DataHub is an open-source metadata platform. When the DataHub frontend is configured to authenticate via SSO, it will leverage the pac4j library. The processing of the id_token is done in an unsafe manner which is not properly accounted for by the DataHub frontend. Specifically, if any of the id_token claims value start with the {#sb64} prefix, pac4j considers the value to be a serialized Java object and will deserialize it. This issue may lead to Remote Code Execution (RCE) in the worst case. Although a RestrictedObjectInputStream is in place, that puts some restriction on what classes can be deserialized, it still allows a broad range of java packages and potentially exploitable with different gadget chains. Users are advised to upgrade. There are no known workarounds. This vulnerability was discovered and reported by the GitHub Security lab and is tracked as GHSL-2022-086.
The product deserializes untrusted data without sufficiently verifying that the resulting data will be valid.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Datahub | Datahub_project | * | 0.9.5 (excluding) |
It is often convenient to serialize objects for communication or to save them for later use. However, deserialized data or code can often be modified without using the provided accessor functions if it does not use cryptography to protect itself. Furthermore, any cryptography would still be client-side security – which is a dangerous security assumption. Data that is untrusted can not be trusted to be well-formed. When developers place no restrictions on “gadget chains,” or series of instances and method invocations that can self-execute during the deserialization process (i.e., before the object is returned to the caller), it is sometimes possible for attackers to leverage them to perform unauthorized actions, like generating a shell.