Hardware backdoors in some x86 CPUs

Post by dgellow » Sat, Aug 08, 2026, 2:14 PM UTC

rkagerer wrote: post #52

saidnooneever wrote: post #2

this is pretty old by now but still very relevant. people dont look at this enough but with rising chip complexities for TPU units etc. and a shift towards poorly documented hardware like NVIDIA gives this problem new fuel. Domas (and maybe his team or colleagues?) has put out shit tons of very interesting materials over the past years on advanced malware, implants and things like Cantor Dust which are amazing things…

I didn't know what Cantor Dust was, and had to click through a few different search results to get past all the abstract descriptions and begin to form a basic idea. In a nutshell, I understand them as a sort of "blockie" for binary data formats. Things like WAV audio files, bitmaps, ASCII text, machine code, etc. each generate their own distinct visual signature (but different examples within any of these categories…

Post by JacobKfromIRC » Sat, Aug 08, 2026, 2:28 PM UTC

close04 wrote: post #31

blank429384jf wrote: post #30

Earlier quoted context omitted.

backdoor means a secondary access point that defeats the security features of the primary. In the door analogy, the home owner spends a ton on a lock and camera for the front door but doesn't even have a deadbolt on the back.

Every definition of a “backdoor” in computing implicitly or explicitly considers it hidden/covert. In the house analogy you don’t see the backdoor when approaching the front. If it was just “an alternative everyone knows about and can be broken easier than the front door” then it probably would have been called “a window”. Most login forms have a weaker option like a SMS 2FA or password reset fallback. Nobody calls i…

Post by hnuser123456 » Sat, Aug 08, 2026, 2:32 PM UTC

K0balt wrote: post #62

joss82 wrote: post #6

This backdoor only appears on decades-old VIA C3 embedded x86 processors

TBF the specific backdoor isn’t the point of the article. It’s a cautionary tale. The point is that practically all systems above the MCU level, and even some of those, have lower level systems that are often undocumented or not intended for use by the hardware designers, much less the end users. Those systems often have extremely low level access to system resources. For example, I am building a device that records…

Post by wbsun » Sat, Aug 08, 2026, 2:39 PM UTC

Post by fsflover » Sat, Aug 08, 2026, 2:45 PM UTC

Zigurd wrote: post #57

amelius wrote: post #55

Earlier quoted context omitted.

If many people do this then I'm sure China will find some uses for that data at some point.

Sure but the cops aren't going to pull you over based on what you think about Chinese policy. Government do mess with people across international borders, but the capacity to do that is inherently limited.