## Guide to the Secure Configuration of Debian 11

> with profile Profile for ANSSI DAT-NT28 High (Enforced) Level
> This profile contains items for GNU/Linux installations storing sensitive informations that can be accessible from unauthenticated or uncontroled networks.

The SCAP Security Guide Project
https://www.open-scap.org/security-policies/scap-security-guide
This guide presents a catalog of security-relevant configuration settings for Debian 11. It is a rendering of content structured in the eXtensible Configuration Checklist Description Format (XCCDF) in order to support security automation. The SCAP content is is available in the `scap-security-guide` package which is developed at https://www.open-scap.org/security-policies/scap-security-guide.
Providing system administrators with such guidance informs them how to securely configure systems under their control in a variety of network roles. Policy makers and baseline creators can use this catalog of settings, with its associated references to higher-level security control catalogs, in order to assist them in security baseline creation. This guide is a catalog, not a checklist, and satisfaction of every item is not likely to be possible or sensible in many operational scenarios. However, the XCCDF format enables granular selection and adjustment of settings, and their association with OVAL and OCIL content provides an automated checking capability. Transformations of this document, and its associated automated checking content, are capable of providing baselines that meet a diverse set of policy objectives. Some example XCCDF Profiles, which are selections of items that form checklists and can be used as baselines, are available with this guide. They can be processed, in an automated fashion, with tools that support the Security Content Automation Protocol (SCAP). The DISA STIG, which provides required settings for US Department of Defense systems, is one example of a baseline created from this guidance.
Do not attempt to implement any of the settings in this guide without first testing them in a non-operational environment. The creators of this guidance assume no responsibility whatsoever for its use by other parties, and makes no guarantees, expressed or implied, about its quality, reliability, or any other characteristic.

## Profile Information

Profile Title | Profile for ANSSI DAT-NT28 High (Enforced) Level
Profile ID | xccdf_org.ssgproject.content_profile_anssi_np_nt28_high

#### CPE Platforms

- cpe:/o:debian:debian_linux:11

## Revision History

Current version: 0.1.61

- draft (as of 2022-04-01)

## Table of Contents

1. System Settings
   1. Installing and Maintaining Software
   2. System Accounting with auditd
   3. GRUB2 bootloader configuration
   4. Configure Syslog
   5. File Permissions and Masks
2. Services
   1. APT service configuration
   2. Cron and At Daemons
   3. Deprecated services
   4. Network Time Protocol
   5. SSH Server

## Checklist

Group Guide to the Secure Configuration of Debian 11 Group contains 23 groups and 50 rules
Group System Settings Group contains 15 groups and 35 rules
[ref] Contains rules that check correct system settings.
Group Installing and Maintaining Software Group contains 2 groups and 7 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 Disk Partitioning Group contains 5 rules
[ref] To ensure separation and protection of data, there are top-level system directories which should be placed on their own physical partition or logical volume. The installer's default partitioning scheme creates separate logical volumes for `/`, `/boot`, and `swap`. If starting with any of the default layouts, check the box to \"Review and modify partitioning.\" This allows for the easy creation of additional logical volumes inside the volume group already created, though it may require making `/`'s logical volume smaller to create space. In general, using logical volumes is preferable to using partitions because they can be more easily adjusted later. If creating a custom layout, create the partitions mentioned in the previous paragraph (which the installer will require anyway), as well as separate ones described in the following sections. If a system has already been installed, and the default partitioning scheme was used, it is possible but nontrivial to modify it to create separate logical volumes for the directories listed above. The Logical Volume Manager (LVM) makes this possible. See the LVM HOWTO at http://tldp.org/HOWTO/LVM-HOWTO/ for more detailed information on LVM.
#### 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
Identifiers and References | References: BP28(R12), 12, 15, 8, APO13.01, DSS05.02, CCI-000366, CCI-001208, 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, A.13.1.1, A.13.2.1, A.14.1.3, CM-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227
#### 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
Identifiers and References | References: BP28(R12), 12, 15, 8, APO13.01, DSS05.02, CCI-000366, 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, A.13.1.1, A.13.2.1, A.14.1.3, CM-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227
#### 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
Identifiers and References | References: BP28(R12), 12, 15, 8, APO13.01, DSS05.02, CCI-000366, 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, A.13.1.1, A.13.2.1, A.14.1.3, CM-6(a), SC-5(2), PR.PT-4, SRG-OS-000480-GPOS-00227, SRG-OS-000341-VMM-001220
#### 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
Identifiers and References | References: BP28(R12), BP28(R47), 1, 12, 14, 15, 16, 3, 5, 6, 8, APO11.04, APO13.01, BAI03.05, DSS05.02, DSS05.04, DSS05.07, MEA02.01, CCI-000366, 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, 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, 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, CIP-007-3 R6.5, CM-6(a), AU-4, SC-5(2), PR.PT-1, PR.PT-4, SRG-OS-000480-GPOS-00227
#### 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
Identifiers and References | References: BP28(R43), 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 8, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.02, DSS05.04, DSS05.07, MEA02.01, CCI-000366, CCI-001849, 164.312(a)(2)(ii), 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, 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, 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, CIP-007-3 R6.5, CM-6(a), AU-4, SC-5(2), PR.DS-4, PR.PT-1, PR.PT-4, SRG-OS-000341-GPOS-00132, SRG-OS-000480-GPOS-00227, SRG-OS-000341-VMM-001220
Group Sudo Group contains 2 rules
[ref] `Sudo`, which stands for "su 'do'", provides the ability to delegate authority to certain users, groups of users, or system administrators. When configured for system users and/or groups, `Sudo` can allow a user or group to execute privileged commands that normally only `root` is allowed to execute. For more information on `Sudo` and addition `Sudo` configuration options, see https://www.sudo.ws.
#### Rule Ensure Users Re-Authenticate for Privilege Escalation - sudo !authenticate [ref]
The sudo `!authenticate` option, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that the `!authenticate` option does not exist in `/etc/sudoers` configuration file or any sudo configuration snippets in `/etc/sudoers.d/`.
Rationale: | Without re-authentication, users may access resources or perform tasks for which they do not have authorization. When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sudo_remove_no_authenticate
Identifiers and References | References: BP28(R5), BP28(R59), 1, 12, 15, 16, 5, DSS05.04, DSS05.10, DSS06.03, DSS06.10, CCI-002038, 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, 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, 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, IA-11, CM-6(a), PR.AC-1, PR.AC-7, SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158, SRG-OS-000373-VMM-001470, SRG-OS-000373-VMM-001480, SRG-OS-000373-VMM-001490
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    for f in /etc/sudoers /etc/sudoers.d/* ; do
      if [ ! -e "$f" ] ; then
        continue
      fi
      matching_list=$(grep -P '^(?!#).*[\s]+\!authenticate.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          # comment out "!authenticate" matches to preserve user data
          sed -i "s/^${entry}$/# &/g" $f
        done <<< "$matching_list"

        /usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
      fi
    done
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    - name: Find /etc/sudoers.d/ files
      find:
        paths:
          - /etc/sudoers.d/
      register: sudoers
      tags:
        - NIST-800-53-CM-6(a)
        - NIST-800-53-IA-11
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - restrict_strategy
        - sudo_remove_no_authenticate

    - name: Remove lines containing !authenticate from sudoers files
      replace:
        regexp: (^(?!#).*[\s]+\!authenticate.*$)
        replace: '# \g<1>'
        path: '{{ item.path }}'
        validate: /usr/sbin/visudo -cf %s
      with_items:
        - path: /etc/sudoers
        - '{{ sudoers.files }}'
      tags:
        - NIST-800-53-CM-6(a)
        - NIST-800-53-IA-11
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - restrict_strategy
        - sudo_remove_no_authenticate
#### Rule Ensure Users Re-Authenticate for Privilege Escalation - sudo NOPASSWD [ref]
The sudo `NOPASSWD` tag, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that the `NOPASSWD` tag does not exist in `/etc/sudoers` configuration file or any sudo configuration snippets in `/etc/sudoers.d/`.
Rationale: | Without re-authentication, users may access resources or perform tasks for which they do not have authorization. When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sudo_remove_nopasswd
Identifiers and References | References: BP28(R5), BP28(R59), 1, 12, 15, 16, 5, DSS05.04, DSS05.10, DSS06.03, DSS06.10, CCI-002038, 4.3.3.5.1, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-11, CM-6(a), PR.AC-1, PR.AC-7, SRG-OS-000373-GPOS-00156, SRG-OS-000373-GPOS-00157, SRG-OS-000373-GPOS-00158, SRG-OS-000373-VMM-001470, SRG-OS-000373-VMM-001480, SRG-OS-000373-VMM-001490
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    for f in /etc/sudoers /etc/sudoers.d/* ; do
      if [ ! -e "$f" ] ; then
        continue
      fi
      matching_list=$(grep -P '^(?!#).*[\s]+NOPASSWD[\s]*\:.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          # comment out "NOPASSWD" matches to preserve user data
          sed -i "s/^${entry}$/# &/g" $f
        done <<< "$matching_list"

