Yes, yes I know there are no real passwords or even hashes in that file on modern systems. However, I am quite curious if this is a good, easy way to totally lock down a system from everyone and what would break first. I don't have a spare system, but it sure sounds like a fun experiment. Has anyone tried this?
Just for you I tried it :-)
Any user will be able to login like normal. This is because login runs with root privileges. After being logged in the user won't have access to
The first thing you might notice is that the shell cannot read your username which produce a prompt like
Setup an auditctl on /etc/passwd and see what tries to access it:
Then afterwards analyse the output of:
See what's trying to access it, if it's all root processes then you're fine.