CVE-2017-12224 in Meeting Server
Summary
by MITRE
A vulnerability in the ability for guest users to join meetings via a hyperlink with Cisco Meeting Server could allow an authenticated, remote attacker to enter a meeting with a hyperlink URL, even though access should be denied. The vulnerability is due to the incorrect implementation of the configuration setting Guest access via hyperlinks, which should allow the administrative user to prevent guest users from using hyperlinks to connect to meetings. An attacker could exploit this vulnerability by using a crafted hyperlink to connect to a meeting. An exploit could allow the attacker to connect directly to the meeting with a hyperlink, even though access should be denied. The attacker would still require a valid hyperlink and encoded secret identifier to be connected. Cisco Bug IDs: CSCve20873.
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Analysis
by VulDB Data Team • 01/11/2021
This vulnerability resides in Cisco Meeting Server's guest access control mechanism, specifically affecting the configuration setting that governs hyperlink-based meeting participation. The flaw represents a critical authorization bypass that undermines the intended security boundaries between authenticated and unauthorized users within the collaboration platform. The vulnerability stems from improper validation of guest access permissions when users attempt to join meetings through hyperlinks, creating an unexpected pathway for unauthorized access despite administrative controls. This issue directly impacts the integrity of access control policies that should prevent guest users from utilizing hyperlink mechanisms to enter meetings, effectively allowing attackers to circumvent established security configurations.
The technical implementation flaw manifests in how the system processes hyperlink-based meeting joins, where the authentication and authorization checks fail to properly validate whether guest access should be permitted through the hyperlink mechanism. Attackers can exploit this by crafting malicious hyperlinks that bypass the intended access restrictions, enabling them to join meetings without proper authorization. The vulnerability requires an attacker to possess a valid hyperlink with an encoded secret identifier, but once obtained, it allows direct meeting participation that should otherwise be restricted. This represents a failure in the principle of least privilege and demonstrates inadequate input validation in the meeting access control flow. The vulnerability aligns with CWE-285, which addresses improper authorization in access control systems, and specifically relates to the improper enforcement of access control policies.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it creates potential for information disclosure, meeting disruption, and unauthorized participation in sensitive collaborative sessions. An attacker could exploit this vulnerability to gain access to confidential meeting content, participate in privileged discussions, or potentially disrupt ongoing meetings. The vulnerability affects organizations that rely on Cisco Meeting Server for secure collaboration, particularly those with strict guest access policies and sensitive meeting content. The exploitability requires an attacker to have knowledge of valid meeting hyperlinks and their encoded identifiers, but once obtained, the attack can be executed without requiring additional authentication credentials beyond what is already provided in the hyperlink itself. This vulnerability significantly undermines the security posture of organizations using Cisco Meeting Server and represents a critical gap in the platform's access control implementation.
Organizations should implement immediate mitigations including verification of guest access configuration settings, review of existing hyperlink distribution practices, and monitoring for unauthorized meeting access attempts. Cisco has released patches and updates to address this vulnerability through the CSCve20873 bug fix, which should be applied immediately to all affected systems. Security teams should also implement network monitoring to detect unusual hyperlink-based meeting access patterns and establish more robust access control policies for meeting participation. The vulnerability highlights the importance of proper access control implementation and the need for comprehensive testing of security configurations in collaboration platforms. Organizations should conduct thorough assessments of their meeting server configurations to ensure that guest access policies are properly enforced and that no unauthorized access pathways exist through hyperlink mechanisms. This vulnerability serves as a reminder of the critical importance of validating access control implementations in enterprise collaboration systems and the potential consequences of configuration errors in security-critical applications.