        /usr/sbin/visudo -cf $f &> /dev/null || echo "Fail to validate $f with visudo"
      fi
    done
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    - name: Find /etc/sudoers.d/ files
      find:
        paths:
          - /etc/sudoers.d/
      register: sudoers
      tags:
        - NIST-800-53-CM-6(a)
        - NIST-800-53-IA-11
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - restrict_strategy
        - sudo_remove_nopasswd

    - name: Remove lines containing NOPASSWD from sudoers files
      replace:
        regexp: (^(?!#).*[\s]+NOPASSWD[\s]*\:.*$)
        replace: '# \g<1>'
        path: '{{ item.path }}'
        validate: /usr/sbin/visudo -cf %s
      with_items:
        - path: /etc/sudoers
        - '{{ sudoers.files }}'
      tags:
        - NIST-800-53-CM-6(a)
        - NIST-800-53-IA-11
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - restrict_strategy
        - sudo_remove_nopasswd
Group System Accounting with auditd Group contains 2 rules
[ref] The audit service provides substantial capabilities for recording system activities. By default, the service audits about SELinux AVC denials and certain types of security-relevant events such as system logins, account modifications, and authentication events performed by programs such as sudo. Under its default configuration, `auditd` has modest disk space requirements, and should not noticeably impact system performance. NOTE: The Linux Audit daemon `auditd` can be configured to use the `augenrules` program to read audit rules files (`*.rules`) located in `/etc/audit/rules.d` location and compile them to create the resulting form of the `/etc/audit/audit.rules` configuration file during the daemon startup (default configuration). Alternatively, the `auditd` daemon can use the `auditctl` utility to read audit rules from the `/etc/audit/audit.rules` configuration file during daemon startup, and load them into the kernel. The expected behavior is configured via the appropriate `ExecStartPost` directive setting in the `/usr/lib/systemd/system/auditd.service` configuration file. To instruct the `auditd` daemon to use the `augenrules` program to read audit rules (default configuration), use the following setting:
    ExecStartPost=-/sbin/augenrules --load
in the `/usr/lib/systemd/system/auditd.service` configuration file. In order to instruct the `auditd` daemon to use the `auditctl` utility to read audit rules, use the following setting:
    ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules
in the `/usr/lib/systemd/system/auditd.service` configuration file. Refer to `[Service]` section of the `/usr/lib/systemd/system/auditd.service` configuration file for further details. Government networks often have substantial auditing requirements and `auditd` can be configured to meet these requirements. Examining some example audit records demonstrates how the Linux audit system satisfies common requirements. The following example from Fedora Documentation available at `https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/selinux_users_and_administrators_guide/index#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages` shows the substantial amount of information captured in a two typical "raw" audit messages, followed by a breakdown of the most important fields. In this example the message is SELinux-related and reports an AVC denial (and the associated system call) that occurred when the Apache HTTP Server attempted to access the `/var/www/html/file1` file (labeled with the `samba_share_t` type):
    type=AVC msg=audit(1226874073.147:96): avc:  denied  { getattr } for pid=2465 comm="httpd"
    path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
    tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

    type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
    a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
    gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
    exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)
`msg=audit(1226874073.147:96)` The number in parentheses is the unformatted time stamp (Epoch time) for the event, which can be converted to standard time by using the `date` command. `{ getattr }` The item in braces indicates the permission that was denied. `getattr` indicates the source process was trying to read the target file's status information. This occurs before reading files. This action is denied due to the file being accessed having the wrong label. Commonly seen permissions include `getattr`, `read`, and `write`. `comm="httpd"` The executable that launched the process. The full path of the executable is found in the `exe=` section of the system call (`SYSCALL`) message, which in this case, is `exe="/usr/sbin/httpd"`. `path="/var/www/html/file1"` The path to the object (target) the process attempted to access. `scontext="unconfined_u:system_r:httpd_t:s0"` The SELinux context of the process that attempted the denied action. In this case, it is the SELinux context of the Apache HTTP Server, which is running in the `httpd_t` domain. `tcontext="unconfined_u:object_r:samba_share_t:s0"` The SELinux context of the object (target) the process attempted to access. In this case, it is the SELinux context of `file1`. Note: the `samba_share_t` type is not accessible to processes running in the `httpd_t` domain. From the system call (`SYSCALL`) message, two items are of interest: `success=no`: indicates whether the denial (AVC) was enforced or not. `success=no` indicates the system call was not successful (SELinux denied access). `success=yes` indicates the system call was successful - this can be seen for permissive domains or unconfined domains, such as `initrc_t` and `kernel_t`. `exe="/usr/sbin/httpd"`: the full path to the executable that launched the process, which in this case, is `exe="/usr/sbin/httpd"`.
#### Rule Ensure the audit Subsystem is Installed [ref]
The audit package should be installed.
Rationale: | The auditd service is an access monitoring and accounting daemon, watching system calls to audit any access, in comparison with potential local access control policy such as SELinux policy.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_audit_installed
Identifiers and References | References: BP28(R50), CCI-000172, CCI-001814, CCI-001875, CCI-001877, CCI-001878, CCI-001879, CCI-001880, CCI-001881, CCI-001882, CCI-001889, CCI-001914, CCI-000169, CIP-004-6 R3.3, CIP-007-3 R6.5, AC-7(a), AU-7(1), AU-7(2), AU-14, AU-12(2), AU-2(a), CM-6(a), FAU_GEN.1, SRG-OS-000122-GPOS-00063, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000359-GPOS-00146, SRG-OS-000365-GPOS-00152, SRG-OS-000474-GPOS-00219, SRG-OS-000475-GPOS-00220, SRG-OS-000480-GPOS-00227, SRG-OS-000062-GPOS-00031
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    - name: Ensure auditd is installed
      package:
        name: auditd
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AC-7(a)
        - NIST-800-53-AU-12(2)
        - NIST-800-53-AU-14
        - NIST-800-53-AU-2(a)
        - NIST-800-53-AU-7(1)
        - NIST-800-53-AU-7(2)
        - NIST-800-53-CM-6(a)
        - enable_strategy
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - package_audit_installed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    include install_auditd

    class install_auditd {
      package { 'auditd':
        ensure => 'installed',
      }
    }
Remediation script ⇲
    [[packages]]
    name = "auditd"
    version = "*"
#### Rule Enable auditd Service [ref]
The `auditd` service is an essential userspace component of the Linux Auditing System, as it is responsible for writing audit records to disk. The `auditd` service can be enabled with the following command:
    $ sudo systemctl enable auditd.service
Rationale: | Without establishing what type of events occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Ensuring the `auditd` service is active ensures audit records generated by the kernel are appropriately recorded. Additionally, a properly configured audit subsystem ensures that actions of individual system users can be uniquely traced to those users so they can be held accountable for their actions.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_auditd_enabled
Identifiers and References | References: 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.3.2, 3.3.6, CCI-000126, CCI-000130, CCI-000131, CCI-000132, CCI-000133, CCI-000134, CCI-000135, CCI-000154, CCI-000158, CCI-000366, CCI-001464, CCI-001487, CCI-001814, CCI-001876, CCI-002884, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, CIP-004-6 R3.3, CIP-007-3 R6.5, AC-2(g), AU-3, AU-10, AU-2(d), AU-12(c), AU-14(1), AC-6(9), CM-6(a), SI-4(23), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1, Req-10.1, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000480-GPOS-00227, SRG-OS-000062-GPOS-00031, SRG-OS-000037-VMM-000150, SRG-OS-000063-VMM-000310, SRG-OS-000038-VMM-000160, SRG-OS-000039-VMM-000170, SRG-OS-000040-VMM-000180, SRG-OS-000041-VMM-000190
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
        - CJIS-5.4.1.1
        - NIST-800-171-3.3.1
        - NIST-800-171-3.3.2
        - NIST-800-171-3.3.6
        - NIST-800-53-AC-2(g)
        - NIST-800-53-AC-6(9)
        - NIST-800-53-AU-10
        - NIST-800-53-AU-12(c)
        - NIST-800-53-AU-14(1)
        - NIST-800-53-AU-2(d)
        - NIST-800-53-AU-3
        - NIST-800-53-CM-6(a)
        - NIST-800-53-SI-4(23)
        - PCI-DSS-Req-10.1
        - enable_strategy
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - service_auditd_enabled

    - name: Enable service auditd
      block:

