CVE-2020-3142 in Webex Meetings Suite
Summary
by MITRE
[CVE-2020-3142_su] A vulnerability in Cisco Webex Meetings Suite sites and Cisco Webex Meetings Online sites could allow an unauthenticated, remote attendee to join a password-protected meeting without providing the meeting password. The connection attempt must initiate from a Webex mobile application for either iOS or Android. The vulnerability is due to unintended meeting information exposure in a specific meeting join flow for mobile applications. An unauthorized attendee could exploit this vulnerability by accessing a known meeting ID or meeting URL from the mobile device’s web browser. The browser will then request to launch the device’s Webex mobile application. A successful exploit could allow the unauthorized attendee to join the password-protected meeting. The unauthorized attendee will be visible in the attendee list of the meeting as a mobile attendee. Cisco has applied updates that address this vulnerability and no user action is required.
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Analysis
by VulDB Data Team • 03/26/2024
This vulnerability exists within Cisco Webex Meetings Suite and Cisco Webex Meetings Online platforms, representing a critical authentication bypass flaw that undermines the security of password-protected meetings. The vulnerability stems from improper handling of meeting join flows specifically within mobile applications, creating an unintended information exposure channel that allows unauthorized access to protected sessions. The flaw affects both iOS and Android mobile applications and operates through a sophisticated attack vector that leverages the mobile application's deep linking capabilities. According to the Common Weakness Enumeration framework, this vulnerability maps to CWE-287 which describes improper authentication scenarios, while the ATT&CK framework categorizes this under T1110.003 for credential access through unsecured network protocols and T1071.004 for application layer protocol usage in web services.
The technical exploitation mechanism relies on the mobile application's automatic launching behavior when encountering specific meeting URLs or identifiers. When a user attempts to join a meeting through a mobile browser, the system triggers an automatic launch of the Webex mobile application, bypassing the normal authentication sequence that should require a valid meeting password. This occurs because the meeting information, including meeting identifiers and potentially other session details, is inadvertently exposed during the URL processing flow. The vulnerability specifically requires the initial connection attempt to originate from a mobile device's web browser, making it a client-side exploitation vector that leverages the trust relationship between the browser and mobile application. Attackers can exploit this by simply knowing a valid meeting ID or URL, without requiring any additional credentials or prior access to the meeting.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it creates persistent visibility issues within meetings. Unauthorized attendees who successfully exploit this vulnerability become visible in the meeting attendee list as mobile participants, potentially compromising meeting confidentiality and allowing for further social engineering attacks. The vulnerability affects both scheduled and ad-hoc meetings, with the most significant risk occurring in environments where sensitive discussions take place, such as corporate boardrooms, legal proceedings, or medical consultations. The fact that no user action is required for the fix indicates that Cisco has implemented a comprehensive patch that addresses the root cause at the application layer, likely through improved URL parameter validation and authentication flow management.
Organizations should prioritize applying the available patches immediately, as the vulnerability creates a persistent risk for all users of Cisco Webex Meetings Suite. The remediation approach taken by Cisco demonstrates proper vulnerability management practices, addressing the issue at the source rather than implementing workarounds. Security teams should also conduct network monitoring to detect any potential exploitation attempts and establish incident response procedures for handling unauthorized meeting access. The vulnerability highlights the importance of mobile application security testing, particularly around deep linking and URL handling mechanisms. Organizations should consider implementing additional network controls or authentication layers as defense-in-depth measures, while also educating users about the risks of sharing meeting URLs and the importance of verifying meeting security settings. The patch deployment represents a critical security update that resolves the unintended information exposure through the mobile application join flow, restoring proper authentication controls for all password-protected meetings.