Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS14NWoyLWc2M20tZjhnNM4AA5MK

pqc_kyber KyberSlash: division timings depending on secrets

Various Kyber software libraries in various environments leak secret information into timing, specifically because

• these libraries include a line of code that divides a secret numerator by a public denominator,
• the number of CPU cycles for division in various environments varies depending on the inputs to the division, and
• this variation appears within the range of numerators used in these libraries.

The KyberSlash pages track which Kyber libraries have this issue, and include a FAQ about the issue.

Author

The KyberSlash pages were written by Daniel J. Bernstein. The FAQ originally said "I", but some people seemed to have trouble finding this authorship statement, so the FAQ now says "Bernstein" instead.

URL

The permanent link for the KyberSlash pages is https://kyberslash.cr.yp.to.

Mitigation status in pqc_kyber crate

The issues has not been resolved in the pqc_kyber crate. A third-party fork that mitigates this attack vector has been published as safe_pqc_kyber.

Permalink: https://github.com/advisories/GHSA-x5j2-g63m-f8g4
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS14NWoyLWc2M20tZjhnNM4AA5MK
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: 3 months ago
Updated: 18 days ago

CVSS Score: 7.4
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Identifiers: GHSA-x5j2-g63m-f8g4
References:

• https://github.com/Argyle-Software/kyber/issues/108
• https://github.com/bwesterb/argyle-kyber/commit/b5c6ad13f4eece80e59c6ebeafd787ba1519f5f6
• https://rustsec.org/advisories/RUSTSEC-2023-0079.html
• https://github.com/advisories/GHSA-x5j2-g63m-f8g4

Repository: https://github.com/Argyle-Software/kyber
Blast Radius: 16.6

Affected Packages