Academic researchers developed ZenHammer, the first variant of the Rowhammer DRAM attack that works on CPUs based on recent AMD Zen microarchitecture that map physical addresses on DDR4 and DDR5 memory chips.
So they basically discovered how to do an exploit that was done on other chips but was previously considered unlikely on AMD chips.
Jesus_666@feddit.de 3 months ago
Note that as per the paper DDR5 is a lot harder to attack than DDR4 so newer systems should be less vulnerable (but not entirely immune).
Tobberone@lemm.ee 3 months ago
And unlike the rowhammer report which came a few years ago, neither AM4 nor AM5 is reported at 100% success rate, which asks the question why? What made those specific systems vulnerable?
Jesus_666@feddit.de 3 months ago
It might just come down to timing issues. They did mention that one reason DDR5 is so hard to attack is that the time window for flipping a bit is impractically short.