Can malware picked up by a user on my server affect other users if they are not in the same group? I am using the server for backups and storage for a small number of users, and users can also interact with their files through nautilus.
I think this question is hard to answer. Generally speaking, if the “malware” can do privelige escalation and turn the regular, non-priveliged user into root, then everybody on that system can be affected.
backup and storage in one server doesn’t seem to be the best choice. Can’t you split this into two machines?
Is it so easy to just turn a non-privileged user into root? Wouldn’t that blow up the entire concept of root and non-root users?
Unfortunately I don’t have 2 machines, so trying to make the best of what I have
no, it’s certainly not easy, but sometimes bugs surface that allow for a privilige escalation. It’s not very likely but it’s not impossible.
Users don’t login to that machine, do they? The just mount a share from that server, right? so, there is no way they can mess around with the actual system, they just read and write to a network share…
Well, theoretically not. And Fedora is built to make security a top priority, even at the expense of the convenience of regular use. But practically, it can happen that someone overcomes the lock.
You can further increase security by
- not granting shell access to regular users if possible
- installing software like fail2ban
- only allowing remote login (ssh) by key, no longer by password.
Furthermore, it makes sense to separate the services that require a user account from the regular server operation. You can either “lock” them into a system container, which practically does not increase the server load (see Container systemd-nspawn – Installation :: Fedora Docs) and does not cause any additional workload for the system administration. This way is also suitable for smaller, less powerful servers with less RAM. Or you can create a virtual machine (see Adding Virtualization Support :: Fedora Docs).
Thanks for your good ideas. I am more worried about some malware picked up by my users from stupidity on their own computers much more than an attack on the server itself. Besides I will probably run it on lan only.