Title

RHEL 9 SSH private host key files must have mode 0640 or less permissive. (Cat II impact)

Discussion

If an unauthorized user obtains the private SSH host key file, the host could be impersonated.

Check Content

Verify the SSH private host key files have a mode of "0640" or less permissive with the following command: $ ls -l /etc/ssh/*_key 640 /etc/ssh/ssh_host_dsa_key 640 /etc/ssh/ssh_host_ecdsa_key 640 /etc/ssh/ssh_host_ed25519_key 640 /etc/ssh/ssh_host_rsa_key If any private host key file has a mode more permissive than "0640", this is a finding.

Fix Text

Configure the mode of SSH private host key files under "/etc/ssh" to "0640" with the following command: $ sudo chmod 0640 /etc/ssh/ssh_host*key Restart the SSH daemon for the changes to take effect: $ sudo systemctl restart sshd.service

Additional Identifiers

Rule ID: SV-258000r925987_rule

Vulnerability ID: V-258000

Group Title: SRG-OS-000480-GPOS-00227

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.