Verify User Who Owns Backup shadow File

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Description

To properly set the group owner of /etc/shadow-, run the command:

$ sudo chgrp shadow /etc/shadow-

Rationale

The /etc/shadow- file is a backup file of /etc/shadow, and as such, it contains the list of local system accounts and password hashes. Protection of this file is critical for system security.

Remediation

Shell script

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

#!/bin/bash

chgrp -L 42 /etc/shadow-

Ansible playbook

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

- name: Test for existence /etc/shadow-
  stat:
    path: /etc/shadow-
  register: file_exists
  tags:
  - PCI-DSS-Req-8.7
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_backup_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:
  - PCI-DSS-Req-8.7
  - PCI-DSSv4-2.2.6
  - configure_strategy
  - file_groupowner_backup_etc_shadow
  - low_complexity
  - low_disruption
  - medium_severity
  - no_reboot_needed