Christopher Domas

AMD Memory Controller PoC Bypasses Hardware Isolation on Family 16h Processors

Security researcher Christopher Domas released a proof-of-concept project named skitter-creek-bath-salts that demonstrates a bypass of hardware memory protections on AMD Family 16h processors. The technique manipulates DRAM controller settings to access regions that should remain inaccessible even to the operating system, kernel, and ring-0 code. By altering a single register after upstream protections have acted, the controller remaps addresses, creating an alias that leads to the same DRAM cells through an alternative path. The PoC uses linear algebra and the Z3 SMT solver to locate alias addresses and carefully manages interrupts, cache, and page tables to avoid system crashes during the brief remapping window. Demonstrations include potential access to the AMD Platform Security Processor, fTPM data, System Management Mode regions, C6 processor states, and microcode storage, with the possibility of modifying microcode patches. The research was validated only on AMD Family 16h; no similar issues have been reported for newer AMD, Intel, ARM, or RISC-V platforms.