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Ursa CL-Signatures Revocation allows verifiers to generate unique identifiers for holders

Moderate severity GitHub Reviewed Published Jan 16, 2024 in hyperledger-archives/ursa • Updated Jan 28, 2024

Package

cargo anoncreds-clsignatures (Rust)

Affected versions

< 0.1.0

Patched versions

0.1.0
cargo ursa (Rust)
<= 0.3.7
None

Description

Summary

The revocation scheme 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. Notably, a malicious verifier may be able to generate a unique identifier for a holder providing a verifiable presentation that includes a Non-Revocation proof.

Details

The revocation scheme 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, potentially allowing a malicious verifier to generate a unique identifier for a holder that provides a verifiable presentation that includes a Non-Revocation proof.

The flaws affects all CL-Signature versions published from the Hyperledger Ursa repository to the Ursa Rust Crate, and is fixed in all versions published from the Hyperledger AnonCreds CL-Signatures repository to the AnonCreds CL-Signatures Rust Crate.

The addressing the flaw requires updating AnonCreds holder software (such as mobile wallets) to a corrected CL-Signature implementation, such as the [AnonCreds CL Signatures Rust Crate]. Verifying presentations from corrected holders requires a updating the verifier software to a corrected CL-Signatures implementation. An updated verifier based on AnonCreds CL-Signatures can verify presentations from holders built on either the flawed Ursa CL-Signature implementation or a corrected CL-Signature implementation

The flaw occurs as a result of generating a verifiable presentation that includes a Non-Revocation proof from a flawed implementation.

Impact

The impact of the flaw is that a malicious verifier may be able to determine a unique identifier for a holder presenting a Non-Revocation proof.

Mitigation

Upgrade libraries/holder applications that generate AnonCreds verifiable presentations using the Ursa Rust Crate to any version of the AnonCreds CL-Signatures Rust Crate.

References

@swcurran swcurran published to hyperledger-archives/ursa Jan 16, 2024
Published to the GitHub Advisory Database Jan 16, 2024
Reviewed Jan 16, 2024
Published by the National Vulnerability Database Jan 16, 2024
Last updated Jan 28, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS score

0.087%
(38th percentile)

Weaknesses

CVE ID

CVE-2024-22192

GHSA ID

GHSA-6698-mhxx-r84g
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