Infected games under Proton.
Infected games under Proton.
I was just wondering what would happen if I downloaded a game that was infected by a computer virus and ran it in Linux using Proton.
Has this happened to anyone? How would the virus behave? What files, connections or devices would it have access to? Could it be as damaging as running in in Windows?
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I was just wondering what would happen if I downloaded a game that was infected by a computer virus and ran it in Linux using Proton.
Depends on the mechanism. Some viruses will target stuff that WINE doesn't emulate -- like, if it tries to fiddle with Windows system files, it's just not going to work. But, sure, a Windows executable could look for and infect other Widows executables.
Has this happened to anyone?
I don't know specifically about viruses or on Proton. But there has been Windows malware that works under WINE. Certainly it's technically possible.
How would the virus behave?
Depends entirely on the virus in question. Can't give a generic answer to that.
What files, connections or devices would it have access to?
WINE itself doesn't isolate things (which probably is reasonable, given that it's a huge, often-changing system and not the best place to enforce security restrictions). On a typical Linux box, anything that you, as a user, would, since Linux user-level restrictions would be the main place where security restrictions would come into play.
I do think that there's a not-unreasonable argument that Valve should default to having games -- not just Proton stuff -- run in some kind of isolation by default. Basically, games generally are gonna need 3d access, and some are gonna need access to specialized input devices. But Steam games mostly don't need general access to your system. But as things stand, Steam doesn't do any kind of isolation either.
You can isolate Steam as a whole -- you can look at installing Steam via flatpak, for one popular option. I don't use flatpaks, so I'm not terribly familiar with the system, but I understand that those isolate the filesystem that Steam and its games have access to. That being said, it doesn't isolate games from each other, or from Steam (e.g. I can imagine a Steam-credentials-stealing piece of malware making it into the Steam Workshop). On the other hand, I'm not totally sure how much I'd trust Valve to do a solid job of having the Steam API be really hardened against a malicious game anyway -- that's not easy -- so maybe isolating Steam too is a good idea.
Could it be as damaging as running in in Windows?
Sure. If it's not Linux-aware, it probably isn't going to do anything worse than deleting all the files that your user has access to, but in general, that'd be about as bad anyway. If it is Linux-aware, it could probably do something like intercept your password next time you invoke
sudo, then make use of it to act as root and do anything.Ah see I didn't think of the flatpak aspect. But if you download a game from some shady source and want to run it via flatpak Steam, how would you go about it?
I only use Steam as a regular deb install.
Yeah, I use Steam as a deb too.
I haven't done it, but as long as Steam itself is isolated -- as I expect flatpak Steam is -- anything it launches will be too, and you can add arbitrary binaries. AFAIK, that works with Windows binaries in Proton.
https://help.steampowered.com/en/faqs/view/4B8B-9697-2338-40EC.
Referring to your response to dillekant, I'm not sure how much Steam buys you in terms of security, though, unless you're buying from Valve. The flatpak might provide some isolation by virtue of being flatpak (though I dunno how many permissions the Steam flatpak is granted...I assume that at bare minimum, it has to grant games access to stuff like your microphone to let VoIP chat work).
https://docs.flatpak.org/en/latest/sandbox-permissions.html
Steam, itself as of today, doesn't provide isolation, at all.
Adding a non-Steam game to Steam lets you launch from Steam, which might be convenient. Maybe use Proton, which has a few compatibility patches.
If I wanted to run an untrusted Windows binary game today on my Linux box, if it needs 3d acceleration, I don't have a great answer. If it doesn't, then running it in a Windows VM with qemu is probably what I'd do -- I keep a "throwaway" VM for exactly that. It has read access to a shared directory, and write access to a "dropbox" directory. I wouldn't bring Steam into the picture at all. I don't want it near my Steam credentials (Steam credentials have been a target of malware in the part) or a big software package like Steam that may-or-may-not have been well-hardened.
It does get network access to my internal network -- I haven't set up an outbound firewall on the bridge, so a hostile binary could get whatever unauthenticated access it could get from my LAN. And it could use my Internet connection, maybe participate in a DDoS of someone or such. But it doesn't otherwise have access to the system. It isn't per-app isolation, but if the VM vanished today, it wouldn't be a problem -- there's nothing sensitive on it. It doesn't know my name. It can't talk to my hardware, outside of what's virtualized. It doesn't have access to my data. There are no credentials that enter that VM. Unless qemu itself has security holes, software in the thing is limited to the VM.
I have used
firejailto sandbox some Linux-native apps, but while it's a neat hack, and has a lot of handy tools to isolate software, I have a hard time recommending it as a general solution for untrusted binaries. I don't know how viable it is to use with WINE, which it sounds like is what you want. It has a lot of "default insecure" behavior, where you need to blacklist a program for access to a resource, rather than whitelisting it. From a security standpoint I'd much rather have something more like Android, wherefirejailstarts a new app with no permissions, warns me if it's trying to use a resource (network, graphical environment certain directories) and asks me if I want to whitelist that access. It requires some technical and security familiarity to use. I think the most-useful thing I've used it for is that it mostly can isolate Ren'Py games, cut network access, disk write access, and a number of games (though not all; arbitrary Python libraries can be bundled) can work with a reasonably-generic restrictivefirejailrenpy profile. It just requires too much fiddling and knowledge to be a general solution for all users, and "default insecure" is trouble, IMHO.I do wish that there was some kind of reliable, no-fiddling, lighter-weight per-game isolation available for both Windows binaries and Linux binaries out-of-box. Like, that Joe User can use and I could recommend.
I did see something the other day when reading about an unrelated Proxmox issue, talking about Nvidia apparently having some kind of GPU virtualization support. And searching, it looks like AMD has some kind of "multiuser GPU" thing that they're billing. I don't know how hardened either's drivers are, but running VMs with 3d games may have become more practical since last I looked.
EDIT: Hmm, yeah, sounds like QEMU does have some kind of GPU virtualization these days:
https://ubuntu.com/server/docs/gpu-virtualization-with-qemu-kvm
Need native performance, but multiple guests per card: Like with PCI passthrough, but using mediated devices to shard a card on the host into multiple devices, then passing those:
-display gtk,gl=on -device vfio-pci,sysfsdev=/sys/bus/pci/devices/0000:00:02.0/4dd511f6-ec08-11e8-b839-2f163ddee3b3,display=on,rombar=0
You can read more about vGPU at kraxel and Ubuntu GPU mdev evaluation. The sharding of the cards is driver-specific and therefore will differ per manufacturer – Intel, Nvidia, or AMD.
I haven't looked into that before, though. Dunno what, if any, issues there are.
EDIT2: Okay, I am sorry. I am apparently about four years out of date on Steam. Steam didn't have any form of isolation, but apparently in late 2020, they added Pressure Vessel, some form of lxc-based per-game containerization.
I don't know what it isolates, though. I may need to poke more at that. Pretty sure that it doesn't block network access, and I dunno what state the container gets access to.
If you don't use steam because it's a shady source, I guess Bottles would be your go-to. I think parent is talking about if you bought a game off steam.
No no, I mean if someone downloads an infected pirated game from some shady website. I consider Steam to be very secure.
In that case Steam flatpak isn't really what you want. You probably want to use Bottles, which creates a flatpak-like sandbox. This is not a guarantee or anything, but does give you some protection (at least, better than running it on Windows I guess).
Neat! Man I'm learning so much in this thread it's crazy. Thank you!