The Ubuntu operating system must not allow unattended or automatic login via SSH.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-238218	UBTU-20-010047	SV-238218r877377_rule		High

Description
Failure to restrict system access to authenticated users negatively impacts Ubuntu operating system security.

STIG	Date
Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide	2023-12-01

Details

Check Text ( C-41428r858530_chk )
Verify that 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 "PermitEmptyPasswords" or "PermitUserEnvironment" keywords are not set to "no", are missing completely, or are commented out, this is a finding. If conflicting results are returned, this is a finding.

Check Text ( C-41428r858530_chk )

Verify that 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 "PermitEmptyPasswords" or "PermitUserEnvironment" keywords are not set to "no", are missing completely, or are commented out, this is a finding.
If conflicting results are returned, this is a finding.

Fix Text (F-41387r653828_fix)
Configure the Ubuntu operating system 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 the SSH daemon for the changes to take effect: $ sudo systemctl restart sshd.service