Verify Group Who Owns /etc/at.deny file

Description

If /etc/at.deny exists, it must be group-owned by root. To properly set the group owner of /etc/at.deny, run the command:

$ sudo chgrp root /etc/at.deny

Rationale

If the owner of the at.deny file is not set to root, the possibility exists for an unauthorized user to view or edit sensitive information.

Remediation

Shell script

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

#!/bin/bash

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

if getent group "0" >/dev/null 2>&1; then
  newgroup="0"
fi
if [[ -z ${newgroup} ]]; then
  echo "0 is not a defined group on the system"
  exit 1
fi
chgrp $newgroup /etc/at.deny

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

Ansible playbook

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

- name: Gather the package facts
  package_facts:
    manager: auto
  tags:
  - configure_strategy
  - file_groupowner_at_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Set the file_groupowner_at_deny_newgroup variable if represented by gid
  set_fact:
    file_groupowner_at_deny_newgroup: '0'
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - configure_strategy
  - file_groupowner_at_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Test for existence /etc/at.deny
  stat:
    path: /etc/at.deny
  register: file_exists
  when: '"linux-base" in ansible_facts.packages'
  tags:
  - configure_strategy
  - file_groupowner_at_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure group owner on /etc/at.deny
  file:
    path: /etc/at.deny
    group: '{{ file_groupowner_at_deny_newgroup }}'
  when:
  - '"linux-base" in ansible_facts.packages'
  - file_exists.stat is defined and file_exists.stat.exists
  tags:
  - configure_strategy
  - file_groupowner_at_deny
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed