CVE-2024-21670 CL-Signatures Revocation Scheme in Ursa has flaws that allow a holder to demonstrate non-revocation of a revoked credential

2024-01-1621:44:05

CWE-327

GitHub_M

github.com

ursa

cl-signatures

revocation scheme

privacy guarantees

non-revocation proof

anoncreds

verifiable credential model

flaw

end-of-life

6.5 Medium

CVSS3

Attack Vector

PHYSICAL

Attack Complexity

HIGH

Privileges Required

HIGH

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:P/AC:H/PR:H/UI:R/S:C/C:H/I:H/A:N

6.7 Medium

AI Score

Confidence

Low

0.001 Low

EPSS

Percentile

39.3%

JSON

Ursa is a cryptographic library for use with blockchains. The revocation schema that is part of the Ursa CL-Signatures implementations has a flaw that could impact the privacy guarantees defined by the AnonCreds verifiable credential model, allowing a malicious holder of a revoked credential to generate a valid Non-Revocation Proof for that credential as part of an AnonCreds presentation. A verifier may verify a credential from a holder as being “not revoked” when in fact, the holder’s credential has been revoked. Ursa has moved to end-of-life status and no fix is expected.

CNA Affected

[
  {
    "vendor": "hyperledger-archives",
    "product": "ursa",
    "versions": [
      {
        "version": "<= 0.3.7",
        "status": "affected"
      }
    ]
  }
]