BigBlueButton is an open-source virtual classroom. Prior to 3.0.23, BigBlueButton exposed /bigbluebutton/api/handleJoinExistingUser through bigbluebutton-web/grails-app/controllers/org/bigbluebutton/web/controllers/ApiController.groovy. A requester able to supply an existingUserID for an active participant could reuse that participant's session and impersonate the participant in the same meeting because handleJoinExistingUser was a routable controller action rather than a private helper.
This issue is fixed in version 3.0.23.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 3
https://github.com/bigbluebutton/bigbluebutton/commit/972b04e474e195cbd708b5b3f…
security-advisories@github.com
https://github.com/bigbluebutton/bigbluebutton/releases/tag/v3.0.23
security-advisories@github.com
https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-38fw-2g…
security-advisories@github.com