Information
The shadow group allows system programs which require access the ability to read the
/etc/shadow file. No users should be assigned to the shadow group.
Rationale:
Any users assigned to the shadow group would be granted read access to the /etc/shadow
file. If attackers can gain read access to the /etc/shadow file, they can easily run a password
cracking program against the hashed passwords to break them. Other security information
that is stored in the /etc/shadow file (such as expiration) could also be useful to subvert
additional user accounts.
Solution
Remove all users from the shadow group, and change the primary group of any users with
shadow as their primary group.