Ubuntu 22.04 LTS must not allow unattended or automatic login via SSH.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-260526 | UBTU-22-255025 | SV-260526r991591_rule | CCI-000366 | high |
| Description | ||||
| Failure to restrict system access to authenticated users negatively impacts Ubuntu 22.04 LTS security. | ||||
| STIG | Date | |||
| Canonical Ubuntu 22.04 LTS Security Technical Implementation Guide | 2025-05-16 | |||
Details
Check Text (C-260526r991591_chk)
Verify that unattended or automatic login via SSH is disabled by using the following command:
$ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iEH '(permit(.*?)(passwords|environment))'
/etc/ssh/sshd_config:PermitEmptyPasswords no
/etc/ssh/sshd_config:PermitUserEnvironment no
If "PermitEmptyPasswords" and "PermitUserEnvironment" are not set to "no", are commented out, are missing, or conflicting results are returned, this is a finding.
Fix Text (F-64163r953390_fix)
Configure the SSH server to not allow unattended or automatic login to the system.
Add or modify the following lines in the "/etc/ssh/sshd_config" file:
PermitEmptyPasswords no
PermitUserEnvironment no
Restart the SSH daemon for the changes to take effect:
$ sudo systemctl restart sshd.service