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Breaking the x86 Instruction Set

Black Hat · 381.2K views · 2017-08-31 · 44:29

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Overview

Christopher Domas presents at Black Hat 2017 how page fault analysis and processor fuzzing can exhaustively search the x86 instruction set. The talk uncovers undocumented instructions and hardware bugs and shows limits of disassemblers.

On Hacker News

HN recommends it as a clever, entertaining and easy-to-follow talk on finding hidden x86 instructions with the Sandsifter tool.

Recommended by 9 HN people across 8 months · HN mentions 2017–2022

Topics

Security & hackingComputer architecture & CPUs
Search by tags
x86fuzzingsandsifterdisassemblerscpu securityreverse engineering

What people said

brokenmachine · 2021-07 · Recommendation

I watched a super interesting Black Hat video on youtube that talked about discovering secret instructions on CPUs by iterating over each bit of opcodes until you get an illegal instruction, and thereby discovering if an opcode is valid or not. He set up a room full of PCs running his code and had hardware to auto-reset them when they crashed. [VIDEO]

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gbrown_ · 2021-04 · Recommendation

How about undocumented instructions? Sandsifter[1] is an interesting project and the video from BlackHat[2] is a good watch. There's also a previous discussion of it on HN[3]. [1] [LINK] [2] [VIDEO] [3] [LINK]

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BlackLotus89 · 2021-03 · Recommendation

There was an interesting black hat talk about automatically finding undocumented instructions. [0] Interesting comment on twitter to the instruction of the original post[1] [0] [VIDEO] [1] [LINK]

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Sources

Video by Black Hat, played through YouTube.

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