Comment by bflesch

Comment by bflesch 2 days ago

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Kernel anticheat is not really effective because it can be circumvented on the hardware level, for example using direct memory access with a second computer and screen to show the hidden game state.

Cheating is a meat space problem and there is no technical solution to it. Thats why in tournaments there are referees standing behind the players. Ultimately it comes down to checking if metrics like reaction speed are humanly possible, but a rootkit is not really needed for that.

maccard 2 days ago

> Cheating is a meat space problem and there is no technical solution to it

Cheating is an arms race - the number of people who are willing to run a second computer with DMA connected to a single machine is vastly smaller than the number of people who are wiling to download a dodgy file from the internet and run it.

> Ultimately it comes down to checking if metrics like reaction speed are humanly possible, but a rootkit is not really needed for that.

If it was that easy, cheating would be a solved problem. An awful lot of play is "I know the reload time is 0.75s, so they're going to appear when they've reloaded" - that's way beyond human reaction time. And that's at "mid level" play - at gold/sliver levels in league of legends knowing cooldowns is considered base knowledge. At higher levels of play, _all_ of your players are statistical outliers.

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  • sudosysgen 10 hours ago

    This hasn't been true for a very long time. The kind of cheats that can survive even very basic anticheat for a long time cost a decent amount of money on subscription basis. Most cheaters by volume pay quite a chunk of change to cheat.

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bangaladore 2 days ago

> Kernel anticheat is not really effective because it can be circumvented on the hardware level, for example using direct memory access with a second computer and screen to show the hidden game state.

Incorrect. DMA (direct memory access) is and can be prevented [1] and detected [2].

[1] https://www.faceit.com/en/news/faceit-rollout-of-tpm-secure-...

[2] https://community.osr.com/t/detecting-pcie-dma-based-cheatin...

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  • vablings a day ago

    Once again back to another arms race. Assuming that your operating system doesn't allow any bad drivers (Windows does NOT do this) physical access to the hardware is just a function of time and money to get direct access to the memory

    https://x.com/danielgenkin/status/1989003973429268974?s=12

    Something like TEE.fail can be used to read encryption keys for network traffic then a MITM proxy can display player information easily on a second PC, you will never be able to reliably detect this

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    • bangaladore 20 hours ago

      > Assuming that your operating system doesn't allow any bad drivers (Windows does NOT do this)

      Windows eventually tends to revoke the certificate of vulnerable drivers. And prior to that, anti-cheats will flag the signature and prevent booting or outright ban for egregious ones.

      > Something like TEE.fail can be used to read encryption keys for network traffic

      So, encrypt the memory well then? Also, that attack slows down RAM to 3200 MT/S and is infeasible for game cheating. Maybe if you could make a custom ram stick with an ASIC on it, which would cost millions on millions of dollars to keep up with DDR5, you could capture encrypted bits and crash your system pretty often.

      I don't consider it an arms race if you can prevent cheating to 10s of people in a million-player game. That's noise at best.

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      • vablings 19 hours ago

        > Windows eventually tends to revoke the certificate of vulnerable drivers. And prior to that, anti-cheats will flag the signature and prevent booting or outright ban for egregious ones.

        I have been loading and using the WinIO driver on windows all the way up to the latest version to read and write any memory I want. I also have a few drivers that are lesser known that are not even flagged by most anti-cheats

        > So, encrypt the memory well then? Also, that attack slows down RAM to 3200 MT/S and is infeasible for game cheating. Maybe if you could make a custom ram stick with an ASIC on it, which would cost millions on millions of dollars to keep up with DDR5, you could capture encrypted bits and crash your system pretty often.

        You are going to have to decrypt the memory eventually. Even TEE.fail can get around AMD SEV and Intel's TEE. Reading memory speed doesn't really matter as long as you can find an encryption key for network traffic. Once you can intercept network traffic and decrypt its game over!

        You do not need an ASIC to interpose DDR5 and steal all the traffic, there are FPGAs that are powerful enough. Once PCIE DMA cards go the way of the dino with IOMMU people will just switch to memory interposers with FPGAs

        A few years ago, DMA cards cost upwards of $500. Now you can buy cards from china preloaded with pcieleech firmware for around $100. and there are thousands of customers. If you can afford the latest gen gaming gear and afford to spend money on cheats you can certainly fork over a couple hundred dollars for the latest undetected solution

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      • sudosysgen 10 hours ago

        There are DDR4 interposers you can buy for 50$. The basic thing is that you don't need all of the ram all of the time, you just need to find an address which you can then rewrite to make two valid references to the same physical memory (see: badRAM/battering ram). Then you can use an IOMMU compliant DMA to access that memory.

        Or you can use an FPGA to interpose the RAM and intercept the network traffic for a couple hundred bucks.

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  • sudosysgen a day ago

    You can still do DMA cheating with IOMMU enabled. There are quite a few relatively widespread bugs with IOMMU that allow you to bypass it, for example https://cloud.google.com/blog/products/gcp/fuzzing-pci-expre.... So to be able to actually do IOMMU DMA protection you need to be willing to ban many popular devices. That may be viable for FACEIT and ESEA but it won't be for 99.9% of anticheat deployments.

    The detection for DMA cheating is based on the DMA engines being unable to emulate 1:1 the actual behavior the hardware ID would be expected to have. This can be fixed by simply doing that properly.

    But even besides that, DMA through PCIe is just one hardware cheat that fits a separate thread model and therefore has some countermeasures.

    There are much more robust methods you can use, for example a PCIe interposer between the OS and GPU, or simply direct memory interposes if you want to do DMA without the protections afforded by the PCIe implementation. There are interposets along with machinery to get along memory encryption and other obfuscations that can be made for around 100$.

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cortesoft 2 days ago

This is theoretically possible, but I don't think most cheaters would have the equipment or skill to do this. Cheating is only rampant in games where people can just buy and download cheats... if it requires a lot of skill and hardware, it won't be a big issue.

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  • sudosysgen a day ago

    It's not just theoretically possible, you can buy kits that do this already.

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