New Rowhammer attacks give complete control of machines running Nvidia GPUs - Ars Technica

Text settings Story text Size Small Standard Large Width * Standard Wide Links Standard Orange * Subscribers only   Learn more Minimize to nav The cost of high-performance GPUs, typically $8,000 or more, means they are frequently shared among dozens of users in cloud environments. Two new attacks demonstrate how a malicious user can gain full root control of a host machine by performing novel Rowhammer attacks on high-performance GPU cards made by Nvidia. The attacks exploit memory hardware’s increasing susceptibility to bit flips, in which 0s stored in memory switch to 1s and vice versa. In 2014, researchers first demonstrated that repeated, rapid access—or “hammering”—of memory hardware known as DRAM creates electrical disturbances that flip bits. A year later, a different research team showed that by targeting specific DRAM rows storing sensitive data, an attacker could exploit the phenomenon to escalate an unprivileged user to root or evade security sandbox protections. Both attacks targeted DDR3 generations of DRAM. From CPU to GPU: Rowhammer’s decade-long journey Over the past decade, dozens of newer Rowhammer attacks have evolved to, among other things: Target a wider range of DRAM types, such as DDR3 with error correcting code protections and DDR4 generations, including those with Target Row Refresh and ECC protections Use new hammering techniques, such as Rowhammer feng shui and RowPress that zero in on extremely small regions of memory storing sensitive data Use ...