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


Finding ID Version Rule ID IA Controls Severity
V-238218 UBTU-20-010047 SV-238218r877377_rule High
Failure to restrict system access to authenticated users negatively impacts Ubuntu operating system security.
Canonical Ubuntu 20.04 LTS Security Technical Implementation Guide 2022-12-06


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