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

        - name: Enable service auditd
          service:
            name: auditd
            enabled: 'yes'
            state: started
            masked: 'no'
          when:
            - '"auditd" in ansible_facts.packages'
      when:
        - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        - '"audit" in ansible_facts.packages'
      tags:
        - CJIS-5.4.1.1
        - NIST-800-171-3.3.1
        - NIST-800-171-3.3.2
        - NIST-800-171-3.3.6
        - NIST-800-53-AC-2(g)
        - NIST-800-53-AC-6(9)
        - NIST-800-53-AU-10
        - NIST-800-53-AU-12(c)
        - NIST-800-53-AU-14(1)
        - NIST-800-53-AU-2(d)
        - NIST-800-53-AU-3
        - NIST-800-53-CM-6(a)
        - NIST-800-53-SI-4(23)
        - PCI-DSS-Req-10.1
        - enable_strategy
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - service_auditd_enabled
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    include enable_auditd

    class enable_auditd {
      service {'auditd':
        enable => true,
        ensure => 'running',
      }
    }
Remediation script ⇲
    [customizations.services]
    enabled = ["auditd"]
Group GRUB2 bootloader configuration Group contains 1 rule
[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 Debian 11 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.
#### Rule IOMMU configuration directive [ref]
On x86 architecture supporting VT-d, the IOMMU manages the access control policy between the hardware devices and some of the system critical units such as the memory. Configure the default Grub2 kernel command line to contain iommu=force as follows:
    # grub2-editenv - set "$(grub2-editenv - list | grep kernelopts) iommu=force"
Warning: Depending on the hardware, devices and operating system used, enabling IOMMU can cause hardware instabilities. Proper function and stability should be assessed before applying remediation to production systems.
Rationale: | On x86 architectures, activating the I/OMMU prevents the system from arbitrary accesses potentially made by hardware devices.
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_enable_iommu_force
Identifiers and References | References: BP28(R11)
Group Configure Syslog Group contains 3 groups and 8 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 Debian 11, rsyslog has replaced ksyslogd as the syslog daemon of choice, and it includes some additional security features such as reliable, connection-oriented (i.e. TCP) transmission of logs, the option to log to database formats, and the encryption of log data en route to a central logging server. This section discusses how to configure rsyslog for best effect, and how to use tools provided with the system to maintain and monitor logs.
Group Ensure Proper Configuration of Log Files Group contains 3 rules
[ref] The file `/etc/rsyslog.conf` controls where log message are written. These are controlled by lines called rules, which consist of a selector and an action. These rules are often customized depending on the role of the system, the requirements of the environment, and whatever may enable the administrator to most effectively make use of log data. The default rules in Debian 11 are:
    *.info;mail.none;authpriv.none;cron.none                /var/log/messages
    authpriv.*                                              /var/log/secure
    mail.*                                                  -/var/log/maillog
    cron.*                                                  /var/log/cron
    *.emerg                                                 *
    uucp,news.crit                                          /var/log/spooler
    local7.*                                                /var/log/boot.log
See the man page `rsyslog.conf(5)` for more information. Note that the `rsyslog` daemon can be configured to use a timestamp format that some log processing programs may not understand. If this occurs, edit the file `/etc/rsyslog.conf` and add or edit the following line:
    $ ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat
#### Rule Ensure Log Files Are Owned By Appropriate Group [ref]
The group-owner of all log files written by `rsyslog` should be `adm`. These log files are determined by the second part of each Rule line in `/etc/rsyslog.conf` and typically all appear in `/var/log`. For each log file LOGFILE referenced in `/etc/rsyslog.conf`, run the following command to inspect the file's group owner:
    $ ls -l LOGFILE
If the owner is not `adm`, run the following command to correct this:
    $ sudo chgrp adm LOGFILE
Rationale: | The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_rsyslog_files_groupownership
Identifiers and References | References: BP28(R46), BP28(R5), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001314, 4.3.3.7.3, SR 2.1, SR 5.2, 0988, 1405, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-10.5.1, Req-10.5.2
#### Rule Ensure Log Files Are Owned By Appropriate User [ref]
The owner of all log files written by `rsyslog` should be `adm`. These log files are determined by the second part of each Rule line in `/etc/rsyslog.conf` and typically all appear in `/var/log`. For each log file LOGFILE referenced in `/etc/rsyslog.conf`, run the following command to inspect the file's owner:
    $ ls -l LOGFILE
If the owner is not `adm`, run the following command to correct this:
    $ sudo chown adm LOGFILE
Rationale: | The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_rsyslog_files_ownership
Identifiers and References | References: BP28(R46), BP28(R5), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-001314, 4.3.3.7.3, SR 2.1, SR 5.2, 0988, 1405, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-10.5.1, Req-10.5.2
#### Rule Ensure System Log Files Have Correct Permissions [ref]
The file permissions for all log files written by `rsyslog` should be set to 600, or more restrictive. These log files are determined by the second part of each Rule line in `/etc/rsyslog.conf` and typically all appear in `/var/log`. For each log file LOGFILE referenced in `/etc/rsyslog.conf`, run the following command to inspect the file's permissions:
    $ ls -l LOGFILE
If the permissions are not 600 or more restrictive, run the following command to correct this:
    $ sudo chmod 0600 LOGFILE
"
Rationale: | Log files can contain valuable information regarding system configuration. If the system log files are not protected unauthorized users could change the logged data, eliminating their forensic value.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_rsyslog_files_permissions
Identifiers and References | References: BP28(R36), CCI-001314, 0988, 1405, 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, CM-6(a), AC-6(1), Req-10.5.1, Req-10.5.2
Group Ensure All Logs are Rotated by logrotate Group contains 1 rule
[ref] Edit the file `/etc/logrotate.d/syslog`. Find the first line, which should look like this (wrapped for clarity):
    /var/log/messages /var/log/secure /var/log/maillog /var/log/spooler \
      /var/log/boot.log /var/log/cron {
Edit this line so that it contains a one-space-separated listing of each log file referenced in `/etc/rsyslog.conf`. All logs in use on a system must be rotated regularly, or the log files will consume disk space over time, eventually interfering with system operation. The file `/etc/logrotate.d/syslog` is the configuration file used by the `logrotate` program to maintain all log files written by `syslog`. By default, it rotates logs weekly and stores four archival copies of each log. These settings can be modified by editing `/etc/logrotate.conf`, but the defaults are sufficient for purposes of this guide. Note that `logrotate` is run nightly by the cron job `/etc/cron.daily/logrotate`. If particularly active logs need to be rotated more often than once a day, some other mechanism must be used.
#### Rule Ensure Logrotate Runs Periodically [ref]
The `logrotate` utility allows for the automatic rotation of log files. The frequency of rotation is specified in `/etc/logrotate.conf`, which triggers a cron task. To configure logrotate to run daily, add or correct the following line in `/etc/logrotate.conf`:
    # rotate log files frequency
    daily
Rationale: | Log files that are not properly rotated run the risk of growing so large that they fill up the /var/log partition. Valuable logging information could be lost if the /var/log partition becomes full.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_ensure_logrotate_activated
Identifiers and References | References: BP28(R43), NT12(R18), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-000366, 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, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), PR.PT-1, Req-10.7
Remediation Shell script ⇲
    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    LOGROTATE_CONF_FILE="/etc/logrotate.conf"
    CRON_DAILY_LOGROTATE_FILE="/etc/cron.daily/logrotate"

    # daily rotation is configured
    grep -q "^daily$" $LOGROTATE_CONF_FILE|| echo "daily" >> $LOGROTATE_CONF_FILE

    # remove any line configuring weekly, monthly or yearly rotation
    sed -i '/^\s*\(weekly\|monthly\|yearly\).*$/d' $LOGROTATE_CONF_FILE

    # configure cron.daily if not already
    if ! grep -q "^[[:space:]]*/usr/sbin/logrotate[[:alnum:][:blank:][:punct:]]*$LOGROTATE_CONF_FILE$" $CRON_DAILY_LOGROTATE_FILE; then
    	echo "#!/bin/sh" > $CRON_DAILY_LOGROTATE_FILE
    	echo "/usr/sbin/logrotate $LOGROTATE_CONF_FILE" >> $CRON_DAILY_LOGROTATE_FILE
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Configure daily log rotation in /etc/logrotate.conf
      lineinfile:
        create: true
        dest: /etc/logrotate.conf
        regexp: ^daily$
        line: daily
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-10.7
        - configure_strategy
        - ensure_logrotate_activated
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Make sure daily log rotation setting is not overriden in /etc/logrotate.conf
      lineinfile:
        create: false
        dest: /etc/logrotate.conf
        regexp: ^[\s]*(weekly|monthly|yearly)$
        state: absent
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-10.7
        - configure_strategy
        - ensure_logrotate_activated
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Configure cron.daily if not already
      block:

        - name: Add shebang
          lineinfile:
            path: /etc/cron.daily/logrotate
            line: '#!/bin/sh'
            insertbefore: BOF
            create: true

