CVE-2022-31021 Unlinkability broken in ursa when verifiers use malicious keys
A malicious issuer can break unlinkability in AnonCreds credentials by using weakened private keys, allowing them to track holders.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2022-31021?
CVE-2022-31021 is a low-severity vulnerability in hyperledger ursa, published on 16 Jan 2024. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
Ursa is a cryptographic library for use with blockchains. A weakness in the Hyperledger AnonCreds specification that is not mitigated in the Ursa and AnonCreds implementations is that the Issuer does not publish a key correctness proof demonstrating that a generated private key is sufficient to meet the unlinkability guarantees of AnonCreds. The Ursa and AnonCreds CL-Signatures implementations always generate a sufficient private key. A malicious issuer could in theory create a custom CL Signature implementation (derived from the Ursa or AnonCreds CL-Signatures implementations) that uses weakened private keys such that presentations from holders could be shared by verifiers to the issuer who could determine the holder to which the credential was issued. This vulnerability could impact holders of AnonCreds credentials implemented using the CL-signature scheme in the Ursa and AnonCreds implementations of CL Signatures. The ursa project has has moved to end-of-life status and no fix is expected.
Weakness: CWE-829
Which versions are affected by CVE-2022-31021?
4 open source packages ship an affected version, including ursa and anoncreds-clsignatures. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
ursa crates.io | All versions to 0.3.7 | None |
ursa crates.io | All versions to 0.3.7 | None |
anoncreds-clsignatures crates.io | All versions | None |
anoncreds-clsignatures crates.io | All versions | None |
Products include Hyperledger Ursa.
How do I fix CVE-2022-31021?
No fix has been published for CVE-2022-31021 yet. Limit exposure of the affected software until one is available.
Is CVE-2022-31021 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2022-31021 exists.
Other vulnerabilities in hyperledger ursa
Sources
Also known as GHSA-2q6j-gqc4-4gw3.