GPUThor Rowhammer technique bypasses ECC on NVIDIA GPUs

Researchers from the University of Toronto have developed GPUThor, a Rowhammer attack that bypasses ECC protections on NVIDIA GPUs, achieving bit-flip rates thousands of times higher than previous methods. The attack targets Ampere-class GPUs with GDDR6 memory, including RTX A4000 to A6000 models, and can lead to denial-of-service or root privilege escalation. The technique uses non-uniform hammering patterns to avoid triggering GDDR6's Target Row Refresh mitigations.