Rule version OL09-00-002502 · STIG v1 · 2026-08-21
If an unauthorized user obtains the private SSH host key file, the host could be impersonated.
Verify that OL 9 SSH private host key files have a mode of "0600" or less permissive with the following command:
$ ls -l /etc/ssh/*_key 600 /etc/ssh/ssh_host_dsa_key 600 /etc/ssh/ssh_host_ecdsa_key 600 /etc/ssh/ssh_host_ed25519_key 600 /etc/ssh/ssh_host_rsa_key
If any private host key file has a mode more permissive than "0600", this is a finding.
Configure the mode of SSH private host key files under "/etc/ssh" to "0600" with the following command:
$ sudo chmod 0600 /etc/ssh/ssh_host*key
Restart the SSH daemon for the changes to take effect:
$ sudo systemctl restart sshd.service