RHEL 9 must not allow a noncertificate trusted host SSH logon to the system.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-257992	RHEL-09-255080	SV-257992r991591_rule		Medium

Description
SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.

STIG	Date
Red Hat Enterprise Linux 9 Security Technical Implementation Guide	2024-06-04

Details

Check Text ( C-61733r952189_chk )
Verify the operating system does not allow a noncertificate trusted host SSH logon to the system 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*hostbasedauthentication' HostbasedAuthentication no If the "HostbasedAuthentication" keyword is not set to "no", is missing, or is commented out, this is a finding. If the required value is not set, this is a finding.

Check Text ( C-61733r952189_chk )

Verify the operating system does not allow a noncertificate trusted host SSH logon to the system 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*hostbasedauthentication'

HostbasedAuthentication no

If the "HostbasedAuthentication" keyword is not set to "no", is missing, or is commented out, this is a finding.

If the required value is not set, this is a finding.

Fix Text (F-61657r925962_fix)
To configure RHEL 9 to not allow a noncertificate trusted host SSH logon to the system add or modify the following line in "/etc/ssh/sshd_config". HostbasedAuthentication no Restart the SSH daemon for the settings to take effect: $ sudo systemctl restart sshd.service