The /etc/shadow file contains the one-way cipher text passwords for each user defined in the /etc/passwd file. The command below sets the user and group ownership of the file to root. Rationale: If attackers can gain read access to the /etc/shadow file, they can easily run a password cracking program against the hashed password to break it. Other security information that is stored in the /etc/shadow file (such as expiration) could also be useful to subvert the user accounts.

[UID of ROOT, GID of shadow]

If the ownership of the /etc/shadow file are incorrect, run the following command to correct them: # /bin/chown root:shadow /etc/shadow