Processors via c3 can be violated with a simple shell command

VIA C3 processors probably constitute a tiny amount of the market share of the desktop PC, and their manufacturers market the chip only in pre-assembled equipment such as digital signage booths, information booths, ticket vending machines, ATMs, etc.. (they don't need much processing power).

Accessing root privileges in Linux on a VIA C3 CPU machine is very easy

At the Black Hat 2018 conference, security researcher Christopher Domas found that accessing root privileges on Linux on a machine with VIA C3 “Nehemiah” processors is ridiculously easy. Just type ".byte 0x0f, 0x3f" (without quotes) into any Linux CLI in user mode, and voila! You are now the root user of that system. ”

Domas calls this his own iddqd (the cheat code for "God Mode" in "Doom"). This backdoor, likely placed by the processor's own designers, completely collapses the operating system's ring-based privilege system and elevates users and applications from ring-2 (and above) user space to ring 0 (root). It is an exploitation of a shadow-core, a hidden RISC processor within C7, which manages the startup, operation, and key storage of x86 cores. Intel and AMD also have shadow-cores with similar functions.

That's how easy it would be to be a root user in Linux under a VIA C3 processor, demonstrating how vulnerable it could be to manipulate the computers that come with this kind of chips, the challenge would be to first access the machines and computers that run it, that's another history.

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