GPUThor Rowhammer Attack Corrupts GDDR6 Memory on NVIDIA Ampere GPUs

University of Toronto researchers described GPUThor, a Rowhammer-class attack targeting GDDR6 memory in NVIDIA Ampere GPU accelerators. The technique characterizes the platform’s Targeted Refresh Rate (TRR) behavior and uses non-uniform memory-access patterns to induce substantially more bit flips than earlier GPU Rowhammer methods, extending the DRAM disturbance-error threat first established by Rowhammer research.

GPUThor generated double- and triple-bit memory corruptions, which can exceed ECC’s single-bit correction capability. Researchers demonstrated a denial-of-service outcome: a GPU reset accompanied by data loss and a hardware-replacement warning. They did not demonstrate arbitrary code execution or compromise newer GPU generations; ECC bypass leading to code execution remains theoretical.