The TOSS SSH private host key files must have mode 0600 or less permissive.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-253107 | TOSS-04-040660 | SV-253107r991589_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) 4 Security Technical Implementation Guide | 2025-05-08 | |||
Details
Check Text (C-253107r991589_chk)
Verify the SSH private host key files have mode "0600" or less permissive with the following command:
$ sudo ls -l /etc/ssh/ssh_host*key
-rw------- 1 root ssh_keys 668 Nov 28 06:43 ssh_host_dsa_key
-rw------- 1 root ssh_keys 582 Nov 28 06:43 ssh_host_key
-rw------- 1 root ssh_keys 887 Nov 28 06:43 ssh_host_rsa_key
If any private host key file has a mode more permissive than "0600", this is a finding.
Fix Text (F-56510r824992_fix)
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
The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command:
$ sudo systemctl restart sshd.service