ref]

The rsyslog service provides syslog-style logging by default on Ubuntu 22.04. The rsyslog service can be enabled with the following command:

$ sudo systemctl enable rsyslog.service

Rationale:

The rsyslog service must be running in order to provide logging services, which are essential to system administration.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_service_rsyslog_enabled

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, APO13.01, BAI03.05, BAI04.04, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01
disa	CCI-000366
hipaa	164.312(a)(2)(ii)
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, 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.14.2.7, A.15.2.1, A.15.2.2, A.17.2.1
nist	CM-6(a), AU-4(1)
nist-csf	DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.DS-4, PR.PT-1
os-srg	SRG-OS-000480-GPOS-00227
stigid	UBTU-22-652010
cis	4.2.2.2
stigref	SV-260588r991562_rule

Remediation Puppet snippet ⇲

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

include enable_rsyslog

class enable_rsyslog {
  service {'rsyslog':
    enable => true,
    ensure => 'running',
  }
}

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - DISA-STIG-UBTU-22-652010
  - NIST-800-53-AU-4(1)
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_rsyslog_enabled

- name: Enable rsyslog Service - Enable service rsyslog
  block:

  - name: Gather the package facts
    package_facts:
      manager: auto

  - name: Enable rsyslog Service - Enable Service rsyslog
    ansible.builtin.systemd:
      name: rsyslog
      enabled: true
      state: started
      masked: false
    when:
    - '"rsyslog" in ansible_facts.packages'
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - DISA-STIG-UBTU-22-652010
  - NIST-800-53-AU-4(1)
  - NIST-800-53-CM-6(a)
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - service_rsyslog_enabled

Remediation OSBuild Blueprint snippet ⇲


[customizations.services]
enabled = ["rsyslog"]

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

SYSTEMCTL_EXEC='/usr/bin/systemctl'
"$SYSTEMCTL_EXEC" unmask 'rsyslog.service'
"$SYSTEMCTL_EXEC" start 'rsyslog.service'
"$SYSTEMCTL_EXEC" enable 'rsyslog.service'

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

Rule Ensure rsyslog Default File Permissions Configured [ref]

rsyslog will create logfiles that do not already exist on the system. This settings controls what permissions will be applied to these newly created files.

Rationale:

It is important to ensure that log files have the correct permissions to ensure that sensitive data is archived and protected.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_rsyslog_filecreatemode

References:

cis	4.2.2.4

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_filecreatemode

- name: Ensure rsyslog Default File Permissions Configured - Search for $FileCreateMode
    Parameter in rsyslog Main Config File
  ansible.builtin.find:
    paths: /etc
    pattern: rsyslog.conf
    contains: ^\s*\$FileCreateMode\s*\d+
  register: rsyslog_main_file_with_filecreatemode
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_filecreatemode

- name: Ensure rsyslog Default File Permissions Configured - Search for $FileCreateMode
    Parameter in rsyslog Include Files
  ansible.builtin.find:
    paths: /etc/rsyslog.d/
    pattern: '*.conf'
    contains: ^\s*\$FileCreateMode\s*\d+
  register: rsyslog_includes_with_filecreatemode
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_filecreatemode

- name: Ensure rsyslog Default File Permissions Configured - Assemble List of rsyslog
    Configuration Files with $FileCreateMode Parameter
  ansible.builtin.set_fact:
    rsyslog_filecreatemode_files: '{{ rsyslog_main_file_with_filecreatemode.files
      | map(attribute=''path'') | list + rsyslog_includes_with_filecreatemode.files
      | map(attribute=''path'') | list }}'
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_filecreatemode

- name: Ensure rsyslog Default File Permissions Configured - Remove $FileCreateMode
    Parameter from Multiple Files to Avoid Conflicts
  ansible.builtin.lineinfile:
    path: '{{ item }}'
    regexp: \$FileCreateMode.*
    state: absent
  register: result_rsyslog_filecreatemode_removed
  loop: '{{ rsyslog_filecreatemode_files }}'
  when:
  - '"linux-base" in ansible_facts.packages'
  - rsyslog_filecreatemode_files | length > 1
  tags:
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_filecreatemode

