CVE-2023-33176: medium-severity vulnerability in bigbluebutton
Blind SSRF When Uploading Presentation in BigBlueButton
Published · Updated
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13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 4.8epss 0.5%
BigBlueButton is an open source virtual classroom designed to help teachers teach and learners learn. In affected versions are affected by a Server-Side Request Forgery (SSRF) vulnerability. In an `insertDocument` API request the user is able to supply a URL from which the presentation should be downloaded. This URL was being used without having been successfully validated first. An update to the `followRedirect` method in the `PresentationUrlDownloadService` has been made to validate all URLs to be used for presentation download. Two new properties `presentationDownloadSupportedProtocols` and `presentationDownloadBlockedHosts` have also been added to `bigbluebutton.properties` to allow administrators to define what protocols a URL must use and to explicitly define hosts that a presentation cannot be downloaded from. All URLs passed to `insertDocument` must conform to the requirements of the two previously mentioned properties. Additionally, these URLs must resolve to valid addresses, and these addresses must not be local or loopback addresses. There are no workarounds. Users are advised to upgrade to a patched version of BigBlueButton.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L
Affected products
bigbluebutton · bigbluebuttonRelated CVEs — bigbluebutton
In the same product, most dangerous first.
CVE-2022-29169HIGHReDoS on endpoint html5client/useragent in BigBlueButtonEPSS 1.6%CVE-2022-31064MEDIUMCross site scripting in username that will trigger by sending chatEPSS 1.3%CVE-2022-29232MEDIUMExposure of messages in BigBlueButton public chatsEPSS 1.1%CVE-2022-29235MEDIUMLimited data exposure for shared external videos in BigBlueButtonEPSS 1.1%CVE-2022-29233MEDIUMImproper access control for breakout rooms in BigBlue ButtonEPSS 1.1%CVE-2022-29236MEDIUMImproper access control for pencil annotations in BigBlueButtonEPSS 0.9%
References
https://github.com/bigbluebutton/bigbluebutton/commit/43394dade595d0707384e4878357901537352415https://github.com/bigbluebutton/bigbluebutton/commit/b18aff32e65a47f1eb2c800e86dcfc7a8fb05e71https://github.com/bigbluebutton/bigbluebutton/pull/18045https://github.com/bigbluebutton/bigbluebutton/pull/18052https://github.com/bigbluebutton/bigbluebutton/security/advisories/GHSA-3q22-hph2-cff7