        - name: Add logrotate call
          lineinfile:
            path: /etc/cron.daily/logrotate
            line: /usr/sbin/logrotate /etc/logrotate.conf
            regexp: ^[\s]*/usr/sbin/logrotate[\s\S]*/etc/logrotate.conf$
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-10.7
        - configure_strategy
        - ensure_logrotate_activated
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
Group Configure rsyslogd to Accept Remote Messages If Acting as a Log Server Group contains 2 rules
[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 syslog-ng is Installed [ref]
syslog-ng can be installed in replacement of rsyslog. The `syslog-ng-core` package can be installed with the following command:
    $ apt-get install syslog-ng-core
Rationale: | The syslog-ng-core package provides the syslog-ng daemon, which provides system logging services.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_syslogng_installed
Identifiers and References | References: BP28(R46), BP28(R5), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-001311, CCI-001312, 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, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), PR.PT-1
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    - name: Ensure syslog-ng is installed
      package:
        name: syslog-ng
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-CM-6(a)
        - enable_strategy
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - package_syslogng_installed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    include install_syslog-ng

    class install_syslog-ng {
      package { 'syslog-ng':
        ensure => 'installed',
      }
    }
Remediation script ⇲
    [[packages]]
    name = "syslog-ng"
    version = "*"
#### Rule Enable syslog-ng Service [ref]
The `syslog-ng` service (in replacement of rsyslog) provides syslog-style logging by default on Debian. The `syslog-ng` service can be enabled with the following command:
    $ sudo systemctl enable syslog-ng.service
Rationale: | The `syslog-ng` 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_syslogng_enabled
Identifiers and References | References: BP28(R46), BP28(R5), 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, 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, CCI-001311, CCI-001312, CCI-001557, CCI-001851, 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, 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, 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, CM-6(a), AU-4(1), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.DS-4, PR.PT-1
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    - name: Enable service syslog-ng
      block:

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

        - name: Enable service syslog-ng
          service:
            name: syslog-ng
            enabled: 'yes'
            state: started
            masked: 'no'
          when:
            - '"syslog-ng" in ansible_facts.packages'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AU-4(1)
        - NIST-800-53-CM-6(a)
        - enable_strategy
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - service_syslogng_enabled
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    include enable_syslog-ng

    class enable_syslog-ng {
      service {'syslog-ng':
        enable => true,
        ensure => 'running',
      }
    }
Remediation script ⇲
    [customizations.services]
    enabled = ["syslog-ng"]
#### 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
Identifiers and References | References: BP28(R5), NT28(R46), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-001311, CCI-001312, CCI-000366, 164.312(a)(2)(ii), 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, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), PR.PT-1, FTP_ITC_EXT.1.1, SRG-OS-000479-GPOS-00224, SRG-OS-000051-GPOS-00024, SRG-OS-000480-GPOS-00227
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    - name: Ensure rsyslog is installed
      package:
        name: rsyslog
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-CM-6(a)
        - enable_strategy
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - package_rsyslog_installed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    include install_rsyslog

    class install_rsyslog {
      package { 'rsyslog':
        ensure => 'installed',
      }
    }
Remediation script ⇲
    [[packages]]
    name = "rsyslog"
    version = "*"
#### Rule Enable rsyslog Service [ref]
The `rsyslog` service provides syslog-style logging by default on Debian 11. 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
Identifiers and References | References: BP28(R5), NT28(R46), 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, 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, CCI-001311, CCI-001312, CCI-001557, CCI-001851, CCI-000366, 164.312(a)(2)(ii), 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, 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, 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, CM-6(a), AU-4(1), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.DS-4, PR.PT-1, SRG-OS-000480-GPOS-00227
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    - name: Enable service rsyslog
      block:

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

        - name: Enable service rsyslog
          service:
            name: rsyslog
            enabled: 'yes'
            state: started
            masked: 'no'
          when:
            - '"rsyslog" in ansible_facts.packages'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AU-4(1)
        - NIST-800-53-CM-6(a)
        - enable_strategy
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - service_rsyslog_enabled
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    include enable_rsyslog

    class enable_rsyslog {
      service {'rsyslog':
        enable => true,
        ensure => 'running',
      }
    }
Remediation script ⇲
    [customizations.services]
    enabled = ["rsyslog"]
Group File Permissions and Masks Group contains 5 groups and 17 rules
[ref] Traditional Unix security relies heavily on file and directory permissions to prevent unauthorized users from reading or modifying files to which they should not have access. Several of the commands in this section search filesystems for files or directories with certain characteristics, and are intended to be run on every local partition on a given system. When the variable PART appears in one of the commands below, it means that the command is intended to be run repeatedly, with the name of each local partition substituted for PART in turn. The following command prints a list of all xfs partitions on the local system, which is the default filesystem for Debian 11 installations:
    $ mount -t xfs | awk '{print $3}'
For any systems that use a different local filesystem type, modify this command as appropriate.
Group Verify Permissions on Important Files and Directories Group contains 1 group and 15 rules
[ref] Permissions for many files on a system must be set restrictively to ensure sensitive information is properly protected. This section discusses important permission restrictions which can be verified to ensure that no harmful discrepancies have arisen.
Group Verify Permissions on Files with Local Account Information and Credentials Group contains 12 rules
[ref] The default restrictive permissions for files which act as important security databases such as `passwd`, `shadow`, `group`, and `gshadow` files must be maintained. Many utilities need read access to the `passwd` file in order to function properly, but read access to the `shadow` file allows malicious attacks against system passwords, and should never be enabled.
#### Rule Verify Group Who Owns group File [ref]
To properly set the group owner of `/etc/group`, run the command:
    $ sudo chgrp root /etc/group
Rationale: | The `/etc/group` file contains information regarding groups that are configured on the system. Protection of this file is important for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_groupowner_etc_group
Identifiers and References | References: 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chgrp 0 /etc/group
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/group
      stat:
        path: /etc/group
      register: file_exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_groupowner_etc_group
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure group owner 0 on /etc/group
      file:
        path: /etc/group
        group: '0'
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_groupowner_etc_group
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify Group Who Owns gshadow File [ref]
To properly set the group owner of `/etc/gshadow`, run the command:
    $ sudo chgrp shadow /etc/gshadow
Rationale: | The `/etc/gshadow` file contains group password hashes. Protection of this file is critical for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_groupowner_etc_gshadow
Identifiers and References | References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chgrp 42 /etc/gshadow
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/gshadow
      stat:
        path: /etc/gshadow
      register: file_exists
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - configure_strategy
        - file_groupowner_etc_gshadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure group owner 42 on /etc/gshadow
      file:
        path: /etc/gshadow
        group: '42'
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - configure_strategy
        - file_groupowner_etc_gshadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify Group Who Owns passwd File [ref]
To properly set the group owner of `/etc/passwd`, run the command:
    $ sudo chgrp root /etc/passwd
Rationale: | The `/etc/passwd` file contains information about the users that are configured on the system. Protection of this file is critical for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_groupowner_etc_passwd
Identifiers and References | References: 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chgrp 0 /etc/passwd
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/passwd
      stat:
        path: /etc/passwd
      register: file_exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_groupowner_etc_passwd
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure group owner 0 on /etc/passwd
      file:
        path: /etc/passwd
        group: '0'
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_groupowner_etc_passwd
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify Group Who Owns shadow File [ref]
To properly set the group owner of `/etc/shadow`, run the command:
    $ sudo chgrp shadow /etc/shadow
Rationale: | The `/etc/shadow` file stores password hashes. Protection of this file is critical for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_groupowner_etc_shadow
Identifiers and References | References: 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chgrp 42 /etc/shadow
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/shadow
      stat:
        path: /etc/shadow
      register: file_exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_groupowner_etc_shadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure group owner 42 on /etc/shadow
      file:
        path: /etc/shadow
        group: '42'
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_groupowner_etc_shadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify User Who Owns group File [ref]
To properly set the owner of `/etc/group`, run the command:
    $ sudo chown root /etc/group
Rationale: | The `/etc/group` file contains information regarding groups that are configured on the system. Protection of this file is important for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_owner_etc_group
Identifiers and References | References: 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chown 0 /etc/group
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/group
      stat:
        path: /etc/group
      register: file_exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_owner_etc_group
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure owner 0 on /etc/group
      file:
        path: /etc/group
        owner: '0'
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_owner_etc_group
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify User Who Owns gshadow File [ref]
To properly set the owner of `/etc/gshadow`, run the command:
    $ sudo chown root /etc/gshadow
Rationale: | The `/etc/gshadow` file contains group password hashes. Protection of this file is critical for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_owner_etc_gshadow
Identifiers and References | References: BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chown 0 /etc/gshadow
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/gshadow
      stat:
        path: /etc/gshadow
      register: file_exists
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - configure_strategy
        - file_owner_etc_gshadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure owner 0 on /etc/gshadow
      file:
        path: /etc/gshadow
        owner: '0'
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - configure_strategy
        - file_owner_etc_gshadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify User Who Owns passwd File [ref]
To properly set the owner of `/etc/passwd`, run the command:
    $ sudo chown root /etc/passwd
Rationale: | The `/etc/passwd` file contains information about the users that are configured on the system. Protection of this file is critical for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_owner_etc_passwd
Identifiers and References | References: 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chown 0 /etc/passwd
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/passwd
      stat:
        path: /etc/passwd
      register: file_exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_owner_etc_passwd
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure owner 0 on /etc/passwd
      file:
        path: /etc/passwd
        owner: '0'
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_owner_etc_passwd
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify User Who Owns shadow File [ref]
To properly set the owner of `/etc/shadow`, run the command:
    $ sudo chown root /etc/shadow
Rationale: | The `/etc/shadow` file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_owner_etc_shadow
Identifiers and References | References: BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chown 0 /etc/shadow
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/shadow
      stat:
        path: /etc/shadow
      register: file_exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_owner_etc_shadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure owner 0 on /etc/shadow
      file:
        path: /etc/shadow
        owner: '0'
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_owner_etc_shadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify Permissions on group File [ref]
To properly set the permissions of `/etc/passwd`, run the command:
    $ sudo chmod 0644 /etc/passwd
Rationale: | The `/etc/group` file contains information regarding groups that are configured on the system. Protection of this file is important for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_etc_group
Identifiers and References | References: BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chmod u-xs,g-xws,o-xwt /etc/group
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/group
      stat:
        path: /etc/group
      register: file_exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_permissions_etc_group
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure permission u-xs,g-xws,o-xwt on /etc/group
      file:
        path: /etc/group
        mode: u-xs,g-xws,o-xwt
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_permissions_etc_group
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify Permissions on gshadow File [ref]
To properly set the permissions of `/etc/gshadow`, run the command:
    $ sudo chmod 0640 /etc/gshadow
Rationale: | The `/etc/gshadow` file contains group password hashes. Protection of this file is critical for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_etc_gshadow
Identifiers and References | References: BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chmod u-xs,g-xws,o-xwrt /etc/gshadow
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/gshadow
      stat:
        path: /etc/gshadow
      register: file_exists
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - configure_strategy
        - file_permissions_etc_gshadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure permission u-xs,g-xws,o-xwrt on /etc/gshadow
      file:
        path: /etc/gshadow
        mode: u-xs,g-xws,o-xwrt
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - configure_strategy
        - file_permissions_etc_gshadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify Permissions on passwd File [ref]
To properly set the permissions of `/etc/passwd`, run the command:
    $ sudo chmod 0644 /etc/passwd
Rationale: | If the `/etc/passwd` file is writable by a group-owner or the world the risk of its compromise is increased. The file contains the list of accounts on the system and associated information, and protection of this file is critical for system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_etc_passwd
Identifiers and References | References: BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chmod u-xs,g-xws,o-xwt /etc/passwd
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/passwd
      stat:
        path: /etc/passwd
      register: file_exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_permissions_etc_passwd
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure permission u-xs,g-xws,o-xwt on /etc/passwd
      file:
        path: /etc/passwd
        mode: u-xs,g-xws,o-xwt
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_permissions_etc_passwd
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify Permissions on shadow File [ref]
To properly set the permissions of `/etc/shadow`, run the command:
    $ sudo chmod 0640 /etc/shadow
Rationale: | The `/etc/shadow` file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_etc_shadow
Identifiers and References | References: BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 4.3.3.7.3, SR 2.1, SR 5.2, 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, 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, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-8.7.c
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    chmod u-xs,g-xws,o-xwrt /etc/shadow
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | configure
    - name: Test for existence /etc/shadow
      stat:
        path: /etc/shadow
      register: file_exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_permissions_etc_shadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed

    - name: Ensure permission u-xs,g-xws,o-xwrt on /etc/shadow
      file:
        path: /etc/shadow
        mode: u-xs,g-xws,o-xwrt
      when: file_exists.stat is defined and file_exists.stat.exists
      tags:
        - CJIS-5.5.2.2
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-8.7.c
        - configure_strategy
        - file_permissions_etc_shadow
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
#### Rule Verify that local System.map file (if exists) is readable only by root [ref]
Files containing sensitive informations should be protected by restrictive permissions. Most of the time, there is no need that these files need to be read by any non-root user To properly set the permissions of `/boot/System.map-*`, run the command:
    $ sudo chmod 0600 /boot/System.map-*
Rationale: | The `System.map` file contains information about kernel symbols and can give some hints to generate local exploitation.
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_systemmap
Identifiers and References | References: BP28(R13)
#### Rule Enable Kernel Parameter to Enforce DAC on Hardlinks [ref]
To set the runtime status of the `fs.protected_hardlinks` kernel parameter, run the following command:
    $ sudo sysctl -w fs.protected_hardlinks=1
To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:
    fs.protected_hardlinks = 1
Rationale: | By enabling this kernel parameter, users can no longer create soft or hard links to files which they do not own. Disallowing such hardlinks mitigate vulnerabilities based on insecure file system accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of `open()` or `creat()`.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_fs_protected_hardlinks
Identifiers and References | References: BP28(R23), CCI-002165, 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, CM-6(a), AC-6(1), SRG-OS-000324-GPOS-00125
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable
    - name: List /etc/sysctl.d/*.conf files
      find:
        paths: /etc/sysctl.d/
        contains: ^[\s]*fs.protected_hardlinks.*$
        patterns: '*.conf'
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_fs_protected_hardlinks

    - name: Comment out any occurrences of fs.protected_hardlinks from /etc/sysctl.d/*.conf
        files
      replace:
        path: '{{ item }}'
        regexp: ^[\s]*fs.protected_hardlinks
        replace: '#fs.protected_hardlinks'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_fs_protected_hardlinks

    - name: Ensure sysctl fs.protected_hardlinks is set to 1
      sysctl:
        name: fs.protected_hardlinks
        value: '1'
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_fs_protected_hardlinks
#### Rule Enable Kernel Parameter to Enforce DAC on Symlinks [ref]
To set the runtime status of the `fs.protected_symlinks` kernel parameter, run the following command:
    $ sudo sysctl -w fs.protected_symlinks=1
To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:
    fs.protected_symlinks = 1
Rationale: | By enabling this kernel parameter, symbolic links are permitted to be followed only when outside a sticky world-writable directory, or when the UID of the link and follower match, or when the directory owner matches the symlink's owner. Disallowing such symlinks helps mitigate vulnerabilities based on insecure file system accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of `open()` or `creat()`.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_fs_protected_symlinks
Identifiers and References | References: BP28(R23), CCI-002165, 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, CM-6(a), AC-6(1), SRG-OS-000324-GPOS-00125
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable
    - name: List /etc/sysctl.d/*.conf files
      find:
        paths: /etc/sysctl.d/
        contains: ^[\s]*fs.protected_symlinks.*$
        patterns: '*.conf'
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_fs_protected_symlinks

    - name: Comment out any occurrences of fs.protected_symlinks from /etc/sysctl.d/*.conf
        files
      replace:
        path: '{{ item }}'
        regexp: ^[\s]*fs.protected_symlinks
        replace: '#fs.protected_symlinks'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_fs_protected_symlinks

    - name: Ensure sysctl fs.protected_symlinks is set to 1
      sysctl:
        name: fs.protected_symlinks
        value: '1'
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AC-6(1)
        - NIST-800-53-CM-6(a)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_fs_protected_symlinks
Group Restrict Programs from Dangerous Execution Patterns Group contains 2 groups and 2 rules
[ref] The recommendations in this section are designed to ensure that the system's features to protect against potentially dangerous program execution are activated. These protections are applied at the system initialization or kernel level, and defend against certain types of badly-configured or compromised programs.
Group Disable Core Dumps Group contains 1 rule
[ref] A core dump file is the memory image of an executable program when it was terminated by the operating system due to errant behavior. In most cases, only software developers legitimately need to access these files. The core dump files may also contain sensitive information, or unnecessarily occupy large amounts of disk space. Once a hard limit is set in `/etc/security/limits.conf`, or to a file within the `/etc/security/limits.d/` directory, a user cannot increase that limit within his or her own session. If access to core dumps is required, consider restricting them to only certain users or groups. See the `limits.conf` man page for more information. The core dumps of setuid programs are further protected. The `sysctl` variable `fs.suid_dumpable` controls whether the kernel allows core dumps from these programs at all. The default value of 0 is recommended.
#### Rule Disable Core Dumps for SUID programs [ref]
To set the runtime status of the `fs.suid_dumpable` kernel parameter, run the following command:
    $ sudo sysctl -w fs.suid_dumpable=0
To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:
    fs.suid_dumpable = 0
Rationale: | The core dump of a setuid program is more likely to contain sensitive data, as the program itself runs with greater privileges than the user who initiated execution of the program. Disabling the ability for any setuid program to write a core file decreases the risk of unauthorized access of such data.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_fs_suid_dumpable
Identifiers and References | References: BP28(R23), 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SI-11(a), SI-11(b)
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable
    - name: List /etc/sysctl.d/*.conf files
      find:
        paths: /etc/sysctl.d/
        contains: ^[\s]*fs.suid_dumpable.*$
        patterns: '*.conf'
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-SI-11(a)
        - NIST-800-53-SI-11(b)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_fs_suid_dumpable