- name: Ensure rsyslog Default File Permissions Configured - Add $FileCreateMode Parameter
    and Expected Value
  ansible.builtin.lineinfile:
    path: /etc/rsyslog.d/99-rsyslog_filecreatemode.conf
    line: $FileCreateMode 0640
    mode: 416
    create: true
  when:
  - '"linux-base" in ansible_facts.packages'
  - rsyslog_filecreatemode_files | length == 0 or result_rsyslog_filecreatemode_removed
    is not skipped
  tags:
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_filecreatemode

- name: Ensure rsyslog Default File Permissions Configured - Ensure Correct Value
    of Existing $FileCreateMode Parameter
  ansible.builtin.lineinfile:
    path: '{{ item }}'
    regexp: ^\$FileCreateMode
    line: $FileCreateMode 0640
  loop: '{{ rsyslog_filecreatemode_files }}'
  when:
  - '"linux-base" in ansible_facts.packages'
  - rsyslog_filecreatemode_files | length == 1
  tags:
  - configure_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - rsyslog_filecreatemode

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; then

readarray -t targets < <(grep -H '^\s*$FileCreateMode' /etc/rsyslog.conf /etc/rsyslog.d/*)

# if $FileCreateMode set in multiple places
if [ ${#targets[@]} -gt 1 ]; then
    # delete all and create new entry with expected value
    sed -i '/^\s*$FileCreateMode/d' /etc/rsyslog.conf /etc/rsyslog.d/*
    echo '$FileCreateMode 0640' > /etc/rsyslog.d/99-rsyslog_filecreatemode.conf
# if $FileCreateMode set in only one place
elif [ "${#targets[@]}" -eq 1 ]; then
    filename=$(echo "${targets[0]}" | cut -d':' -f1)
    value=$(echo "${targets[0]}" | cut -d' ' -f2)
    #convert to decimal and bitwise or operation
    result=$((8#$value | 416))
    # if more permissive than expected, then set it to 0640
    if [ $result -ne 416 ]; then
        # if value is wrong remove it
        sed -i '/^\s*$FileCreateMode/d' $filename
        echo '$FileCreateMode 0640' > $filename
    fi
else
    echo '$FileCreateMode 0640' > /etc/rsyslog.d/99-rsyslog_filecreatemode.conf
fi

systemctl restart rsyslog.service

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

Group Network Configuration and Firewalls Group contains 12 groups and 44 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 iptables and ip6tables Group contains 2 groups and 8 rules

[ref] A host-based firewall called netfilter is included as part of the Linux kernel distributed with the system. It is activated by default. This firewall is controlled by the program iptables, and the entire capability is frequently referred to by this name. An analogous program called ip6tables handles filtering for IPv6.

Unlike TCP Wrappers, which depends on the network server program to support and respect the rules written, netfilter filtering occurs at the kernel level, before a program can even process the data from the network packet. As such, any program on the system is affected by the rules written.

This section provides basic information about strengthening the iptables and ip6tables configurations included with the system. For more complete information that may allow the construction of a sophisticated ruleset tailored to your environment, please consult the references at the end of this section.

Group Inspect and Activate Default Rules Group contains 3 rules

[ref] View the currently-enforced iptables rules by running the command:

$ sudo iptables -nL --line-numbers

The command is analogous for ip6tables.

If the firewall does not appear to be active (i.e., no rules appear), activate it and ensure that it starts at boot by issuing the following commands (and analogously for ip6tables):

$ sudo service iptables restart

The default iptables rules are:

Chain INPUT (policy ACCEPT)
num  target     prot opt source       destination
1    ACCEPT     all  --  0.0.0.0/0    0.0.0.0/0    state RELATED,ESTABLISHED 
2    ACCEPT     icmp --  0.0.0.0/0    0.0.0.0/0
3    ACCEPT     all  --  0.0.0.0/0    0.0.0.0/0
4    ACCEPT     tcp  --  0.0.0.0/0    0.0.0.0/0    state NEW tcp dpt:22 
5    REJECT     all  --  0.0.0.0/0    0.0.0.0/0    reject-with icmp-host-prohibited 

Chain FORWARD (policy ACCEPT)
num  target     prot opt source       destination
1    REJECT     all  --  0.0.0.0/0    0.0.0.0/0    reject-with icmp-host-prohibited 

Chain OUTPUT (policy ACCEPT)
num  target     prot opt source       destination

The ip6tables default rules are essentially the same.

