Novel Rowhammer attack bypasses DRAM chip protections

The Hacker News reports that researchers at Qualcomm Technologies, ETH Zurich and Vrije Universiteit Amsterdam have discovered a new Rowhammer attack technique dubbed "Blacksmith," which could avoid established protections in all dynamic random-access memory chips. Blacksmith leverages "non-uniform and frequency-based" memory access patterns to prompt bit flips on all DRAM devices, according to researchers. Researchers found that while an in-memory defense mechanism dubbed "Target Row Refresh" has been included in DRAM modules to avert Rowhammer, it has not been sufficient to thwart Blacksmith attacks and other Rowhammer attacks. Forty DDR4 devices from Samsung, SK Hynix and Micron were found to have one or more patterns prompting Rowhammer bit errors from the attacks. "The tendency in DRAM manufacturing is to make the chips denser to pack more memory in the same size which inevitably results in increased interdependency between memory cells, making Rowhammer an ongoing problem," said Google's open-source research team.