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.

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