CVE-2020-5231 Opencast users with ROLE_COURSE_ADMIN can create new users

What is CVE-2020-5231?

CVE-2020-5231 is a medium-severity missing authorization vulnerability in opencast, published on 30 Jan 2020. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

Official description

In Opencast before 7.6 and 8.1, users with the role ROLE_COURSE_ADMIN can use the user-utils endpoint to create new users not including the role ROLE_ADMIN. ROLE_COURSE_ADMIN is a non-standard role in Opencast which is referenced neither in the documentation nor in any code (except for tests) but only in the security configuration. From the name – implying an admin for a specific course – users would never expect that this role allows user creation. This issue is fixed in 7.6 and 8.1 which both ship a new default security configuration.

Weakness: CWE-276, CWE-285

Which versions are affected by CVE-2020-5231?

4 open source packages ship an affected version, including org.opencastproject:opencast-kernel. It affects 1 product.

Products include Apereo Opencast.

How do I fix CVE-2020-5231?

Upgrade org.opencastproject:opencast-kernel to a fixed version for your release line: 7.6 or 8.1.

Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.

Is CVE-2020-5231 being exploited?

There is no known exploitation of CVE-2020-5231 in the wild and no public exploit code.

Other vulnerabilities in opencast

• CVE-2021-43821 Files Accessible to External Parties in Opencast Critical 9.9
• CVE-2020-5206 Authentication Bypass For Endpoints With Anonymous Access in OpenCast High 8.7
• CVE-2021-32623 Opencast vulnerable to billion laughs attack (XML bomb) High 8.1
• CVE-2020-5229 Opencast stores passwords using outdated MD5 hash algorithm High 7.7
• CVE-2020-5230 Opencast uses unsafe identifiers High 7.7

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-94qw-r73x-j7hg.