critical
9
CWE
20
Advisory Published
Updated

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

First published: Tue Nov 16 2021(Updated: )

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.

Credit: vulnerability@ncsc.ch vulnerability@ncsc.ch

Affected SoftwareAffected VersionHow to fix
All of
Samsung DDR4 RAM
Samsung DDR4 RAM
All of
Samsung Lddr4 Firmware
Samsung LPDDR4
All of
Micron LDDR4 Firmware
Micron LPDDR4
All of
Micron LDDR4 Firmware
Micron DDR4 SDRAM Firmware
All of
Skhynix DDR4 SDRAM Firmware
Skhynix DDR4 SDRAM Firmware
All of
Skhynix LPDDR4 Firmware
Skhynix LPDDR4
Samsung DDR4 RAM
Samsung DDR4 RAM
Samsung Lddr4 Firmware
Samsung LPDDR4
Micron LDDR4 Firmware
Micron LPDDR4
Micron LDDR4 Firmware
Micron DDR4 SDRAM Firmware
Skhynix DDR4 SDRAM Firmware
Skhynix DDR4 SDRAM Firmware
Skhynix LPDDR4 Firmware
Skhynix LPDDR4

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2021-42114?

    CVE-2021-42114 is a high-severity vulnerability affecting certain DRAM devices due to their inadequate Target Row Refresh (TRR) mechanism.

  • How do I fix CVE-2021-42114?

    To mitigate CVE-2021-42114, manufacturers should provide firmware updates to improve the TRR mechanisms in affected memory devices.

  • Which devices are affected by CVE-2021-42114?

    CVE-2021-42114 impacts modern DRAM devices, particularly PC-DDR4 and LPDDR4X from manufacturers such as Samsung, Micron, and Skhynix.

  • What is the nature of the attack associated with CVE-2021-42114?

    CVE-2021-42114 involves Rowhammer attacks that exploit non-uniform access patterns to trigger vulnerabilities in the memory's TRR.

  • Can CVE-2021-42114 be exploited remotely?

    CVE-2021-42114 requires physical access or specific conditions to exploit the vulnerability, making remote exploitation less likely.

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