When package management is enabled, Pulsar Functions, Sources and Sinks can be registered or updated from a package stored in the Pulsar Packages Management Service by supplying a package URL. The Pulsar Functions worker authorized these requests only against the namespace in which the component was being registered or updated. It did not check whether the requesting user was permitted to access packages in the namespace that the package URL refers to, and it retrieved the package from the broker using the workers own credentials. The permission check of the Packages Management Service was therefore applied to the workers identity instead of the requesting users. Package URLs of transform functions supplied when registering or updating a sink were handled in the same way.
An authenticated user who is permitted to register or update functions, sources or sinks in any namespace of their own tenant could use this to obtain the contents of a package stored in a namespace of another tenant, without having the packages permission on that namespace. The impact is limited to disclosure of package contents, which may include application code, business logic or embedded credentials. The issue does not allow packages to be modified or deleted and does not affect availability.
This issue only affects deployments that have authentication and authorization enabled and in which package management has been enabled: the broker setting enablePackagesManagement and, in current releases, the functions worker setting functionsWorkerEnablePackageManagement. Both settings are disabled by default.
This issue affects Apache Pulsar versions from 2.8.0 before 4.0.14, from 4.1.0 through 4.1.3, and from 4.2.0 before 4.2.5.
- 4.0.x version users should upgrade to at least 4.0.14.
- 4.1.x and 4.2.x version users should upgrade to at least 4.2.5.
Users operating versions prior to those listed above should upgrade to the aforementioned patched versions or newer versions.
The currently supported Apache Pulsar release lines are 4.0.x and 5.0.x. The supported versions schedule is available at https://pulsar.apache.org/contribute/release-policy/.
Weakness
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Potential Mitigations
- Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries.
- Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
- For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page.
- One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.