Observable Timing Discrepancy in pypqc

published 2024-06-05 2y ago modified 2024-12-02 last yr.

cvss: 8.2; version 3.1, GitHub
cisa kev: Not listed; not in CISA's catalog
epss: —; no score, EPSS covers CVEs only
public exploits: 0; none known

### Impact `kyber512`, `kyber768`, and `kyber1024` on Mac OS \(or when compiled with clang\) only: An attacker able to submit many decapsulation requests against a single private key, and to gain timing information about the decapsulation, could recover the private key. Proof-of-concept exploit exists for a local attacker.

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

### Patches No patch is currently available / pending upstream [PQClean#556](https://github.com/PQClean/PQClean/issues/556).

### Workarounds No workarounds have been reported. The 0.0.7 -> 0.0.7.1 upgrade, when available, should be a drop-in replacement.

### References

https://pqshield.com/pqshield-plugs-timing-leaks-in-kyber-ml-kem-to-improve-pqc-implementation-maturity/

https://github.com/antoonpurnal/clangover

https://www.github.com/PQClean/PQClean/issues/556

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

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CVSS scores

assigned by	version	score	vector
GitHub	3.1	8.2	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N/E:P/RL:U/RC:C

Affected packages

ecosystem	package	affected	fixed in
pypi	pypqc	>=0.0.4, <=0.0.6.2	no fix listed

Classification

Weakness

CWE-385 Covert Timing Channel
CWE-733 Compiler Optimization Removal or Modification of Security-critical Code

References

Sources

GitHub Advisory GHSA-hvh4-5qr6-3v7r

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