Group
Guide to the Secure Configuration of Ubuntu 22.04
Group contains 113 groups and 388 rules |
Group
System Settings
Group contains 57 groups and 216 rules |
[ref]
Contains rules that check correct system settings. |
Group
Installing and Maintaining Software
Group contains 9 groups and 26 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 |
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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 |
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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 |
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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 |
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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: | | |
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Group
Disk Partitioning
Group contains 6 rules |
[ref]
To ensure separation and protection of data, there
are top-level system directories which should be placed on their
own physical partition or logical volume. The installer's default
partitioning scheme creates separate logical volumes for
/ , /boot , and swap .
- If starting with any of the default layouts, check the box to
\"Review and modify partitioning.\" This allows for the easy creation
of additional logical volumes inside the volume group already
created, though it may require making
/ 's logical volume smaller to
create space. In general, using logical volumes is preferable to
using partitions because they can be more easily adjusted
later. - If creating a custom layout, create the partitions mentioned in
the previous paragraph (which the installer will require anyway),
as well as separate ones described in the following sections.
If a system has already been installed, and the default
partitioning
scheme was used, it is possible but nontrivial to
modify it to create separate logical volumes for the directories
listed above. The Logical Volume Manager (LVM) makes this possible. |
Rule
Ensure /home Located On Separate Partition
[ref] | If user home directories will be stored locally, create a separate partition
for /home at installation time (or migrate it later using LVM). If
/home will be mounted from another system such as an NFS server, then
creating a separate partition is not necessary at installation time, and the
mountpoint can instead be configured later. | Rationale: | Ensuring that /home is mounted on its own partition enables the
setting of more restrictive mount options, and also helps ensure that
users cannot trivially fill partitions used for log or audit data storage. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_home | References: | cis-csc | 12, 15, 8 | cobit5 | APO13.01, DSS05.02 | disa | CCI-000366 | isa-62443-2013 | SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6 | iso27001-2013 | A.13.1.1, A.13.2.1, A.14.1.3 | nist | CM-6(a), SC-5(2) | nist-csf | PR.PT-4 | os-srg | SRG-OS-000480-GPOS-00227 | cis | 1.1.7.1 | anssi | R28 |
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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 |
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Rule
Ensure /var Located On Separate Partition
[ref] | The /var directory is used by daemons and other system
services to store frequently-changing data. Ensure that /var has its own partition
or logical volume at installation time, or migrate it using LVM. | Rationale: | Ensuring that /var is mounted on its own partition enables the
setting of more restrictive mount options. This helps protect
system services such as daemons or other programs which use it.
It is not uncommon for the /var directory to contain
world-writable directories installed by other software packages. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_var | References: | cis-csc | 12, 15, 8 | cobit5 | APO13.01, DSS05.02 | disa | CCI-000366 | isa-62443-2013 | SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6 | iso27001-2013 | A.13.1.1, A.13.2.1, A.14.1.3 | nist | CM-6(a), SC-5(2) | nist-csf | PR.PT-4 | os-srg | SRG-OS-000480-GPOS-00227 | cis | 1.1.3.1 | anssi | R28 |
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Rule
Ensure /var/log Located On Separate Partition
[ref] | System logs are stored in the /var/log directory.
Ensure that /var/log has its own partition or logical
volume at installation time, or migrate it using LVM. | Rationale: | Placing /var/log in its own partition
enables better separation between log files
and other files in /var/ . | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_var_log | References: | cis-csc | 1, 12, 14, 15, 16, 3, 5, 6, 8 | cobit5 | APO11.04, APO13.01, BAI03.05, DSS05.02, DSS05.04, DSS05.07, MEA02.01 | disa | CCI-000366 | isa-62443-2009 | 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4 | isa-62443-2013 | SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6 | iso27001-2013 | A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3 | nerc-cip | CIP-007-3 R6.5 | nist | CM-6(a), AU-4, SC-5(2) | nist-csf | PR.PT-1, PR.PT-4 | os-srg | SRG-OS-000480-GPOS-00227 | cis | 1.1.5.1 | anssi | R28 |
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Rule
Ensure /var/log/audit Located On Separate Partition
[ref] | Audit logs are stored in the /var/log/audit directory.
