Information disclosure in BigBlueButton - CVE-2020-12443
Published: April 29, 2020
Vulnerability identifier: #VU27433
CSH Severity: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/U:Green
CVE-ID: CVE-2020-12443
CWE-ID: CWE-200
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
BigBlueButton
BigBlueButton
Software vendor:
Blindside Networks
Blindside Networks
Description
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to an ineffective mitigation to CVE-2020-12112 (SB2020042820) in which there was an attempted fix within an NGINX configuration file, without considering that the relevant part of NGINX is case-insensitive. A remote attacker can read arbitrary files because the presfilename (lowercase) value can be a .pdf filename while the presFilename (mixed case) value has a ../ sequence.
Remediation
Install updates from vendor's website.