Playtron are quietly building up their Linux-based PlaytronOS behind the scenes, and not only have they released their first Alpha but they've pulled in another investor too.
Here is the quote I paraphrased in my comment (I’m sure I got something wrong):
The immutable file system from Fedora Silverblue will be very helpful in implementing our anti cheat system but it is not our anti cheat system. We are planning to generate signatures for each version of our OS (easy with Silverblue) as well as all the DLLs we install dynamically. Basically using our SDK, a game developer will be able to obtain a signature of the current config on the device then call our backend to verify that this is a genuine Playtron version.
Ah, so they don’t actually say that they read kernel space. They check the version of all installed packages and checksum the installed DLLs/SOs.
If the user still has root privileges, this may still not prevent sideloading of kernel modules. Even if it would detect a kernel module that has been sideloaded, I believe it’s possible to write a kernel module that will still be resident after you unload it. This kernel module can then basically do anything without the knowledge of userspace. It could for example easily replace any code running in userspace, and their anticheat would miss that as it doesn’t actually check what code is currently running. Most simply, code could be injected that skips the anticheat.
Of course, in their model, if a user isn’t given root privileges it seems much harder to do anything, then probably the first thing you’d want to look for is a privilege escalation attack to obtain root privileges. This might not be that hard if they for example run Xorg as it isn’t known to be the most secure - there’s a reason there’s a strong recommendation to not run any graphical UI on servers.
Another way if you don’t have root is to simply run the code on a system that does but that does have such a kernel module - or perhaps modify the binary itself to skip the anticheat. I don’t see anything preventing that in their scheme.
Here is the quote I paraphrased in my comment (I’m sure I got something wrong):
https://www.theverge.com/2024/3/19/24106356/playtron-explains-how-immutable-file-systems-are-not-but-could-help-with-linux-anti-cheat
Ah, so they don’t actually say that they read kernel space. They check the version of all installed packages and checksum the installed DLLs/SOs.
If the user still has root privileges, this may still not prevent sideloading of kernel modules. Even if it would detect a kernel module that has been sideloaded, I believe it’s possible to write a kernel module that will still be resident after you unload it. This kernel module can then basically do anything without the knowledge of userspace. It could for example easily replace any code running in userspace, and their anticheat would miss that as it doesn’t actually check what code is currently running. Most simply, code could be injected that skips the anticheat.
Of course, in their model, if a user isn’t given root privileges it seems much harder to do anything, then probably the first thing you’d want to look for is a privilege escalation attack to obtain root privileges. This might not be that hard if they for example run Xorg as it isn’t known to be the most secure - there’s a reason there’s a strong recommendation to not run any graphical UI on servers.
Another way if you don’t have root is to simply run the code on a system that does but that does have such a kernel module - or perhaps modify the binary itself to skip the anticheat. I don’t see anything preventing that in their scheme.