Ensure that /var/log/audit has its own partition or logical
volume at installation time, or migrate it using LVM.
Make absolutely certain that it is large enough to store all
audit logs that will be created by the auditing daemon. | Rationale: | Placing /var/log/audit in its own partition
enables better separation between audit files
and other files, and helps ensure that
auditing cannot be halted due to the partition running out
of space. | Severity: | low | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_var_log_audit | References: | cis-csc | 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 8 | cobit5 | APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.02, DSS05.04, DSS05.07, MEA02.01 | disa | CCI-000366, CCI-001849 | hipaa | 164.312(a)(2)(ii) | isa-62443-2009 | 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4 | isa-62443-2013 | SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.2, SR 7.6 | iso27001-2013 | A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.17.2.1 | nerc-cip | CIP-007-3 R6.5 | nist | CM-6(a), AU-4, SC-5(2) | nist-csf | PR.DS-4, PR.PT-1, PR.PT-4 | ospp | FMT_SMF_EXT.1 | os-srg | SRG-OS-000341-GPOS-00132, SRG-OS-000480-GPOS-00227 | app-srg-ctr | SRG-APP-000357-CTR-000800 | cis | 1.1.6.1 | anssi | R71 |
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Rule
Ensure /var/tmp Located On Separate Partition
[ref] | The /var/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 /var/tmp partition is used as temporary storage by many programs.
Placing /var/tmp in its own partition enables the setting of more
restrictive mount options, which can help protect programs which use it. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_partition_for_var_tmp | References: | | |
|
Group
GNOME Desktop Environment
Group contains 3 groups and 9 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 |
|
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: | | |
|
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: | | |
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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 |
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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 |
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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 |
| |
|
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 |
| |
|
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: | 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_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 |
| |
|
Rule
Remove the GDM Package Group
[ref] |
By removing the gdm3 package, the system no longer has GNOME installed
installed. If X Windows is not installed then the system cannot boot into graphical user mode.
This prevents the system from being accidentally or maliciously booted into a graphical.target
mode. To do so, run the following command:
$ sudo apt remove gdm3
| Rationale: | Unnecessary service packages must not be installed to decrease the attack surface of the system.
A graphical environment is unnecessary for certain types of systems including a virtualization
hypervisor. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_package_gdm_removed | References: | nist | CM-7(a), CM-7(b), CM-6(a) | os-srg | SRG-OS-000480-GPOS-00227 | cis | 1.8.1 |
| |
|
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: | | |
|
Group
Sudo
Group contains 6 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: | | |
|
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: | | |
|
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: | | |
|
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 |
| |
|
Rule
Ensure Users Re-Authenticate for Privilege Escalation - sudo
[ref] | The sudo NOPASSWD and !authenticate option, when
specified, allows a user to execute commands using sudo without having to
authenticate. This should be disabled by making sure that
NOPASSWD and/or !authenticate do 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_require_authentication | References: | cis-csc | 1, 12, 15, 16, 5 | cobit5 | DSS05.04, DSS05.10, DSS06.03, DSS06.10 | disa | CCI-002038, 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 | stigid | UBTU-22-432010 | cis | 5.3.4 | pcidss4 | 2.2.6, 2.2 | stigref | SV-260558r987879_rule |
| |
|
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: | 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_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 |
| |
|
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 |
| |
|
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 |
| |
|
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 |
| |
|
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 |
| |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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. |
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 |
| |
|
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. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. | Rationale: | By limiting the number of failed logon attempts, the risk of unauthorized system access via
user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking
the account. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_deny | References: | cis-csc | 1, 12, 15, 16 | cjis | 5.5.3 | cobit5 | DSS05.04, DSS05.10, DSS06.10 | cui | 3.1.8 | disa | CCI-000044, CCI-002238 | isa-62443-2009 | 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9 | isa-62443-2013 | SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9 | ism | 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561 | iso27001-2013 | A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3 | nist | CM-6(a), AC-7(a) | nist-csf | PR.AC-7 | ospp | FIA_AFL.1 | pcidss | Req-8.1.6 | os-srg | SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005 | stigid | UBTU-22-411045 | cis | 5.4.2 | anssi | R31 | pcidss4 | 8.3.4, 8.3 | stigref | SV-260549r958388_rule |
| |
|
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. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. | Rationale: | By limiting the number of failed logon attempts the risk of unauthorized system
access via user password guessing, 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 |
| |
|
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. Warning:
If the system relies on authselect tool to manage PAM settings, the remediation
will also use authselect tool. However, if any manual modification was made in
PAM files, the authselect integrity check will fail and the remediation will be
aborted in order to preserve intentional changes. In this case, an informative message will
be shown in the remediation report.
