Secret debug mode hacked in AMD processors


A hidden debugging mode discovered by a hacker, hardwired into all AMD processors starting with the Athlon XP, significantly expands the debugging capabilities, taking it beyond the x86 architecture specifications.

Opened by a hacker known as Czernobyl, debug mode appears to be an internal AMD utility supported at the processor architecture level but disabled at release. Despite the presence of this feature, it can only be accessed by setting certain values in the processor registers - values \u200b\u200bwhich, like passwords, AMD keeps in the strictest confidence.

Czernobyl, however, cracked the security and got to the debug module, opening up huge possibilities that could make AMD processors the choice for hackers, coders, and especially reverse engineers.

The hacker describes his work documenting the activation and using the hardware debugging mechanism as "Work in progress, but ready to use - released as is". However, it is not for cowards. An unsuccessful attempt to enter the required code into the processor registers will lead to an error in the protection system, and as a result, the system will crash, which is not very pleasant in the process of reverse engineering some intricate code.

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