    - name: Comment out any occurrences of fs.suid_dumpable from /etc/sysctl.d/*.conf
        files
      replace:
        path: '{{ item }}'
        regexp: ^[\s]*fs.suid_dumpable
        replace: '#fs.suid_dumpable'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-SI-11(a)
        - NIST-800-53-SI-11(b)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_fs_suid_dumpable

    - name: Ensure sysctl fs.suid_dumpable is set to 0
      sysctl:
        name: fs.suid_dumpable
        value: '0'
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-SI-11(a)
        - NIST-800-53-SI-11(b)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_fs_suid_dumpable
Group Enable ExecShield Group contains 1 rule
[ref] ExecShield describes kernel features that provide protection against exploitation of memory corruption errors such as buffer overflows. These features include random placement of the stack and other memory regions, prevention of execution in memory that should only hold data, and special handling of text buffers. These protections are enabled by default on 32-bit systems and controlled through `sysctl` variables `kernel.exec-shield` and `kernel.randomize_va_space`. On the latest 64-bit systems, `kernel.exec-shield` cannot be enabled or disabled with `sysctl`.
#### Rule Enable Randomized Layout of Virtual Address Space [ref]
To set the runtime status of the `kernel.randomize_va_space` kernel parameter, run the following command:
    $ sudo sysctl -w kernel.randomize_va_space=2
To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:
    kernel.randomize_va_space = 2
Rationale: | Address space layout randomization (ASLR) makes it more difficult for an attacker to predict the location of attack code they have introduced into a process's address space during an attempt at exploitation. Additionally, ASLR makes it more difficult for an attacker to know the location of existing code in order to re-purpose it using return oriented programming (ROP) techniques.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_kernel_randomize_va_space
Identifiers and References | References: BP28(R23), 3.1.7, CCI-000366, CCI-002824, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), CIP-002-5 R1.1, CIP-002-5 R1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 4.1, CIP-004-6 4.2, CIP-004-6 R2.2.3, CIP-004-6 R2.2.4, CIP-004-6 R2.3, CIP-004-6 R4, CIP-005-6 R1, CIP-005-6 R1.1, CIP-005-6 R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-6 R.1.1, CIP-009-6 R4, SC-30, SC-30(2), CM-6(a), SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable
    - name: List /etc/sysctl.d/*.conf files
      find:
        paths: /etc/sysctl.d/
        contains: ^[\s]*kernel.randomize_va_space.*$
        patterns: '*.conf'
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-171-3.1.7
        - NIST-800-53-CM-6(a)
        - NIST-800-53-SC-30
        - NIST-800-53-SC-30(2)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_kernel_randomize_va_space

    - name: Comment out any occurrences of kernel.randomize_va_space from /etc/sysctl.d/*.conf
        files
      replace:
        path: '{{ item }}'
        regexp: ^[\s]*kernel.randomize_va_space
        replace: '#kernel.randomize_va_space'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-171-3.1.7
        - NIST-800-53-CM-6(a)
        - NIST-800-53-SC-30
        - NIST-800-53-SC-30(2)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_kernel_randomize_va_space

    - name: Ensure sysctl kernel.randomize_va_space is set to 2
      sysctl:
        name: kernel.randomize_va_space
        value: '2'
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-171-3.1.7
        - NIST-800-53-CM-6(a)
        - NIST-800-53-SC-30
        - NIST-800-53-SC-30(2)
        - disable_strategy
        - low_complexity
        - medium_disruption
        - medium_severity
        - reboot_required
        - sysctl_kernel_randomize_va_space
Group Services Group contains 6 groups and 15 rules
[ref] The best protection against vulnerable software is running less software. This section describes how to review the software which Debian 11 installs on a system and disable software which is not needed. It then enumerates the software packages installed on a default Debian 11 system and provides guidance about which ones can be safely disabled. Debian 11 provides a convenient minimal install option that essentially installs the bare necessities for a functional system. When building Debian 11 systems, it is highly recommended to select the minimal packages and then build up the system from there.
Group APT service configuration Group contains 2 rules
[ref] The apt service manage the package management and update of the whole system. Its configuration need to be properly defined to ensure efficient security updates, packages and repository authentication and proper lifecycle management.
#### Rule Disable unauthenticated repositories in APT configuration [ref]
Unauthenticated repositories should not be used for updates.
Rationale: | Repositories hosts all packages that will be intsalled on the system during update. If a repository is not authenticated, the associated packages can't be trusted, and then should not be installed localy.
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_apt_conf_disallow_unauthenticated
Identifiers and References | References: BP28(R15)
#### Rule Ensure that official distribution repositories are used [ref]
Check that official Debian repositories, including security repository, are configured in apt.
Rationale: | The Debian distribution deliver DSA (Debian Security Announce), through the official Debian security repository, to correct various vulnerabilities impacting the Debian packages. Using the official repositories is the best way to ensure that the Debian updates are integrated soon enough.
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_apt_sources_list_official
Identifiers and References | References: BP28(R15)
Group Cron and At Daemons Group contains 1 rule
[ref] The cron and at services are used to allow commands to be executed at a later time. The cron service is required by almost all systems to perform necessary maintenance tasks, while at may or may not be required on a given system. Both daemons should be configured defensively.
#### Rule Install the cron service [ref]
The Cron service should be installed.
Rationale: | The cron service allow periodic job execution, needed for almost all administrative tasks and services (software update, log rotating, etc.). Access to cron service should be restricted to administrative accounts only.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_cron_installed
Identifiers and References | References: BP28(R50), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 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, 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, 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, CM-6(a), PR.IP-1, PR.PT-3
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    - name: Ensure cron is installed
      package:
        name: cron
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-CM-6(a)
        - enable_strategy
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - package_cron_installed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    include install_cron

    class install_cron {
      package { 'cron':
        ensure => 'installed',
      }
    }
Remediation script ⇲
    [[packages]]
    name = "cron"
    version = "*"
Group Deprecated services Group contains 5 rules
[ref] Some deprecated software services impact the overall system security due to their behavior (leak of confidentiality in network exchange, usage as uncontrolled communication channel, risk associated with the service due to its old age, etc.
#### Rule Uninstall the inet-based telnet server [ref]
The inet-based telnet daemon should be uninstalled.
Rationale: | `telnet` allows clear text communications, and does not protect any data transmission between client and server. Any confidential data can be listened and no integrity checking is made.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_package_inetutils-telnetd_removed
Identifiers and References | References: NT007(R03), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 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, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    # CAUTION: This remediation script will remove inetutils-telnetd
    #	   from the system, and may remove any packages
    #	   that depend on inetutils-telnetd. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    DEBIAN_FRONTEND=noninteractive apt-get remove -y "inetutils-telnetd"
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    - name: Ensure inetutils-telnetd is removed
      package:
        name: inetutils-telnetd
        state: absent
      tags:
        - NIST-800-53-CM-6(a)
        - NIST-800-53-CM-7(a)
        - NIST-800-53-CM-7(b)
        - disable_strategy
        - high_severity
        - low_complexity
        - low_disruption
        - no_reboot_needed
        - package_inetutils-telnetd_removed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    include remove_inetutils-telnetd

    class remove_inetutils-telnetd {
      package { 'inetutils-telnetd':
        ensure => 'purged',
      }
    }
#### Rule Uninstall the nis package [ref]
The support for Yellowpages should not be installed unless it is required.
Rationale: | NIS is the historical SUN service for central account management, more and more replaced by LDAP. NIS does not support efficiently security constraints, ACL, etc. and should not be used.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_package_nis_removed
Identifiers and References |
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    # CAUTION: This remediation script will remove nis
    #	   from the system, and may remove any packages
    #	   that depend on nis. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    DEBIAN_FRONTEND=noninteractive apt-get remove -y "nis"
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    - name: Ensure nis is removed
      package:
        name: nis
        state: absent
      tags:
        - disable_strategy
        - low_complexity
        - low_disruption
        - low_severity
        - no_reboot_needed
        - package_nis_removed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    include remove_nis

    class remove_nis {
      package { 'nis':
        ensure => 'purged',
      }
    }
#### Rule Uninstall the ntpdate package [ref]
ntpdate is a historical ntp synchronization client for unixes. It sould be uninstalled.
Rationale: | ntpdate is an old not security-compliant ntp client. It should be replaced by modern ntp clients such as ntpd, able to use cryptographic mechanisms integrated in NTP.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_package_ntpdate_removed
Identifiers and References |
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    # CAUTION: This remediation script will remove ntpdate
    #	   from the system, and may remove any packages
    #	   that depend on ntpdate. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    DEBIAN_FRONTEND=noninteractive apt-get remove -y "ntpdate"
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    - name: Ensure ntpdate is removed
      package:
        name: ntpdate
        state: absent
      tags:
        - disable_strategy
        - low_complexity
        - low_disruption
        - low_severity
        - no_reboot_needed
        - package_ntpdate_removed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    include remove_ntpdate