If the system supports the /etc/security/faillock.conf file, the pam_faillock
parameters should be defined in faillock.conf file. | Rationale: | By limiting the number of failed logon attempts the risk of unauthorized system
access via user password guessing, 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_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 |
| |
|
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 |
| |
|
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 |
| |
|
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 |
| |
|
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 |
| |
|
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 |
| |
|
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 |
| |
|
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: | 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. | 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 |
| |
|
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 |
| |
|
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: | | |
|
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 |
| |
|
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: | | |
|
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: | | |
|
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 |
| |
|
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 |
| |
|
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: | 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. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_set_max_life_existing | References: | | |
|
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 |
| |
|
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 |
| |
|
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: | | |
|
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: | | |
|
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: | | |
|
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 |
| |
|
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: | | |
|
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: | | |
|
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: | | |
|
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 |
| |
|
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: | 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_use_pam_wheel_group_for_su | References: | | |
|
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: | | |
|
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: | | |
|
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 |
| |
|
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: | The umask value influences the permissions assigned to files when they are created.
A misconfigured umask value could result in files with excessive permissions that can be read and
written to by unauthorized users. | Severity: | medium | Rule ID: | xccdf_org.ssgproject.content_rule_accounts_umask_etc_login_defs | References: | cis-csc | 11, 18, 3, 9 | cobit5 | APO13.01, BAI03.01, BAI03.02, BAI03.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05 | disa | CCI-000366 | isa-62443-2009 | 4.3.4.3.2, 4.3.4.3.3 | isa-62443-2013 | SR 7.6 | iso27001-2013 | A.12.1.2, A.12.5.1, A.12.6.2, A.14.1.1, A.14.2.1, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.5, A.6.1.5 | nerc-cip | CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2 | nist | AC-6(1), CM-6(a) | nist-csf | PR.IP-1, PR.IP-2 | os-srg | SRG-OS-000480-GPOS-00228 | stigid | UBTU-22-412035 | cis | 5.5.4 | anssi | R36 | stigref | SV-260555r991590_rule |
| |
|
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: | 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_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 |
| |
|
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 |
| |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
Group
AppArmor
Group contains 4 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 |
| |
|
Rule
Enforce all AppArmor Profiles
[ref] | AppArmor profiles define what resources applications are able to access.
To set all profiles to enforce mode run the following command:
$ sudo aa-enforce /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_enforced | References: | | |
|
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: | | |
|
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: | | |
|
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 |
| |
|
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 |
| |
|
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] | 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_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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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: | | |
|
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 |
| |
|
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 |
| |
|
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 |
| |
|
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 |
| |
|
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: | | |
|
Group
Network Configuration and Firewalls
Group contains 13 groups and 48 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 |
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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: | | |
|
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: | 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_loopback_traffic | References: | | |
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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: | | |
|
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: | | |
|
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 |
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