data/reports/GO-2023-1765.yaml

id: GO-2023-1765
modules:
    - module: github.com/cloudflare/circl
      versions:
        - fixed: 1.3.3
      vulnerable_at: 1.3.2
      packages:
        - package: github.com/cloudflare/circl/abe/cpabe/tkn20/internal/tkn
          symbols:
            - EncryptCCA
        - package: github.com/cloudflare/circl/blindsign/blindrsa
          symbols:
            - RSAVerifier.Blind
        - package: github.com/cloudflare/circl/kem/frodo/frodo640shake
          symbols:
            - PublicKey.EncapsulateTo
          derived_symbols:
            - scheme.Encapsulate
            - scheme.EncapsulateDeterministically
        - package: github.com/cloudflare/circl/kem/kyber/kyber1024
          symbols:
            - PublicKey.EncapsulateTo
          derived_symbols:
            - scheme.Encapsulate
            - scheme.EncapsulateDeterministically
        - package: github.com/cloudflare/circl/kem/kyber/kyber512
          symbols:
            - PublicKey.EncapsulateTo
          derived_symbols:
            - scheme.Encapsulate
            - scheme.EncapsulateDeterministically
        - package: github.com/cloudflare/circl/kem/kyber/kyber768
          symbols:
            - PublicKey.EncapsulateTo
          derived_symbols:
            - scheme.Encapsulate
            - scheme.EncapsulateDeterministically
        - package: github.com/cloudflare/circl/kem/sike/sikep434
          symbols:
            - scheme.Encapsulate
        - package: github.com/cloudflare/circl/kem/sike/sikep503
          symbols:
            - scheme.Encapsulate
        - package: github.com/cloudflare/circl/kem/sike/sikep751
          symbols:
            - scheme.Encapsulate
summary: Leaked shared secret and weak blinding in github.com/cloudflare/circl
description: |-
    When sampling randomness for a shared secret, the implementation of Kyber and
    FrodoKEM, did not check whether crypto/rand.Read() returns an error. In rare
    deployment cases (error thrown by the Read() function), this could lead to a
    predictable shared secret.

    The tkn20 and blindrsa components did not check whether enough randomness was
    returned from the user provided randomness source. Typically the user provides
    crypto/rand.Reader, which in the vast majority of cases will always return the
    right number random bytes. In the cases where it does not, or the user provides
    a source that does not, the blinding for blindrsa is weak and integrity of the
    plaintext is not ensured in tkn20.
cves:
    - CVE-2023-1732
ghsas:
    - GHSA-2q89-485c-9j2x
references:
    - advisory: https://github.com/cloudflare/circl/security/advisories/GHSA-2q89-485c-9j2x
    - fix: https://github.com/cloudflare/circl/commit/ff8d91225f8954b4970b6d6382d2e4c78f4a4cf8
review_status: REVIEWED