    class remove_ntpdate {
      package { 'ntpdate':
        ensure => 'purged',
      }
    }
#### Rule Uninstall the ssl compliant telnet server [ref]
The `telnet` daemon, even with ssl support, should be uninstalled.
Rationale: | `telnet`, even with ssl support, should not be installed. When remote shell is required, up-to-date ssh daemon can be used.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_package_telnetd-ssl_removed
Identifiers and References | References: NT007(R02), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 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, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    # CAUTION: This remediation script will remove telnetd-ssl
    #	   from the system, and may remove any packages
    #	   that depend on telnetd-ssl. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    DEBIAN_FRONTEND=noninteractive apt-get remove -y "telnetd-ssl"
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    - name: Ensure telnetd-ssl is removed
      package:
        name: telnetd-ssl
        state: absent
      tags:
        - NIST-800-53-CM-6(a)
        - NIST-800-53-CM-7(a)
        - NIST-800-53-CM-7(b)
        - disable_strategy
        - high_severity
        - low_complexity
        - low_disruption
        - no_reboot_needed
        - package_telnetd-ssl_removed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    include remove_telnetd-ssl

    class remove_telnetd-ssl {
      package { 'telnetd-ssl':
        ensure => 'purged',
      }
    }
#### Rule Uninstall the telnet server [ref]
The telnet daemon should be uninstalled.
Rationale: | `telnet` allows clear text communications, and does not protect any data transmission between client and server. Any confidential data can be listened and no integrity checking is made.'
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_package_telnetd_removed
Identifiers and References | References: BP28(R1), NT007(R03), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 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, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    # CAUTION: This remediation script will remove telnetd
    #	   from the system, and may remove any packages
    #	   that depend on telnetd. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    DEBIAN_FRONTEND=noninteractive apt-get remove -y "telnetd"
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    - name: Ensure telnetd is removed
      package:
        name: telnetd
        state: absent
      tags:
        - NIST-800-53-CM-6(a)
        - NIST-800-53-CM-7(a)
        - NIST-800-53-CM-7(b)
        - disable_strategy
        - high_severity
        - low_complexity
        - low_disruption
        - no_reboot_needed
        - package_telnetd_removed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | disable
    include remove_telnetd

    class remove_telnetd {
      package { 'telnetd':
        ensure => 'purged',
      }
    }
Group Network Time Protocol Group contains 2 rules
[ref] The Network Time Protocol is used to manage the system clock over a network. Computer clocks are not very accurate, so time will drift unpredictably on unmanaged systems. Central time protocols can be used both to ensure that time is consistent among a network of systems, and that their time is consistent with the outside world. If every system on a network reliably reports the same time, then it is much easier to correlate log messages in case of an attack. In addition, a number of cryptographic protocols (such as Kerberos) use timestamps to prevent certain types of attacks. If your network does not have synchronized time, these protocols may be unreliable or even unusable. Depending on the specifics of the network, global time accuracy may be just as important as local synchronization, or not very important at all. If your network is connected to the Internet, using a public timeserver (or one provided by your enterprise) provides globally accurate timestamps which may be essential in investigating or responding to an attack which originated outside of your network. A typical network setup involves a small number of internal systems operating as NTP servers, and the remainder obtaining time information from those internal servers. There is a choice between the daemons `ntpd` and `chronyd`, which are available from the repositories in the `ntp` and `chrony` packages respectively. The default `chronyd` daemon can work well when external time references are only intermittently accesible, can perform well even when the network is congested for longer periods of time, can usually synchronize the clock faster and with better time accuracy, and quickly adapts to sudden changes in the rate of the clock, for example, due to changes in the temperature of the crystal oscillator. `Chronyd` should be considered for all systems which are frequently suspended or otherwise intermittently disconnected and reconnected to a network. Mobile and virtual systems for example. The `ntpd` NTP daemon fully supports NTP protocol version 4 (RFC 5905), including broadcast, multicast, manycast clients and servers, and the orphan mode. It also supports extra authentication schemes based on public-key cryptography (RFC 5906). The NTP daemon (`ntpd`) should be considered for systems which are normally kept permanently on. Systems which are required to use broadcast or multicast IP, or to perform authentication of packets with the `Autokey` protocol, should consider using `ntpd`. Refer to https://wiki.debian.org/NTP for more detailed comparison of features of `chronyd` and `ntpd` daemon features respectively, and for further guidance how to choose between the two NTP daemons. The upstream manual pages at http://chrony.tuxfamily.org/manual.html for `chronyd` and http://www.ntp.org for `ntpd` provide additional information on the capabilities and configuration of each of the NTP daemons.
#### Rule Install the ntp service [ref]
The ntpd service should be installed.
Rationale: | Time synchronization (using NTP) is required by almost all network and administrative tasks (syslog, cryptographic based services (authentication, etc.), etc.). Ntpd is regulary maintained and updated, supporting security features such as RFC 5906.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_package_ntp_installed
Identifiers and References | References: NT012(R03), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-000160, 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, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), PR.PT-1, Req-10.4
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    - name: Ensure ntp is installed
      package:
        name: ntp
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-10.4
        - enable_strategy
        - high_severity
        - low_complexity
        - low_disruption
        - no_reboot_needed
        - package_ntp_installed
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    include install_ntp

    class install_ntp {
      package { 'ntp':
        ensure => 'installed',
      }
    }
Remediation script ⇲
    [[packages]]
    name = "ntp"
    version = "*"
#### Rule Enable the NTP Daemon [ref]
The `ntpd` service can be enabled with the following command:
    $ sudo systemctl enable ntpd.service
Rationale: | Enabling the `ntpd` service ensures that the `ntpd` service will be running and that the system will synchronize its time to any servers specified. This is important whether the system is configured to be a client (and synchronize only its own clock) or it is also acting as an NTP server to other systems. Synchronizing time is essential for authentication services such as Kerberos, but it is also important for maintaining accurate logs and auditing possible security breaches. The NTP daemon offers all of the functionality of `ntpdate`, which is now deprecated.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_service_ntp_enabled
Identifiers and References | References: NT012(R03), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, CCI-000160, 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, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), AU-8(1)(a), PR.PT-1, Req-10.4
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    - name: Enable service ntp
      block:

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

        - name: Enable service ntp
          service:
            name: ntp
            enabled: 'yes'
            state: started
            masked: 'no'
          when:
            - '"ntp" in ansible_facts.packages'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - NIST-800-53-AU-8(1)(a)
        - NIST-800-53-CM-6(a)
        - PCI-DSS-Req-10.4
        - enable_strategy
        - high_severity
        - low_complexity
        - low_disruption
        - no_reboot_needed
        - service_ntp_enabled
Remediation Puppet snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | enable
    include enable_ntp

    class enable_ntp {
      service {'ntp':
        enable => true,
        ensure => 'running',
      }
    }
Remediation script ⇲
    [customizations.services]
    enabled = ["ntp"]
Group SSH Server Group contains 1 group and 5 rules
[ref] The SSH protocol is recommended for remote login and remote file transfer. SSH provides confidentiality and integrity for data exchanged between two systems, as well as server authentication, through the use of public key cryptography. The implementation included with the system is called OpenSSH, and more detailed documentation is available from its website, https://www.openssh.com. Its server program is called `sshd` and provided by the RPM package `openssh-server`.
Group Configure OpenSSH Server if Necessary Group contains 5 rules
[ref] If the system needs to act as an SSH server, then certain changes should be made to the OpenSSH daemon configuration file `/etc/ssh/sshd_config`. The following recommendations can be applied to this file. See the `sshd_config(5)` man page for more detailed information.
#### Rule Set SSH Client Alive Count Max to zero [ref]
The SSH server sends at most `ClientAliveCountMax` messages during a SSH session and waits for a response from the SSH client. The option `ClientAliveInterval` configures timeout after each `ClientAliveCountMax` message. If the SSH server does not receive a response from the client, then the connection is considered idle and terminated. To ensure the SSH idle timeout occurs precisely when the `ClientAliveInterval` is set, set the `ClientAliveCountMax` to value of `0` in `/etc/ssh/sshd_config`:
Rationale: | This ensures a user login will be terminated as soon as the `ClientAliveInterval` is reached.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_set_keepalive_0
Identifiers and References | References: 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, 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, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, 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, AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000480-VMM-002000
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*ClientAliveCountMax\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert before the line matching the regex '^Match'.
    line_number="$(LC_ALL=C grep -n "^Match" "/etc/ssh/sshd_config.bak" | LC_ALL=C sed 's/:.*//g')"
    if [ -z "$line_number" ]; then
        # There was no match of '^Match', insert at
        # the end of the file.
        printf '%s\n' "ClientAliveCountMax 0" >> "/etc/ssh/sshd_config"
    else
        head -n "$(( line_number - 1 ))" "/etc/ssh/sshd_config.bak" > "/etc/ssh/sshd_config"
        printf '%s\n' "ClientAliveCountMax 0" >> "/etc/ssh/sshd_config"
        tail -n "+$(( line_number ))" "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    fi
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    - name: Set SSH Client Alive Count Max to zero
      block:

