Comment by 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...
> 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.
> 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
> 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
I can assure you that you will get banned from a game with a modern anti-cheat using that or you won't even be able to launch the game. Also 'flagged by most anti-cheats' means very little. Most good anti-cheats will delay bans or correlate multiple factors prior to a ban.
> You are going to have to decrypt the memory eventually. Even TEE.fail can get around AMD SEV and Intel's TEE.
You don't have to decrypt it on the RAM wire bus. And the reasons TEE.fail is successful is because they screwed up the crypto as far as I can tell.
> Once you can intercept network traffic and decrypt its game over!
Not sure why you are so hung up on this. You still need to access the memory first. That's what they will detect and prevent. They obviously can't prevent or detect network sniffing if the key is known.
> 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
I've made FPGA designs previously, including custom PCIE DMA cards back in ~2018. It would surprise me if you could find an FPGA capable of reliably sniffing DDDR5 6000+ MT/S without crashing the host system. FPGAs are not nearly as fast as CPUs. Maybe you could somehow hack a FPGA DDR memory interface. But finding one fast enough for DDR5 is probably impossible (or terribly expensive). Maybe https://www.amd.com/en/products/adaptive-socs-and-fpgas/vers... is theoretically possible. But you are looking at a 10k+ chip, if not 20k$+. Such a chip is not going to be easily embeddable and likely requires 10s if not 100s of amps of power delivery.
There are DDR4 interposers you can buy for 50$. The basic thing is that you don't need all of the ram all of the time, you just need to find an address which you can then rewrite to make two valid references to the same physical memory (see: badRAM/battering ram). Then you can use an IOMMU compliant DMA to access that memory.
Or you can use an FPGA to interpose the RAM and intercept the network traffic for a couple hundred bucks.
You can still do DMA cheating with IOMMU enabled. There are quite a few relatively widespread bugs with IOMMU that allow you to bypass it, for example https://cloud.google.com/blog/products/gcp/fuzzing-pci-expre.... So to be able to actually do IOMMU DMA protection you need to be willing to ban many popular devices. That may be viable for FACEIT and ESEA but it won't be for 99.9% of anticheat deployments.
The detection for DMA cheating is based on the DMA engines being unable to emulate 1:1 the actual behavior the hardware ID would be expected to have. This can be fixed by simply doing that properly.
But even besides that, DMA through PCIe is just one hardware cheat that fits a separate thread model and therefore has some countermeasures.
There are much more robust methods you can use, for example a PCIe interposer between the OS and GPU, or simply direct memory interposes if you want to do DMA without the protections afforded by the PCIe implementation. There are interposets along with machinery to get along memory encryption and other obfuscations that can be made for around 100$.
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