CVE-2021-42114 Information

Description

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. We can confirm that DRAM devices acquired in July 2020 with DRAM chips from all three major DRAM vendors (Samsung SK Hynix Micron) are affected by this vulnerability. For more details please refer to our publication.

CVSS Vector

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Reference

https://github.com/comsec-group/blacksmith https://comsec.ethz.ch/research/dram/blacksmith/ https://comsec.ethz.ch/wp-content/files/blacksmith_sp22.pdf

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

CHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.3