Vulnerability Details : CVE-2020-12443
BigBlueButton before 2.2.6 allows remote attackers to read arbitrary files because the presfilename (lowercase) value can be a .pdf filename while the presFilename (mixed case) value has a ../ sequence. This can be leveraged for privilege escalation via a directory traversal to bigbluebutton.properties. NOTE: this issue exists because of an ineffective mitigation to CVE-2020-12112 in which there was an attempted fix within an NGINX configuration file, without considering that the relevant part of NGINX is case-insensitive.
Vulnerability category: Directory traversalGain privilege
Products affected by CVE-2020-12443
- cpe:2.3:a:bigbluebutton:bigbluebutton:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2020-12443
0.68%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 78 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2020-12443
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
7.5
|
HIGH | AV:N/AC:L/Au:N/C:P/I:P/A:P |
10.0
|
6.4
|
NIST | |
9.8
|
CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
3.9
|
5.9
|
NIST |
CWE ids for CVE-2020-12443
-
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.Assigned by: nvd@nist.gov (Primary)
References for CVE-2020-12443
-
https://github.com/mclab-hbrs/BBB-POC
GitHub - mclab-hbrs/BBB-POC: Proof Of Concept Exploit For BBB v2.2.5Exploit;Third Party Advisory
-
https://github.com/bigbluebutton/bigbluebutton/pull/9259/commits/b21ca8355a57286a1e6df96984b3a4c57679a463
Return 404 error when presentation file download is not allowed. by GhaziTriki · Pull Request #9259 · bigbluebutton/bigbluebutton · GitHubPatch;Third Party Advisory
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