Ubuntu 24.04 LTS must not allow unattended or automatic login via SSH.

Failure to restrict system access to authenticated users negatively impacts Ubuntu 24.04 LTS security.

Verify unattended or automatic login via SSH is disabled with the following command:

$ egrep -r '(Permit(.*?)(Passwords|Environment))' /etc/ssh/sshd_config PermitEmptyPasswords no PermitUserEnvironment no

If the "PermitEmptyPasswords" or "PermitUserEnvironment" keywords are set to a value other than "no", are commented out, are both missing, or conflicting results are returned, this is a finding.

Configure Ubuntu 24.04 LTS to allow the SSH daemon to not allow unattended or automatic login to the system.

Add or edit the following lines in the "/etc/ssh/sshd_config" file:

PermitEmptyPasswords no PermitUserEnvironment no

Restart SSH for the changes to take effect:

$ sudo systemctl restart ssh