TOSS 5 SSH private host key files must have mode 0640 or less permissive.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-282709 | TOSS-05-000253 | SV-282709r1201369_rule | CCI-000366 | medium |
| Description | ||||
| If an unauthorized user obtains the private SSH host key file, the host could be impersonated. | ||||
| STIG | Date | |||
| Tri-Lab Operating System Stack (TOSS) 5 Security Technical Implementation Guide | 2026-04-01 | |||
Details
Check Text (C-282709r1201369_chk)
Verify the SSH private host key files have a mode of "0640" or less permissive using 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 (F-87175r1201368_fix)
Configure the mode of SSH private host key files under "/etc/ssh" to "0640" using 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