Domas: Bypassing memory protection with AMD's memory controllers

Security researcher Christopher Domas published a proof of concept showing how AMD memory controllers' bank swizzle mode can be exploited to bypass memory protection, enabling arbitrary reads and writes including CPU microcode definitions and platform security processor memory. This lets kernel-level code manipulate the meaning of processor instructions, potentially undermining memory encryption and virtual machine isolation. The behavior is documented in AMD's manual, but using it to rewrite supposedly immutable firmware without crashing the machine appears to be an unintended consequence of the design. Exploitation requires kernel-level privileges, limiting immediate risk, though the technique could eventually be weaponized.

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