RHEL 9 SSH public host key files must have mode 0644 or less permissive.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-258001 | RHEL-09-255125 | SV-258001r991589_rule | CCI-000366 | medium |
| Description | ||||
| If a public host key file is modified by an unauthorized user, the SSH service may be compromised. | ||||
| STIG | Date | |||
| Red Hat Enterprise Linux 9 Security Technical Implementation Guide | 2025-05-14 | |||
Details
Check Text (C-258001r991589_chk)
Verify the SSH public host key files have a mode of "0644" or less permissive with the following command:
Note: SSH public key files may be found in other directories on the system depending on the installation.
$ sudo stat -c "%a %n" /etc/ssh/*.pub
644 /etc/ssh/ssh_host_dsa_key.pub
644 /etc/ssh/ssh_host_ecdsa_key.pub
644 /etc/ssh/ssh_host_ed25519_key.pub
644 /etc/ssh/ssh_host_rsa_key.pub
If any key.pub file has a mode more permissive than "0644", this is a finding.
Fix Text (F-61666r925989_fix)
Change the mode of public host key files under "/etc/ssh" to "0644" with the following command:
$ sudo chmod 0644 /etc/ssh/*key.pub
Restart the SSH daemon for the changes to take effect:
$ sudo systemctl restart sshd.service