Comment 4 for bug 1923262

The cisecurity guide is wrong. While there is info that could be leveraged, but on a modern system the really sensitive information is split out into /etc/shadow (which very much should be only readable by root). The reality is that on a modern system /etc/passwd needs to be world readable (it is the local user db) for several applications that users can and do use (eg. ls being able to display who owns a file).

If /etc/passwd is world readable, there is no point in changing the permissions on the backup file.

If you don't want /etc/passwd be available to all applications/users. You can use a MAC system to further restrict access to /etc/passwd and its backup file.