Ubuntu OS must not allow unattended or automatic login via SSH.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| high | V-275620 | SRG-OS-000480-GPOS-00229 | RIIM-OS-255025 | SV-275620r1147910_rule | 2025-10-02 | 1 |
Description
Failure to restrict system access to authenticated users negatively impacts Ubuntu OS security.
ℹ️ Check
Verify 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
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