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DEF CON 26 - Christopher Domas - GOD MODE UNLOCKED Hardware Backdoors in redacted x86

DEFCONConference4 HN recommenders · recommended in 3 months, 2019–2026
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talk · advanced · evergreen · 2019–2026 on HN

Christopher Domas presents research at DEF CON 26 showing a hidden alternate instruction set and undocumented hardware backdoor in some x86 processors, found on a third-party CPU. He uses it to ask how feasible wider hardware backdoors are.

HN regulars treat Domas as a favorite hacker and bring this talk up in any discussion of CPU backdoors, hidden instruction sets or processor security.

10 comments from Hacker News

@MattSteelblade2026-08 · in “Spaghettifying DRAM”

I cannot wait for the accompanying Black Hat talk. Christopher Domas is one of my absolute favorite all-time hackers. He does such a fantastic job of explaining his work. Some of my favorite talks of his: - Psychological Warfare in Reverse Engineering link - The MoVfuscator link - Hardware Backdoors in redacted x86 ▶ this video

Strongly recommends View on HN
@daniel-thompson2021-08 · in “Compiling C Programs Into “Mov” Instructions (And Only “Mov” Instructions)”

These links don't work for me, but the videos are on YT: - ▶ this video - link And yes, they are spectacular.

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@aecsocket2026-08 · in “Spaghettifying DRAM”

Holy shit, Christopher Domas is back. I remember watching his Defcon talks on x86 shenanigans[^1][^2] and being amazed at what he's been able to discover. Then he got whisked away by Intel and now drops this. I'm excited. [^1]: link [^2]: ▶ this video

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@not1ofU2021-12 · in “Intel updates mysterious ‘software-defined silicon’ code in the Linux kernel”

This guy now works for intel: DEF CON 26 - Christopher Domas - GOD MODE UNLOCKED Hardware Backdoors in redacted x86 ▶ this video This is one of many amazing videos this guy did before they hired him.

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@LinuxBender2022-08 · in “Ask HN: Do you worry about CPU backdoors like IME?”

What are the implications of such hardware on user security? Threat persistence, i.e. persistent rootkits, persistent remote monitoring if one has privs to tickle the CPU instructions that give access. It is just a matter of time before there are public tools for script kiddies to manage the OS within the CPU. Here [1] is an example of someone slowly making progress decoding all the undocumented instructions and here is a talk with a brief overview of the tools. [2] This is not specific to Intel's ME but it is the way people will eventually tame/exploit that beast in my opinion. There are more recent talks that get deeper into security rings in the CPU. This video [3] more related to your question but not specific to ME however can be used to access ME and much more. If this appears to difficult and time consuming just know that some folks out there have the documentation for the undocumented instructions. You may find some tools on github and other public repos for disabling ME. Use with care. Test on an identical model of system that is at the same firmware/BIOS and same model of CPU as those tools can brick your CPU. As @rocket_surgeron stated, one can buy CPU's with ME disabled but that will not disable the "God Mode" referenced in [3]. [1] - link [2] - link [3] - ▶ this video