Verify Permissions on SSH Server config file
Description
To properly set the permissions of /etc/ssh/sshd_config, run the command:
$ sudo chmod 0600 /etc/ssh/sshd_config
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 be owned by the
correct group to prevent unauthorized changes.
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/ssh/sshd\_config
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/ssh/sshd\_config
stat:
path: /etc/ssh/sshd\_config
register: file\_exists
when: ansible\_virtualization\_type not in ["docker", "lxc", "openvz", "podman", "container"]
tags:
- NIST-800-53-AC-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure\_strategy
- file\_permissions\_sshd\_config
- low\_complexity
- low\_disruption
- medium\_severity
- no\_reboot\_needed
- name: Ensure permission u-xs,g-xwrs,o-xwrt on /etc/ssh/sshd\_config
file:
path: /etc/ssh/sshd\_config
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-17(a)
- NIST-800-53-AC-6(1)
- NIST-800-53-CM-6(a)
- PCI-DSSv4-2.2.6
- configure\_strategy
- file\_permissions\_sshd\_config
- low\_complexity
- low\_disruption
- medium\_severity
- no\_reboot\_needed
