'Super-secret' Password-protected Debugger Discovered in AMD Processors

A hardware hacker has discovered a secret debugging feature hidden in all AMD chips made in the past decade. "The password-protected debugger came as a shock to reverse-engineers who've hungered for an on-chip mechanism for performing conditional and direct-hardware breakpoint operations. Although AMD has built the firmware-controlled feature into all chips since the Athlon XP, […]

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A hardware hacker has discovered a secret debugging feature hidden in all AMD chips made in the past decade. "The password-protected debugger came as a shock to reverse-engineers who've hungered for an on-chip mechanism for performing conditional and direct-hardware breakpoint operations. Although AMD has built the firmware-controlled feature into all chips since the Athlon XP, the company kept it a closely guarded secret that was only disclosed by a hacker who goes by the name Czernobyl."

"AMD processors (Athlon XP and better) have included firmware-based debugging features that expand greatly over standard, architecturally defined capabilities of x86," the hacker wrote. "For some reason, though, AMD has been tightly secretive about these features; hint of their existence was gained by glancing at CBID's page."

To put a chip into developer mode, a user must first enter what amounts to a password -- 9C5A203A -- into the CPU's EDI register. Czernobyl was able to deduce the secret setting by brute forcing the key.

[Source]

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Deepak Gupta is a IT & Web Consultant. He is the founder and CEO of diTii.com & DIT Technologies, where he’s engaged in providing Technology Consultancy, Design and Development of Desktop, Web and Mobile applications using various tools and softwares. Sign-up for the Email for daily updates. Google+ Profile.