CVE-2023-33176 Blind SSRF When Uploading Presentation in BigBlueButton
Attackers can exploit a blind SSRF vulnerability in BigBlueButton's document upload feature to force the server to make arbitrary requests.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2023-33176?
CVE-2023-33176 is a medium-severity server-side request forgery vulnerability in bigbluebutton, published on 26 Jun 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-918
Which versions are affected by CVE-2023-33176?
It affects 1 product.
Products include Bigbluebutton Bigbluebutton.
How do I fix CVE-2023-33176?
No fix has been published for CVE-2023-33176 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2023-33176 being exploited?
There is no known exploitation of CVE-2023-33176 in the wild and no public exploit code.
Other vulnerabilities in bigbluebutton
Sources
Also known as GHSA-3q22-hph2-cff7.