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V-248603

CAT II (Medium)

The OL 8 SSH daemon must perform strict mode checking of home directory configuration files.

Rule ID

SV-248603r991589_rule

STIG

Oracle Linux 8 Security Technical Implementation Guide

Version

V2R8

CCIs

CCI-000366

Discussion

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

Check Content

Verify the SSH daemon performs strict mode checking of home directory configuration files 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*strictmodes'

StrictModes yes

If "StrictModes" is set to "no" or is missing, or if the returned line is commented out, this is a finding. 

If conflicting results are returned, this is a finding.

Fix Text

Configure SSH to perform strict mode checking of home directory configuration files.  
 
Uncomment the "StrictModes" keyword in "/etc/ssh/sshd_config" and set the value to "yes": 
 
StrictModes 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