CVE-2021-42114 – Scalable Rowhammering In the Frequency Domain to Bypass TRR Mitigations On Modern DDR4/LPDDR4X Devices

https://notcve.org/view.php?id=CVE-2021-42114

Modern DRAM devices (PC-DDR4, LPDDR4X) are affected by a vulnerability in their internal Target Row Refresh (TRR) mitigation against Rowhammer attacks. Novel non-uniform Rowhammer access patterns, consisting of aggressors with different frequencies, phases, and amplitudes allow triggering bit flips on affected memory modules using our Blacksmith fuzzer. The patterns generated by Blacksmith were able to trigger bitflips on all 40 PC-DDR4 DRAM devices in our test pool, which cover the three major DRAM manufacturers: Samsung, SK Hynix, and Micron. This means that, even when chips advertised as Rowhammer-free are used, attackers may still be able to exploit Rowhammer. For example, this enables privilege-escalation attacks against the kernel or binaries such as the sudo binary, and also triggering bit flips in RSA-2048 keys (e.g., SSH keys) to gain cross-tenant virtual-machine access. • https://comsec.ethz.ch/research/dram/blacksmith https://comsec.ethz.ch/wp-content/files/blacksmith_sp22.pdf https://github.com/comsec-group/blacksmith • CWE-20: Improper Input Validation •