Verify Permissions on crontab

Classification:

compliance

Framework:

Control:

Description

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

$ sudo chmod 0600 /etc/crontab

Rationale

Service configuration files enable or disable features of their respective services that if configured incorrectly can lead to insecure and vulnerable configurations. Therefore, service configuration files should have the correct access rights to prevent unauthorized changes.

Remediation

Shell script

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

# Remediation is applicable only in certain platforms
if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

chmod u-xs,g-xwrs,o-xwrt /etc/crontab

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: Test for existence /etc/crontab
 stat:
 path: /etc/crontab
 register: file\_exists
 when: ansible\_virtualization\_type not in ["docker", "lxc", "openvz", "podman", "container"]
 tags:
 - NIST-800-53-AC-6(1)
 - NIST-800-53-CM-6(a)
 - PCI-DSSv4-2.2.6
 - configure\_strategy
 - file\_permissions\_crontab
 - low\_complexity
 - low\_disruption
 - medium\_severity
 - no\_reboot\_needed

- name: Ensure permission u-xs,g-xwrs,o-xwrt on /etc/crontab
 file:
 path: /etc/crontab
 mode: u-xs,g-xwrs,o-xwrt
 when:
 - ansible\_virtualization\_type not in ["docker", "lxc", "openvz", "podman", "container"]
 - file\_exists.stat is defined and file\_exists.stat.exists
 tags:
 - NIST-800-53-AC-6(1)
 - NIST-800-53-CM-6(a)
 - PCI-DSSv4-2.2.6
 - configure\_strategy
 - file\_permissions\_crontab
 - low\_complexity
 - low\_disruption
 - medium\_severity
 - no\_reboot\_needed