GPUThor: Rowhammer Attack Bypasses ECC on NVIDIA RTX A-Series GPUs
University of Toronto researchers have demonstrated GPUThor, a sophisticated Rowhammer-based attack targeting GDDR6 memory architectures in NVIDIA Ampere workstation GPUs, specifically the RTX A4000 through A6000 series. By utilizing non-uniform row hammering patterns, the exploit induces multi-bit flips—specifically double and triple bit errors—that exceed the correction capabilities of standard Error Correction Code (ECC) mechanisms. This bypass allows an attacker to corrupt memory page tables, facilitating a transition from unprivileged program execution to host-level root shell access. The attack demonstrates a massive increase in efficiency, reducing exploit time from nearly 22 hours to approximately 1.1 minutes, posing a significant risk to multi-tenant AI/ML cloud environments and high-performance workstations.