The TOSS SSH daemon must not allow Kerberos authentication, except to fulfill documented and validated mission requirements.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-252944 | TOSS-04-010420 | SV-252944r991589_rule | CCI-000366 | medium |
| Description | ||||
| Configuring these settings for the SSH daemon provides additional assurance that remote logon via SSH will not use unused methods of authentication, even in the event of misconfiguration elsewhere. | ||||
| STIG | Date | |||
| Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide | 2025-05-08 | |||
Details
Check Text (C-252944r991589_chk)
Verify the SSH daemon does not allow Kerberos authentication with the following command:
$ sudo grep -i KerberosAuthentication /etc/ssh/sshd_config
KerberosAuthentication no
If the value is returned as "yes", the returned line is commented out, no output is returned, or has not been documented with the ISSO, this is a finding.
Fix Text (F-56347r824155_fix)
Configure the SSH daemon to not allow Kerberos authentication.
Add the following line in "/etc/ssh/sshd_config" or uncomment the line and set the value to "no":
KerberosAuthentication no
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