Almost every program that we run has access to the environment, so nothing stops them from curling our credentials to some nefarious server.
Why don’t we put credentials in files and then pass them to the programs that need them? Maybe coupled with some mechanism that prevents executables from reading any random file except those approved.
From a quick search I’ve just done, the major difference is that
/bin/falsecan’t return any text, the only thing it can do as specified via POSIX standards is returnfalse.So if you set someone’s shell to
/bin/nologinthere can be some text that says “You’re not allowed shell access”, similar to what happens if you try to SSH into say GitHub.Of course, for a service account that won’t be operated by a person, that doesn’t matter - so whichever one you use is just whichever the operator thought of first, most likely.