The TOSS SSH private host key files must have mode 0600 or less permissive.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-253107	SRG-OS-000480-GPOS-00227	TOSS-04-040660	SV-253107r991589_rule	2024-05-30	2

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 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.

ℹ️ Check

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
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