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V-253106

CAT II (Medium)

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

Rule ID

SV-253106r991589_rule

STIG

Tri-Lab Operating System Stack (TOSS) 4 Security Technical Implementation Guide

Version

V2R5

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 grep -i strictmodes /etc/ssh/sshd_config

StrictModes yes

If "StrictModes" is set to "no", is missing, or the returned line is commented out, 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