Secret-key recovery via compiler-induced timing branch
Published Jun 10, 2024 · Updated Aug 2, 2024
Timing side channel in the CRYSTALS Kyber reference implementation before 9b8d306 allows attackers to recover ML-KEM 512 secret keys. The poly_frommsg function converts secret message bits into polynomial coefficients, but Clang 15 through 18 can optimize its constant-time selection into a secret-dependent branch. Exposure requires an x86 build made with affected optimization options and enough decapsulation timing measurements; the demonstrated attack recovers the entire key in about 5 to 10 minutes.
Summary
What happened
Timing side channel in the CRYSTALS Kyber reference implementation before 9b8d306 allows attackers to recover ML-KEM 512 secret keys. The poly_frommsg function converts secret message bits into polynomial coefficients, but Clang 15 through 18 can optimize its constant-time selection into a secret-dependent branch. Exposure requires an x86 build made with affected optimization options and enough decapsulation timing measurements; the demonstrated attack recovers the entire key in about 5 to 10 minutes.
The record
- CVE
- CVE-2024-37880
- Published
- Jun 10, 2024
- Updated
- Aug 2, 2024
- Vendor
- CRYSTALS
- Product
- Kyber
- Classifications
- CWE-203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 10, 2024CVE publishedPublication date reported by the CVE source.
- Aug 2, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <2024-06-03
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- clangover ML-KEM 512 key-recovery proof of conceptfunctional · demonstrated
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Technologies
Your stack
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Your stack
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