Verify Group Who Owns /var/log/messages File

Description

To properly set the group owner of /var/log/messages, run the command:

$ sudo chgrp root /var/log/messages

Rationale

The /var/log/messages file contains logs of error messages in the system and should only be accessed by authorized personnel.

Remediation

Shell script

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

#!/bin/bash

newgroup=""
if getent group "0" >/dev/null 2>&1; then
  newgroup="0"
fi

if [[ -z "${newgroup}" ]]; then
  >&2 echo "0 is not a defined group on the system"
else
if ! stat -c "%g %G" "/var/log/messages" | grep -E -w -q "0"; then
    chgrp --no-dereference "$newgroup" /var/log/messages
fi

fi

Ansible playbook

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

- name: Set the file_groupowner_var_log_messages_newgroup variable if represented
    by gid
  ansible.builtin.set_fact:
    file_groupowner_var_log_messages_newgroup: '0'
  tags:
  - configure_strategy
  - file_groupowner_var_log_messages
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Test for existence /var/log/messages
  ansible.builtin.stat:
    path: /var/log/messages
  register: file_exists
  tags:
  - configure_strategy
  - file_groupowner_var_log_messages
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed

- name: Ensure group owner on /var/log/messages
  ansible.builtin.file:
    path: /var/log/messages
    follow: false
    group: '{{ file_groupowner_var_log_messages_newgroup }}'
  when: file_exists.stat is defined and file_exists.stat.exists
  tags:
  - configure_strategy
  - file_groupowner_var_log_messages
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed