CVE-2024-37880: kyber — Exploit & Fix

Description

The Kyber reference implementation before 9b8d306, when compiled by LLVM Clang through 18.x with some common optimization options, has a timing side channel that allows attackers to recover an ML-KEM 512 secret key in minutes. This occurs because poly_frommsg in poly.c does not prevent Clang from emitting a vulnerable secret-dependent branch.

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CVSS v3.1 Score

7.5

HIGH

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

Weakness Type (CWE)

CWE-203 CWE-203

Affected Products

Vendor	Product	Versions
pq-crystals	kyber	< 2024-06-03

References

Advisories & Patches

https://github.com/pq-crystals/kyber/commit/9b8d30698a3e7449aeb34e62339d4176f11e3c6c https://github.com/pq-crystals/kyber/commit/9b8d30698a3e7449aeb34e62339d4176f11e3c6c

Exploits

https://github.com/antoonpurnal/clangover https://pqshield.com/pqshield-plugs-timing-leaks-in-kyber-ml-kem-to-improve-pqc-implementation-maturity/ https://twitter.com/purnaltoon/status/1797644696568959476 https://github.com/antoonpurnal/clangover https://pqshield.com/pqshield-plugs-timing-leaks-in-kyber-ml-kem-to-improve-pqc-implementation-maturity/ https://twitter.com/purnaltoon/status/1797644696568959476

Other References

https://news.ycombinator.com/item?id=40577486 https://news.ycombinator.com/item?id=40577486

Frequently Asked Questions

What is CVE-2024-37880? +

The Kyber reference implementation before 9b8d306, when compiled by LLVM Clang through 18.x with some common optimization options, has a timing side channel that allows attackers to recover an ML-KEM 512 secret key in minutes. This occurs because poly_frommsg in poly.c does not prevent Clang from emitting a vulnerable secret-dependent branch. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2024-37880? +

CVE-2024-37880 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2024-37880? +

CVE-2024-37880 affects products from pq-crystals, specifically: kyber. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-37880? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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