Two Hidden Instructions Discovered in Intel CPUs Enable Microcode Modification

Two Hidden Instructions Discovered in Intel CPUs Enable Microcode Modification .
Security researchers Mark Ermolov, Dmitry Sklyarov, and Maxim Goryachy discovered two undocumented x86 instructions that can be used to modify the CPU microcode. The instructions can only be executed when the CPU runs in debug mode, which makes them not easily exploitable, though.

Read in full here:

This thread was posted by one of our members via one of our news source trackers.

3 Likes

Corresponding tweet for this thread:

Share link for this tweet.

2 Likes

Why does Intel keep having and adding so so so very many instructions that are undocumented in every form… It’s so horrible from a security standpoint (hence why so many theories that a lot of these are for exploitations) and it just complicates the chips even further. We need everything to switch to RISC-V or something, and keep it to the spec… >.>

2 Likes

Nothing would surprise me tbh, good job we got a #general-developer-forum:ethics-privacy section to keep tabs on stuff like this :nerd_face:

2 Likes

One more reason to go full AMD, assuming they don’t do the same of course…

2 Likes

AMD does also do the same because they have to stay compatible with Intel. Now thankfully they don’t go way way crazy extreme with it like intel does, but they have had to implement a certain subset of the functionality just to work. However, so far as far as I’ve heard there hasn’t been any big exploits of their stuff like there has been for Intel, repeatedly.

2 Likes

Well, maybe the prosaic reason is that nobody is talking about utilizing these exploits on AMD CPUs then?..

2 Likes