TOSS 5 SSH private host key files must have mode 0640 or less permissive.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-282709 | SRG-OS-000480-GPOS-00227 | TOSS-05-000253 | SV-282709r1201369_rule | 2026-04-01 | 1 |
Description
If an unauthorized user obtains the private SSH host key file, the host could be impersonated.
ℹ️ Check
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
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