It is not impossible. SteamOS itself is not “stripped down”, at least that is not the reason why you cannot install packages from AUR. SteamOS has a write protection for the system files and the operating system installation. On top of it, any changes made to it will be reverted back with a system update.
One can enable write permission and install AUR packages. However with the next update the system is usually reverted back and changes like these are lost. Therefore being infected on Steam Deck is unlikely. If anyone did that and got infected during that period of time, then I wouldn’t trust the installation anymore.
Fubarberry@sopuli.xyz 1 week ago
People using the aur on steamOS probably are doing so through distrobox. Distrobox doesn’t sandbox as far as I know, so the infostealer part of the malware would still be a risk. The rootkit part I’m guessing would fail, since I think distrobox on Deck usually runs in rootless mode.
It also seems like there was a fairly short window of time before the infected packages were caught, anyone who didn’t update one of the compromised packages on that exact day should be fine.