3CX version 18.0 (Build 908). There is one user that doesn't have any recording files. We are self hosting on OVH. I have used putty to SSH and can see the following. The Ext with no recording files is 208.
Very tricky subject! While one could easily google it and and type a few commands in, we strongly advise against touching anything in SSH and we consider modified linux system as not eligible for support (for good reasons of course, not a decision we took lightly).
The terminal is a bit TOO power if you know what I mean, and 3CX really does rely on an unmodified system to function correctly.
Personally if had doubts about my machine's integrity, I'd get a full backup, scrap the VM and redeploy a fresh one and restore my backup just to be on the safe side. At this point it's entirely up to you