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  • Some places do eventually listen. Crytek stealth dropped easy anticheat support for Hunt Showdown a few versions ago.

  • I am genuinely curious how anti-cheat works on an open source OS. I don't know a whole lot about how it works to be honest, but is there no problem with cheaters being able to manipulate the entire stack down to the kernel level?

    Like I'm aware cheaters can decompile code so closed source isn't necessarily that much better. Did I just answer my own question or is there more to it?

    • This is why client-side anti-cheat is a terrible idea. It gives you the illusion of control, but really it doesn't prevent a motivated party from cheating, and it opens up everyone else to kernel-level vulnerabilities when the anti-cheat software inevitably has a bug.

      Client side anti-cheat should merely discourage low effort attacks, and the real cheat detection should always be server side looking at patterns of behavior. Unfortunately, it's a lot easier to reach for client side anti-cheat than build an effective server side anti-cheat.

    • I'll do my best to explain:

      Firstly, not all code executed on an open source OS needs to be open source. For example: Epic Anti-Cheat, which comes with a Linux-compatible mode, is fully closed source. So right off the bat we're going to put to bed the notion that somehow the platform of choice makes it easier for bad actors to pull apart and examine anticheat software.

      Secondly, yes, there is a problem with cheaters being able to hide from anticheats on Linux. This is because on Windows it's relatively easy to run kernel-level code via drivers -- this is why most anticheats require admin permission to install a monitoring driver before the game will run. The anticheat is effectively rootkitting your system in order to circumvent other rootkits that may be concealing epic cheatz.

      On GNU/Linux, almost all device drivers come prepackaged in the Linux kernel, so there's no direct equivalent to the Windows approach of allowing users to install third-party code into the most protected rings of the OS. It's still possible through the use of kernel modules (see NVIDIA drivers), but as evidenced by how annoying it is to use NVIDIA devices on Linux, this is a huge PITA for both the developer & the user to deal with.

      So that's the rub. On Linux, anticheats just have to trust that the kernel isn't lying. This has been a perpetual thorn in the side of developers like Google, who'd really really like it if they could prove beyond a shadow of a doubt that a given Android device is not rooted (see SafetyNet). Google's solution to this has been to introduce hardware-backed attestation -- basically a special hardware chip on the device that can prove that the kernel software has not been tainted in any way.

      • I'm sure you agree with this, just wanted to add:

        It's also true that the ease with which a program can interact with kernel level drivers in Windows opens up a whole host of potential exploits including but not limited to recording all internet traffic, all keystrokes, listing all files & programs, accessing memory of other programs and more. AAA client-side anticheats require some pretty incredible trust in the vendor to not be either evil or incompetent.

      • This is because on Windows it's relatively easy to run kernel-level code via drivers

        Buuut there is nothing stopping a person from using virtualization.

      • Right so on a technical level it is actually harder to do client side anti-cheat?

        Thanks for the information. That hardware backed attestation reminds me of Little Brother by Cory Doctorow, where hardware DRM was introduced and then forcibly deprecated when it was found to be vulnerable... so of course the vulnerable hardware was now worthless except on the black market where it was worthwhile to pirates because it was known to be already cracked.

    • I am geniunely curious how anti-cheat works on an PC with physical access, where user can plug their mouse loaded with cheats.

      For every malware anti-cheat there will be sandboxing cheat.

      • That's a good point. I realise my question partly plays into a misconception about the security of closed source software, that it's somehow harder to mess with.

        I mean people are training neural nets to look at the screen and aimbot by modifying the mouse inputs, which is just an impossible thing to detect.

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