Vulnerability Discussion
Providing users feedback on when account accesses last occurred facilitates user recognition and reporting of unauthorized account use.
Check
Verify the SSH daemon provides users with feedback on when account accesses last occurred 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*printlastlog'
PrintLastLog yes
If the "PrintLastLog" keyword is set to "no", the returned line is commented out, or no output is returned, this is a finding.
Fix
Configure the SSH daemon to provide users with feedback on when account accesses last occurred.
Add the following line in "/etc/ssh/sshd_config", or uncomment the line and set the value to "yes":
PrintLastLog yes
The SSH service must be restarted for changes to take effect:
$ sudo systemctl restart sshd.service