DEF CON 26 - Christopher Domas - GOD MODE UNLOCKED Hardware Backdoors in redacted x86
Why Hacker News recommends it
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.
What it is
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.
Recommended by 4 HN commenters across 3 different months, 2019 to 2026.
What Hacker News said
Strong rec daniel-thompson · 2021-08 · on “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.
Strong rec MattSteelblade · 2026-08 · on “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]
Recommends not1ofU · 2021-12 · on “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.
Recommends aecsocket · 2026-08 · on “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]
Cites kbenson · 2019-06 · on “Everybody Be Cool, This Is a Robbery”
While somewhat interesting, I'm not sure there's much to discuss unless the presentation or details are already available. Interestingly, this reminds me of two Defcon talks I watched in the last day or two, which also cover vulnerability through additional processors onboard.[1][2] 1: [this video] 2: [LINK]
Cites ddingus · 2021-02 · on “Dunfield 6809 Portable”
You are taking these ideas into crazy places! Fun to think about. Given this context, I have a few thoughts: Contemporary processors may be interesting when simplified some. Your projects make me think about the Zachtronics games. [LINK] That is an assembly language game with surprising depth. People, who play it seriously will learn quite a lot. Using older hardware in tandem with current is a lot of fun. The terminal, for example, still does exactly what it was designed to do and is still useful today. A C64 has a user port for this kind of thing. Apple 2 computers saw all manner of expansion cards capable of data capture, control, computation... making ones own card with a PIA was a stand
Cites corebuffer · 2021-05 · on “Alternate Instruction Set”
Related: a defcon talk about it (DEF CON 26 - Christopher Domas - GOD MODE UNLOCKED Hardware Backdoors in redacted x86) [this video] Website collecting info on thin clients, which many are VIA, if anyone gets interested in exploring it from a recycled unit: [LINK] EDIT: also [LINK] - Christopher Domas: Hardware Backdoors in X86 CPUs
Cites throwaway47292 · 2021-09 · on “Web-based editor”
haha maybe Christopher Domas knows :D [this video] [x86 god mode] but there is a difference between knowing vaguely how internal combustion engine works versus treating your car as a magic box from the future. (which of course now most cars are, you can not even disable the tire pressure alert after you pump your tires without going to the service shop) I fear that nobody will even teach the fetch-execute cycle to our kids.