InformationThe /etc/shadow file is used to store the information about user accounts that is critical to the security of those accounts, such as the hashed password and other security information.
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.
SolutionRun one of the following commands to set ownership of /etc/shadow to root and group to either root or shadow:
# chown root:root /etc/shadow
# chown root:shadow /etc/shadow
Run the following command to remove excess permissions form /etc/shadow:
# chmod u-x,g-wx,o-rwx /etc/shadow