6.1.6 Ensure permissions on /etc/shadow- are configured

Information

The /etc/shadow- file is used to store backup information about user accounts that is critical to the security of those accounts, such as the hashed password and other security information.

It is critical to ensure that the /etc/shadow- file is protected from unauthorized access. Although it is protected by default, the file permissions could be changed either inadvertently or through malicious actions.

Solution

Run the one of the following chown commands as appropriate and the chmod to set permissions on /etc/shadow- :

# chown root:root /etc/shadow-
# chown root:shadow /etc/shadow-

# chmod o-rwx,g-rw /etc/shadow-

See Also

https://workbench.cisecurity.org/benchmarks/12218