CVE-2024-42350 Public key confusion in third party block in Biscuit
A malicious user can trick a third-party authority into generating tokens trusting the wrong keypair, bypassing authorization checks in Biscuit implementations.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-42350?
CVE-2024-42350 is a low-severity authentication bypass vulnerability in biscuit-auth biscuit, published on 5 Aug 2024. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
Biscuit is an authorization token with decentralized verification, offline attenuation and strong security policy enforcement based on a logic language. Third-party blocks can be generated without transferring the whole token to the third-party authority. Instead, a `ThirdPartyBlock` request can be sent, providing only the necessary info to generate a third-party block and to sign it: 1. the public key of the previous block (used in the signature), 2. the public keys part of the token symbol table (for public key interning in datalog expressions). A third-part block request forged by a malicious user can trick the third-party authority into generating datalog trusting the wrong keypair. Tokens with third-party blocks containing `trusted` annotations generated through a third party block request. This has been addressed in version 4 of the specification. Users are advised to update their implementations to conform. There are no known workarounds for this vulnerability.
Weakness: CWE-668
Which versions are affected by CVE-2024-42350?
How do I fix CVE-2024-42350?
Upgrade to a fixed version.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2024-42350 being exploited?
There is no known exploitation of CVE-2024-42350 in the wild and no public exploit code.