Authentication Bypass For Endpoints With Anonymous Access in OpenCast

Vulnerability Description

In Opencast before 7.6 and 8.1, using a remember-me cookie with an arbitrary username can cause Opencast to assume proper authentication for that user even if the remember-me cookie was incorrect given that the attacked endpoint also allows anonymous access. This way, an attacker can, for example, fake a remember-me token, assume the identity of the global system administrator and request non-public content from the search service without ever providing any proper authentication. This problem is fixed in Opencast 7.6 and Opencast 8.1

References

• https://github.com/opencast/opencast/security/advisories/GHSA-vmm6-w4cf-7f3x
• https://github.com/opencast/opencast/commit/b157e1fb3b35991ca7bf59f0730329fbe7ce82e8