What is Rowhammer bit-flip attack which forced Nvidia to issue security alert

Time of India

16-07-2025

Researchers discovered that Nvidia's A6000 GPUs are prone to Rowhammer attacks. This allows hackers to tamper with user data on shared GPUs. Nvidia has issued an alert, advising users to enable Error Correction Code. Newer GPUs with GDDR7 or HBM3 memory have built-in protection. This vulnerability poses a risk in multi-tenant environments.
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What Is Rowhammer bit-flip attack
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Why is this a problem for Nvidia GPUs?
How did Nvidia respond?
A team of researchers has revealed that Nvidia's A6000 GPUs using GDDR6 memory are vulnerable to Rowhammer attacks, which can allow hackers to interfere with users' data on a shared GPU in the cloud, like AI models, even if they don't have direct access to it. In response to the research, Nvidia issued an alert for users asking them to ensure system-level ECC is enabled across the following NVIDIA products.'Specific generations of DRAM devices starting with DDR4, LPDDR5, HBM3, and GDDR7 implement On-Die ECC (OD-ECC) to help with DRAM scaling. OD-ECC indirectly protects Rowhammer bit flips. Note: OD-ECC is not adjustable by users. If OD-ECC is present, it is always enabled,' the company said in its alertRowhammer is a security issue where repeated access to memory can silently change data. Researchers just showed that this attack now works on Nvidia GPUs, so Nvidia issued an alert and recommends using ECC to stay safe.Rowhammer for GPUs, also called GPUHammer, is a new hardware attack that targets graphics cards, specifically NVIDIA GPUs with GDDR6 memory. It is a hardware vulnerability found in computer memory chips (DRAM).Normally, data is safely stored in separate rows of memory cells. But if you rapidly and repeatedly access (hammer) one row, it introduces bit flips in adjacent memory rows. This can 'flip' bits of data even if no one directly accessed that data.'Since 2014, this vulnerability has been widely studied in CPUs and CPU-based memories like DDR3, DDR4, and LPDDR4. However, with critical AI and ML workloads now running on discrete GPUs in the cloud, it is vital to assess the vulnerability of GPU memories to Rowhammer attacks,' the researchers said.Rowhammer is a circuit-level DRAM vulnerability that lets attackers flip bits in neighboring memory rows. It had only been shown on CPU DRAM before, but now, researchers have demonstrated the first Rowhammer bit-flip attack on GPU DRAM, specifically on GDDR6 memory used in NVIDIA GPUs like the A6000.Attackers can potentially use Rowhammer to mess with another user's data on a shared GPU in the cloud, like AI models, even if they don't have direct access to it. The research proved that even a single bit flip could destroy the accuracy of an AI model.The attack works in shared environments where multiple people or programs are using the same GPU at the same time (multi-tenant setups).Nvidia confirmed the Rowhammer risk on some GPUs and advised customers to turn on Error Correction Code (ECC), a memory feature that can catch and fix single-bit errors. This helps stop Rowhammer attacks, though it might slow down some AI workloads by up to 10%.Newer Nvidia GPUs (like those with GDDR7 or HBM3 memory) already have built-in protections (on-die ECC) against this type of attack.