The RHEL 8 SSH daemon must not allow authentication using known host’s authentication.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-230290	RHEL-08-010520	SV-230290r951602_rule		Medium

Description
Configuring this setting for the SSH daemon provides additional assurance that remote logon via SSH will require a password, even in the event of misconfiguration elsewhere.

STIG	Date
Red Hat Enterprise Linux 8 Security Technical Implementation Guide	2024-02-19

Details

Check Text ( C-32959r951601_chk )
Verify the SSH daemon does not allow authentication using known host’s authentication with the following command: $ sudo /usr/sbin/sshd -dd 2>&1 \| awk '/filename/ {print $4}' \| tr -d '\r' \| tr '\n' ' ' \| xargs sudo grep -iH '^\s*ignoreuserknownhosts' IgnoreUserKnownHosts yes If the value is returned as "no", the returned line is commented out, or no output is returned, this is a finding. If conflicting results are returned, this is a finding.

Check Text ( C-32959r951601_chk )

Verify the SSH daemon does not allow authentication using known host’s authentication with the following command:

$ sudo /usr/sbin/sshd -dd 2>&1 | awk '/filename/ {print $4}' | tr -d '\r' | tr '\n' ' ' | xargs sudo grep -iH '^\s*ignoreuserknownhosts'

IgnoreUserKnownHosts yes

If the value is returned as "no", the returned line is commented out, or no output is returned, this is a finding.

If conflicting results are returned, this is a finding.

Fix Text (F-32934r567617_fix)
Configure the SSH daemon to not allow authentication using known host’s authentication. Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes": IgnoreUserKnownHosts yes The SSH daemon must be restarted for the changes to take effect. To restart the SSH daemon, run the following command: $ sudo systemctl restart sshd.service