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		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	2024-05-30

Details

Check Text ( C-64255r953389_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.

Check Text ( C-64255r953389_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