Hackers Take Control of Nvidia GPUs with Novel Rowhammer Attacks

Nvidia GPUs, costing upwards of $8,000, are frequently shared among dozens of users in cloud environments due to their high performance. However, two new Rowhammer attacks have demonstrated how a malicious user can gain complete root control of the host machine by exploiting memory hardware vulnerabilities in these powerful GPU cards.

The Rowhammer technique, first discovered in 2014, takes advantage of the increasing susceptibility of DRAM memory to bit flips, where stored 0s switch to 1s and vice versa. Repeated, rapid access, or "hammering," of DRAM hardware creates electrical disturbances that can flip these bits. Later research showed that by targeting specific DRAM rows storing sensitive data, an attacker could exploit bit flips to escalate an unprivileged user to root access or bypass security sandbox protections.

Over the past decade, Rowhammer attacks have evolved to target various hardware, including CPUs. These new attacks now extend the vulnerability to Nvidia GPUs, allowing malicious users to gain complete control of the host machine.

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The implications of these attacks are significant, particularly in cloud environments where high-performance GPUs are shared among multiple users. A malicious user could potentially exploit the Rowhammer vulnerability to gain administrative access and compromise the entire system, posing a serious security risk.

Researchers have already demonstrated two novel Rowhammer attack techniques that target Nvidia GPUs. The first attack, dubbed "GuardION," exploits the GPU's memory management system to bypass security protections and flip bits in the system's memory. The second attack, "MemJam," leverages the GPU's memory access patterns to induce bit flips, ultimately granting the attacker root-level control.

These attacks highlight the ongoing challenge of securing shared computing resources, particularly as hardware vulnerabilities like Rowhammer continue to evolve. Nvidia and other hardware manufacturers will need to work diligently to address these vulnerabilities and protect users from potential exploitation.

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In the meantime, cloud service providers and users of high-performance Nvidia GPUs should remain vigilant and implement robust security measures to mitigate the risks posed by these new Rowhammer attacks. The battle against hardware-based vulnerabilities is far from over, and continued research and innovation will be necessary to stay ahead of the evolving threat landscape.