Vulnerability Discussion
The "/etc/shadow" file stores password hashes. Protection of this file is critical for system security.
Check
Verify the group ownership of the "/etc/shadow" file with the following command:
$ sudo stat -c "%G %n" /etc/shadow
root /etc/shadow
If "/etc/shadow" file does not have a group owner of "root", this is a finding.
Fix
Change the group of the file /etc/shadow to root by running the following command:
$ sudo chgrp root /etc/shadow