RHEL 9 SSH daemon must perform strict mode checking of home directory configuration files.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-258008	RHEL-09-255160	SV-258008r926011_rule		Medium

Description
If other users have access to modify user-specific SSH configuration files, they may be able to log into the system as another user.

STIG	Date
Red Hat Enterprise Linux 9 Security Technical Implementation Guide	2023-12-01

Details

Check Text ( C-61749r926009_chk )
Verify the SSH daemon performs strict mode checking of home directory configuration files with the following command: $ sudo grep -ir strictmodes /etc/ssh/sshd_config /etc/ssh/sshd_config.d/* StrictModes yes If the "StrictModes" keyword is set to "no", the returned line is commented out, or no output is returned, this is a finding.

Fix Text (F-61673r926010_fix)
Configure the SSH daemon to perform strict mode checking of home directory configuration files. Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes": StrictModes yes The SSH service must be restarted for changes to take effect: $ sudo systemctl restart sshd.service