Verify Permissions on /etc/shells File

Description

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

$ sudo chmod 0644 /etc/shells

Rationale

The /etc/shells file contains the list of full pathnames to shells on the system. Since this file is used by many system programs this file should be protected.

Remediation

Shell script

The following script can be run on the host to remediate the issue.

#!/bin/bash

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

Ansible playbook

The following playbook can be run with Ansible to remediate the issue.

- name: Test for existence /etc/shells
  stat:
    path: /etc/shells
  register: file_exists
  tags:
  - CCE-86626-9
  - NIST-800-53-AC-3
  - NIST-800-53-MP-2
  - configure_strategy
  - file_permissions_etc_shells
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure permission u-xs,g-xws,o-xwt on /etc/shells
  file:
    path: /etc/shells
    mode: u-xs,g-xws,o-xwt
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - CCE-86626-9
  - NIST-800-53-AC-3
  - NIST-800-53-MP-2
  - configure_strategy
  - file_permissions_etc_shells
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed