Verify User Who Owns shadow File
Description
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.
Shell script
The following script can be run on the host to remediate the issue.
#!/bin/bash
if id "0" >/dev/null 2>&1; then
newown="0"
fi
if [[ -z ${newown} ]]; then
echo "0 is not a defined user on the system"
exit 1
fi
chown $newown /etc/shadow
Ansible playbook
The following playbook can be run with Ansible to remediate the issue.
- name: Set the file_owner_etc_shadow_newown variable if represented by uid
set_fact:
file_owner_etc_shadow_newown: '0'
tags:
- CJIS-5.5.2.2
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSS-Req-8.7.c
- PCI-DSSv4-2.2
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- 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
- PCI-DSSv4-2.2
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
- name: Ensure owner on /etc/shadow
file:
path: /etc/shadow
owner: '{{ file_owner_etc_shadow_newown }}'
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
- PCI-DSSv4-2.2
- PCI-DSSv4-2.2.6
- configure_strategy
- file_owner_etc_shadow
- low_complexity
- low_disruption
- medium_severity
- no_reboot_needed