Rule Set Default ip6tables Policy for Incoming Packets [ref]

To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following line in /etc/sysconfig/ip6tables:

:INPUT DROP [0:0]

If changes were required, reload the ip6tables rules:

$ sudo service ip6tables reload

Rationale:

In ip6tables, the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy 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_ip6tables_default_rule

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
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
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, PR.PT-3
cis	3.5.3.3.1
pcidss4	1.4.1, 1.4

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if ( ! ( dpkg-query --show --showformat='${db:Status-Status}\n' 'nftables' 2>/dev/null | grep -q installed ) && ! ( dpkg-query --show --showformat='${db:Status-Status}\n' 'ufw' 2>/dev/null | grep -q installed ) && dpkg-query --show --showformat='${db:Status-Status}\n' 'iptables' 2>/dev/null | grep -q installed ); then

sed -i 's/^:INPUT ACCEPT.*/:INPUT DROP [0:0]/g' /etc/sysconfig/ip6tables

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

Rule Set configuration for IPv6 loopback traffic [ref]

Configure the loopback interface to accept traffic. Configure all other interfaces to deny traffic to the loopback network.

Warning: Changing firewall settings while connected over network can result in being locked out of the system.

Rationale:

Loopback traffic is generated between processes on machine and is typically critical to operation of the system. The loopback interface is the only place that loopback network traffic should be seen, all other interfaces should ignore traffic on this network as an anti-spoofing measure.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_set_ipv6_loopback_traffic

References:

pcidss	Req-1.3
cis	3.5.3.3.2
pcidss4	1.4.1, 1.4

Remediation Ansible snippet ⇲

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSS-Req-1.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.1
  - medium_severity
  - set_ipv6_loopback_traffic

- name: Check if IPv6 is enabled
  command: sysctl -n net.ipv6.conf.all.disable_ipv6
  register: ipv6_status
  failed_when: ipv6_status.stdout != "0"
  when: ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
    ) and "iptables" in ansible_facts.packages )
  tags:
  - PCI-DSS-Req-1.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.1
  - medium_severity
  - set_ipv6_loopback_traffic

- name: Allow incoming traffic on the loopback interface
  ansible.builtin.iptables:
    ipv6: true
    chain: INPUT
    in_interface: lo
    jump: ACCEPT
  when:
  - ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
    ) and "iptables" in ansible_facts.packages )
  - ipv6_status.stdout == '0'
  tags:
  - PCI-DSS-Req-1.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.1
  - medium_severity
  - set_ipv6_loopback_traffic

- name: Allow outgoing traffic on the loopback interface
  ansible.builtin.iptables:
    ipv6: true
    chain: OUTPUT
    out_interface: lo
    jump: ACCEPT
  when:
  - ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
    ) and "iptables" in ansible_facts.packages )
  - ipv6_status.stdout == '0'
  tags:
  - PCI-DSS-Req-1.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.1
  - medium_severity
  - set_ipv6_loopback_traffic

- name: Drop incoming traffic from the localhost
  ansible.builtin.iptables:
    ipv6: true
    chain: INPUT
    source: ::1
    jump: DROP
  when:
  - ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
    ) and "iptables" in ansible_facts.packages )
  - ipv6_status.stdout == '0'
  tags:
  - PCI-DSS-Req-1.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.1
  - medium_severity
  - set_ipv6_loopback_traffic

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if ( ! ( dpkg-query --show --showformat='${db:Status-Status}\n' 'nftables' 2>/dev/null | grep -q installed ) && ! ( dpkg-query --show --showformat='${db:Status-Status}\n' 'ufw' 2>/dev/null | grep -q installed ) && dpkg-query --show --showformat='${db:Status-Status}\n' 'iptables' 2>/dev/null | grep -q installed ); then

if [ "$(sysctl -n net.ipv6.conf.all.disable_ipv6)" -eq 0 ]; then
  # IPv6 is not disabled, so run the script
  ip6tables -A INPUT -i lo -j ACCEPT
  ip6tables -A OUTPUT -o lo -j ACCEPT
  ip6tables -A INPUT -s ::1 -j DROP
fi

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

Rule Set configuration for loopback traffic [ref]

Configure the loopback interface to accept traffic. Configure all other interfaces to deny traffic to the loopback network.

Warning: Changing firewall settings while connected over network can result in being locked out of the system.

Rationale:

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_set_loopback_traffic

References:

pcidss	Req-1.3
cis	3.5.3.2.2
pcidss4	1.4.1, 1.4

Remediation Ansible snippet ⇲

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - PCI-DSS-Req-1.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.1
  - medium_severity
  - set_loopback_traffic

- name: Allow incoming traffic on the loopback interface
  ansible.builtin.iptables:
    chain: INPUT
    in_interface: lo
    jump: ACCEPT
  when: ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
    ) and "iptables" in ansible_facts.packages )
  tags:
  - PCI-DSS-Req-1.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.1
  - medium_severity
  - set_loopback_traffic

- name: Allow outgoing traffic on the loopback interface
  ansible.builtin.iptables:
    chain: OUTPUT
    out_interface: lo
    jump: ACCEPT
  when: ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
    ) and "iptables" in ansible_facts.packages )
  tags:
  - PCI-DSS-Req-1.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.1
  - medium_severity
  - set_loopback_traffic

- name: Drop incoming traffic from the localhost
  ansible.builtin.iptables:
    chain: INPUT
    source: 127.0.0.0/8
    jump: DROP
  when: ( not ( "nftables" in ansible_facts.packages ) and not ( "ufw" in ansible_facts.packages
    ) and "iptables" in ansible_facts.packages )
  tags:
  - PCI-DSS-Req-1.3
  - PCI-DSSv4-1.4
  - PCI-DSSv4-1.4.1
  - medium_severity
  - set_loopback_traffic

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if ( ! ( dpkg-query --show --showformat='${db:Status-Status}\n' 'nftables' 2>/dev/null | grep -q installed ) && ! ( dpkg-query --show --showformat='${db:Status-Status}\n' 'ufw' 2>/dev/null | grep -q installed ) && dpkg-query --show --showformat='${db:Status-Status}\n' 'iptables' 2>/dev/null | grep -q installed ); then

iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT
iptables -A INPUT -s 127.0.0.0/8 -j DROP

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

Group Strengthen the Default Ruleset Group contains 3 rules

[ref] The default rules can be strengthened. The system scripts that activate the firewall rules expect them to be defined in the configuration files iptables and ip6tables in the directory /etc/sysconfig. Many of the lines in these files are similar to the command line arguments that would be provided to the programs /sbin/iptables or /sbin/ip6tables - but some are quite different.

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 iptables program to load in rules, and then invokes service iptables save to write those loaded rules to /etc/sysconfig/iptables.

The following alterations can be made directly to /etc/sysconfig/iptables and /etc/sysconfig/ip6tables. Instructions apply to both unless otherwise noted. Language and address conventions for regular iptables are used throughout this section; configuration for ip6tables will be either analogous or explicitly covered.

Warning: The program system-config-securitylevel allows additional services to penetrate the default firewall rules and automatically adjusts /etc/sysconfig/iptables. This program is only useful if the default ruleset meets your security requirements. Otherwise, this program should not be used to make changes to the firewall configuration because it re-writes the saved configuration file.

Rule Ensure ip6tables Firewall Rules Exist for All Open Ports [ref]

Any ports that have been opened on non-loopback addresses need firewall rules to govern traffic.

Warning: Changing firewall settings while connected over network can result in being locked out of the system.

Rationale:

Without a firewall rule configured for open ports default firewall policy will drop all packets to these ports.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_ip6tables_rules_for_open_ports

References:

cis	3.5.3.3.4

Rule Ensure iptables Firewall Rules Exist for All Open Ports [ref]

Any ports that have been opened on non-loopback addresses need firewall rules to govern traffic.

Warning: Changing firewall settings while connected over network can result in being locked out of the system.

Rationale:

Without a firewall rule configured for open ports default firewall policy will drop all packets to these ports.

Severity:

medium

Rule ID:

xccdf_org.ssgproject.content_rule_iptables_rules_for_open_ports

References:

cis	3.5.3.2.4

Rule Set Default iptables Policy for Incoming Packets [ref]

To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following line in /etc/sysconfig/iptables:

:INPUT DROP [0:0]

Rationale:

In iptables the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy 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_iptables_default_rule

References:

cis-csc	11, 14, 3, 9
cobit5	BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06
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	CA-3(5), CM-7(b), SC-7(23), CM-6(a)
nist-csf	PR.IP-1, PR.PT-3
cis	3.5.3.2.1

Remediation Shell script ⇲

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'iptables' 2>/dev/null | grep -q installed && { ( ! ( dpkg-query --show --showformat='${db:Status-Status}\n' 'nftables' 2>/dev/null | grep -q installed ) && ! ( dpkg-query --show --showformat='${db:Status-Status}\n' 'ufw' 2>/dev/null | grep -q installed ) ); }; then

sed -i 's/^:INPUT ACCEPT.*/:INPUT DROP [0:0]/g' /etc/sysconfig/iptables

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

Rule Install iptables Package [ref]

The iptables package can be installed with the following command:

$ apt-get install iptables

Rationale:

iptables controls the Linux kernel network packet filtering code. iptables allows system operators to set up firewalls and IP masquerading, etc.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_iptables_installed

References:

nist	CM-6(a)
pcidss	Req-1.4.1
os-srg	SRG-OS-000480-GPOS-00227
cis	3.5.3.1.1

Remediation Puppet snippet ⇲

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

include install_iptables

class install_iptables {
  package { 'iptables':
    ensure => 'installed',
  }
}

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)
  - PCI-DSS-Req-1.4.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_iptables_installed

- name: Ensure iptables is installed
  package:
    name: iptables
    state: present
  when: ( "linux-base" in ansible_facts.packages )
  tags:
  - NIST-800-53-CM-6(a)
  - PCI-DSS-Req-1.4.1
  - enable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_iptables_installed

Remediation OSBuild Blueprint snippet ⇲


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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if ( dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed ); then

DEBIAN_FRONTEND=noninteractive apt-get install -y "iptables"

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

Rule Remove iptables-persistent Package [ref]

The iptables-persistent package can be removed with the following command:

$ apt-get remove iptables-persistent

Rationale:

Running both ufw and the services included in the iptables-persistent package may lead to conflict.

Severity:

medium

Rule ID: xccdf_org.ssgproject.content_rule_package_iptables-persistent_removed

References:

cis	3.5.1.2

Remediation Puppet snippet ⇲

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

include remove_iptables-persistent

class remove_iptables-persistent {
  package { 'iptables-persistent':
    ensure => 'purged',
  }
}

Remediation Ansible snippet ⇲

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_iptables-persistent_removed

- name: Ensure iptables-persistent is removed
  package:
    name: iptables-persistent
    state: absent
  when: '"ufw" in ansible_facts.packages'
  tags:
  - disable_strategy
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed
  - package_iptables-persistent_removed

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}\n' 'ufw' 2>/dev/null | grep -q installed; then

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

DEBIAN_FRONTEND=noninteractive apt-get remove -y "iptables-persistent"

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

Group IPv6 Group contains 1 group and 7 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 Configure IPv6 Settings if Necessary Group contains 7 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 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
cis	3.3.9

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/
    contains: ^[\s]*net.ipv6.conf.all.accept_ra.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"linux-base" 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: '"linux-base" 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: '"linux-base" 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; 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; 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

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
cis	3.3.2
anssi	R13

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/
    contains: ^[\s]*net.ipv6.conf.all.accept_redirects.*$
    patterns: '*.conf'
    file_type: any
  register: find_sysctl_d
  when: '"linux-base" 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: '"linux-base" 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: '"linux-base" 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

Remediation Shell script ⇲

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

# Remediation is applicable only in certain platforms
if dpkg-query --show --showformat='${db:Status-Status}
' 'linux-base' 2>/dev/null | grep -q ^installed; 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; 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