CVE-2017-12293 in WebEx Meetings Server
Summary
by MITRE
A vulnerability in Cisco WebEx Meetings Server could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient limitations on the number of connections that can be made to the affected software. An attacker could exploit this vulnerability by opening multiple connections to the server and exhausting server resources. A successful exploit could cause the server to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvf41006.
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Analysis
by VulDB Data Team • 01/19/2021
The vulnerability identified as CVE-2017-12293 represents a critical denial of service weakness in Cisco WebEx Meetings Server software that exposes organizations to significant operational risks. This flaw exists within the server's connection handling mechanisms and stems from inadequate resource management controls that fail to properly limit concurrent connection attempts. The vulnerability specifically targets the server's ability to maintain proper resource allocation under stress conditions, creating an exploitable condition that can be leveraged by malicious actors without requiring authentication credentials or specialized access privileges.
The technical implementation of this vulnerability resides in the server's insufficient input validation and connection throttling mechanisms. When an attacker establishes multiple simultaneous connections to the WebEx Meetings Server, the system fails to adequately monitor or restrict the number of active sessions that can be maintained concurrently. This lack of proper connection limiting allows an attacker to systematically exhaust available system resources through resource exhaustion attacks. The flaw operates at the network protocol level where connection handling routines do not properly implement rate limiting or connection pooling controls, leading to a scenario where legitimate users may be unable to establish necessary connections while the server struggles to manage the excessive load.
The operational impact of this vulnerability extends beyond simple service disruption to encompass broader business continuity concerns for organizations relying on WebEx Meetings Server for critical communications. When successfully exploited, the vulnerability forces the server into a reload state that can last several minutes, effectively rendering the meeting platform unavailable to all users during this period. This disruption can occur at any time and without warning, potentially affecting scheduled meetings, collaborative sessions, and business-critical communications. The DoS condition can be particularly damaging in enterprise environments where WebEx serves as a primary collaboration platform for distributed teams, remote workers, and customer-facing operations.
Organizations should implement multiple layers of defense to mitigate this vulnerability, beginning with immediate patch management to address the underlying resource exhaustion issue. Network-level controls including firewall rules and connection rate limiting can help prevent exploitation attempts by restricting the number of concurrent connections from individual IP addresses. Monitoring systems should be enhanced to detect unusual connection patterns and alert administrators to potential exploitation attempts. According to CWE standards, this vulnerability maps to CWE-400 which describes "Uncontrolled Resource Consumption" and aligns with ATT&CK technique T1499.004 for "OS Command and Script Injection" as attackers may attempt to exploit resource exhaustion through various connection manipulation techniques. Additionally, implementing proper connection pooling mechanisms and establishing connection limits through configuration management will provide lasting protection against similar vulnerabilities in the future.