CVE-2009-2864 in Unified Callmanager
Summary
by MITRE
Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 5.x before 5.1(3g), 6.x before 6.1(4), 7.0.x before 7.0(2a)su1, and 7.1.x before 7.1(2) allows remote attackers to cause a denial of service (service restart) via malformed SIP messages, aka Bug ID CSCsz95423.
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Analysis
by VulDB Data Team • 11/29/2024
Cisco Unified Communications Manager represents a critical component in enterprise voice communication infrastructures, serving as the central call control platform for voice and video communications. This vulnerability affects multiple versions of the CUCM software including 5.x through 7.1.x releases, making it particularly concerning given the widespread deployment of these systems across enterprise networks. The vulnerability manifests through improper handling of Session Initiation Protocol messages, which form the backbone of modern VoIP communications and enable the setup, modification, and termination of multimedia sessions. Attackers can exploit this weakness by crafting specially malformed SIP messages that trigger unexpected behavior in the CUCM service.
The technical flaw resides in the insufficient input validation mechanisms within the SIP message processing component of CUCM. When the system receives malformed SIP messages containing invalid or unexpected data structures, the parsing routines fail to properly handle these edge cases, leading to service instability. This particular vulnerability falls under the category of improper input validation as defined by CWE-20, where the application does not adequately validate or sanitize input data before processing. The malformed SIP messages exploit buffer overflows or parsing errors that cause the CUCM service to crash and restart automatically, effectively creating a denial of service condition that disrupts critical communication services.
The operational impact of this vulnerability extends far beyond simple service disruption, as it can severely compromise business continuity and communication availability within enterprise environments. Organizations relying on CUCM for their voice infrastructure face potential downtime that could affect thousands of users simultaneously, particularly in large enterprises where communication systems are mission-critical. The automatic service restart creates a cascading effect that may impact other integrated systems, as communication outages can affect emergency services, customer support operations, and internal business processes. According to ATT&CK framework, this vulnerability maps to T1499.004 (Network Denial of Service) and T1071.004 (Application Layer Protocol: SIP) as it exploits weaknesses in application layer protocols to cause service disruption.
Mitigation strategies should focus on immediate patch deployment as provided by Cisco security advisories, which address the input validation flaws in the SIP message handling components. Organizations should implement network segmentation and access controls to limit exposure to potentially malicious SIP traffic, particularly at network perimeters where external communications enter the enterprise infrastructure. Network monitoring solutions should be configured to detect unusual SIP traffic patterns and potential exploitation attempts, enabling rapid incident response capabilities. Additionally, implementing rate limiting and message filtering mechanisms can help reduce the impact of malformed SIP messages reaching the core CUCM infrastructure. The vulnerability demonstrates the importance of robust input validation and proper error handling in communication protocols, aligning with security best practices outlined in NIST SP 800-160 and ISO 27001 standards for secure system design and implementation.