An attacker exploiting GPUhammer will shortly flip bits to which they’ve entry to as a way to have an effect on different reminiscence bits to which they don’t have entry, Ullrich defined. Nvidia recommends enabling ECC error correction, which can detect and probably forestall these unauthorized adjustments to reminiscence content material. ECC isn’t good, he mentioned, but when enabled will possible make the exploit much less sensible.
The assault additionally requires the attacker to execute particular code, he identified. That is extra of a risk to methods which can be shared between customers and permit totally different customers to have an effect on one another’s knowledge than single person methods, he mentioned.
The researchers’ paper states that a few of the abstractions of graphics playing cards make it a bit tougher to entry reminiscence to set off the Rowhammer exploit, he added. In contrast to DDR reminiscence linked to regular CPU buses, GPUs have a extra managed entry to reminiscence. “However in the long run,” he mentioned, “all Rowhammer wants is to shortly flip particular bits on and off, which continues to be attainable for GPUs. It simply takes extra work to determine which bits to flip, which is the primary contribution of the paper.”
