users with bin/bash access

Question

I was following the guide here and listed all users in passwd. There I found the following problems:

/bin/false aparently allows channels and some form of forwarding

nm-openconnect:x:122:130:NetworkManager OpenConnect plugin,,,:/var/lib/NetworkManager:/bin/false

is this forwarding still possible with /bin/false nowadays (16.02)?

guest-2lq2jn:x:998:997:Guest:/tmp/guest-2lq2jn:/bin/bash

I don't know who this is or why this account exists. Its history is empty but it does seem to have root access. What should I do?

postgres:x:123:132:PostgreSQL administrator,,,:/var/lib/postgresql:/bin/bash

Why does postgreSQL have /bin/bash access? Is this normal?

I am sorry for asking three questions in one, but it can be hard to get one answered and it seems like they are sub-questions.

Answer 1

/bin/false is a simple program which does nothing, and returns a status code indicating failure. you can still use it. It's a part of coreutils package so it's available by default.

"guest" line is related to Ubuntu guest user and does not have any harm or any spacial permissions to do anything to your system, it's a normal user which has access to bash however it can do nothing and all it's data are temporary.

about "postgres", it might need a bash to do a specific task.