I noticed Debian does this by default and Arch wiki recommends is citing improved security and upstream.
I don’t get why that’s more secure. Is this assuming torrents might be infected and aims to limit what a virus may access to the dedicated user’s home directory (/var/lib/transmission-daemon on Debian)?
It’s more the situation where the torrent/magnet string itself (or some peer connection) has some clever hack that exploits a bug in Transmission, allowing it to execute arbitrary code AS transmission. I’m skeptical there’s a big risk of that, but the security theater kids LOVE sand boxing these days
It may be mostly “security theater” but it requires almost no extra effort and drastically increases the difficulty of compromise by adding privilege escalation as another requirement to gaining root access.
Has there ever been such an exploit? Given all other torrent clients I’ve seen just run as your user by default, is there something different in transmission over others that make it more vulnerable?
Not yet, but if every system was only protected against what already happened instead of also what could happen, we’d get hacked a lot more often!
The point is also to minimize potential damages caused by a bug in the software. Just this year there have been multiple data-destroying bugs in publicly released software. If the app runs as a server it’s usually trivial to have it run as a dedicated user, with just enough permissions to do its job.
It’s just good practice, even though the risks might be low why risk it at all?
Not of which I’m aware. Transmission is more intended to run on a server though. You certainly can just run the local GUI, but it can run as a daemon on a server and then you can use a web interface or app, so its working more on a server v user app paradigm (Everything on a modern server like that is gonna run as its own user)