        - name: Check for duplicate values
          lineinfile:
            path: /etc/ssh/sshd_config
            create: false
            regexp: (?i)^\s*ClientAliveCountMax\s+
            state: absent
          check_mode: true
          changed_when: false
          register: dupes

        - name: Deduplicate values from /etc/ssh/sshd_config
          lineinfile:
            path: /etc/ssh/sshd_config
            create: false
            regexp: (?i)^\s*ClientAliveCountMax\s+
            state: absent
          when: dupes.found is defined and dupes.found > 1

        - name: Insert correct line to /etc/ssh/sshd_config
          lineinfile:
            path: /etc/ssh/sshd_config
            create: true
            regexp: (?i)^\s*ClientAliveCountMax\s+
            line: ClientAliveCountMax 0
            state: present
            insertbefore: ^[#\s]*Match
            validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - CJIS-5.5.6
        - NIST-800-171-3.1.11
        - NIST-800-53-AC-12
        - NIST-800-53-AC-17(a)
        - NIST-800-53-AC-2(5)
        - NIST-800-53-CM-6(a)
        - NIST-800-53-SC-10
        - PCI-DSS-Req-8.1.8
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - restrict_strategy
        - sshd_set_keepalive_0
#### Rule Set SSH Idle Timeout Interval [ref]
SSH allows administrators to set an idle timeout interval. After this interval has passed, the idle user will be automatically logged out. To set an idle timeout interval, edit the following line in `/etc/ssh/sshd_config` as follows:
    ClientAliveInterval 300
The timeout interval is given in seconds. For example, have a timeout of 10 minutes, set interval to 600. If a shorter timeout has already been set for the login shell, that value will preempt any SSH setting made in `/etc/ssh/sshd_config`. Keep in mind that some processes may stop SSH from correctly detecting that the user is idle. Warning: SSH disconnecting idle clients will not have desired effect without also configuring ClientAliveCountMax in the SSH service configuration. Warning: Following conditions may prevent the SSH session to time out: Remote processes on the remote machine generates output. As the output has to be transferred over the network to the client, the timeout is reset every time such transfer happens. Any `scp` or `sftp` activity by the same user to the host resets the timeout.
Rationale: | Terminating an idle ssh session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been let unattended.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_set_idle_timeout
Identifiers and References | References: BP28(R29), 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, 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, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, 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, CM-6(a), AC-17(a), AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000395-GPOS-00175, SRG-OS-000480-VMM-002000
Remediation Shell script ⇲
    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    sshd_idle_timeout_value='300'

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*ClientAliveInterval\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

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

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi
#### Rule Allow Only SSH Protocol 2 [ref]
Only SSH protocol version 2 connections should be permitted. The default setting in `/etc/ssh/sshd_config` is correct, and can be verified by ensuring that the following line appears:
    Protocol 2
Warning: As of `openssh-server` version `7.4` and above, the only protocol supported is version 2, and line
    Protocol 2
in `/etc/ssh/sshd_config` is not necessary.
Rationale: | SSH protocol version 1 is an insecure implementation of the SSH protocol and has many well-known vulnerability exploits. Exploits of the SSH daemon could provide immediate root access to the system.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_allow_only_protocol2
Identifiers and References | References: NT007(R1), 1, 12, 15, 16, 5, 8, 5.5.6, APO13.01, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.13, 3.5.4, CCI-000197, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 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, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, 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, 0487, 1449, 1506, A.11.2.6, A.13.1.1, A.13.2.1, A.14.1.3, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1, CM-6(a), AC-17(a), AC-17(2), IA-5(1)(c), SC-13, MA-4(6), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.PT-4, SRG-OS-000074-GPOS-00042, SRG-OS-000480-GPOS-00227, SRG-OS-000033-VMM-000140
#### Rule Disable SSH Access via Empty Passwords [ref]
Disallow SSH login with empty passwords. The default SSH configuration disables logins with empty passwords. The appropriate configuration is used if no value is set for `PermitEmptyPasswords`. To explicitly disallow SSH login from accounts with empty passwords, add or correct the following line in `/etc/ssh/sshd_config`:
    PermitEmptyPasswords no
Any accounts with empty passwords should be disabled immediately, and PAM configuration should prevent users from being able to assign themselves empty passwords.
Rationale: | Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_disable_empty_passwords
Identifiers and References | References: NT007(R17), 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, 5.5.6, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, 3.1.1, 3.1.5, CCI-000366, CCI-000766, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, FIA_UAU.1, SRG-OS-000106-GPOS-00053, SRG-OS-000480-GPOS-00229, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

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

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    - name: Disable SSH Access via Empty Passwords
      block:

        - name: Check for duplicate values
          lineinfile:
            path: /etc/ssh/sshd_config
            create: false
            regexp: (?i)^\s*PermitEmptyPasswords\s+
            state: absent
          check_mode: true
          changed_when: false
          register: dupes

        - name: Deduplicate values from /etc/ssh/sshd_config
          lineinfile:
            path: /etc/ssh/sshd_config
            create: false
            regexp: (?i)^\s*PermitEmptyPasswords\s+
            state: absent
          when: dupes.found is defined and dupes.found > 1

        - name: Insert correct line to /etc/ssh/sshd_config
          lineinfile:
            path: /etc/ssh/sshd_config
            create: true
            regexp: (?i)^\s*PermitEmptyPasswords\s+
            line: PermitEmptyPasswords no
            state: present
            insertbefore: ^[#\s]*Match
            validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - CJIS-5.5.6
        - NIST-800-171-3.1.1
        - NIST-800-171-3.1.5
        - NIST-800-53-AC-17(a)
        - NIST-800-53-CM-6(a)
        - NIST-800-53-CM-7(a)
        - NIST-800-53-CM-7(b)
        - high_severity
        - low_complexity
        - low_disruption
        - no_reboot_needed
        - restrict_strategy
        - sshd_disable_empty_passwords
#### Rule Disable SSH Root Login [ref]
The root user should never be allowed to login to a system directly over a network. To disable root login via SSH, add or correct the following line in `/etc/ssh/sshd_config`:
    PermitRootLogin no
Rationale: | Even though the communications channel may be encrypted, an additional layer of security is gained by extending the policy of not logging directly on as root. In addition, logging in with a user-specific account provides individual accountability of actions performed on the system and also helps to minimize direct attack attempts on root's password.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_disable_root_login
Identifiers and References | References: BP28(R19), NT007(R21), 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.6, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.1.5, CCI-000366, CCI-000770, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 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, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, 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, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-6(2), AC-17(a), IA-2, IA-2(5), CM-7(a), CM-7(b), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, FIA_UAU.1, SRG-OS-000109-GPOS-00056, SRG-OS-000480-GPOS-00227, SRG-OS-000480-VMM-002000
Remediation Shell script ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*PermitRootLogin\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

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

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi
Remediation Ansible snippet ⇲
Complexity: | low
Disruption: | low
Strategy: | restrict
    - name: Disable SSH Root Login
      block:

        - name: Check for duplicate values
          lineinfile:
            path: /etc/ssh/sshd_config
            create: false
            regexp: (?i)^\s*PermitRootLogin\s+
            state: absent
          check_mode: true
          changed_when: false
          register: dupes

        - name: Deduplicate values from /etc/ssh/sshd_config
          lineinfile:
            path: /etc/ssh/sshd_config
            create: false
            regexp: (?i)^\s*PermitRootLogin\s+
            state: absent
          when: dupes.found is defined and dupes.found > 1

        - name: Insert correct line to /etc/ssh/sshd_config
          lineinfile:
            path: /etc/ssh/sshd_config
            create: true
            regexp: (?i)^\s*PermitRootLogin\s+
            line: PermitRootLogin no
            state: present
            insertbefore: ^[#\s]*Match
            validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
        - CJIS-5.5.6
        - NIST-800-171-3.1.1
        - NIST-800-171-3.1.5
        - NIST-800-53-AC-17(a)
        - NIST-800-53-AC-6(2)
        - NIST-800-53-CM-6(a)
        - NIST-800-53-CM-7(a)
        - NIST-800-53-CM-7(b)
        - NIST-800-53-IA-2
        - NIST-800-53-IA-2(5)
        - low_complexity
        - low_disruption
        - medium_severity
        - no_reboot_needed
        - restrict_strategy
        - sshd_disable_root_login

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