CVE-2011-1605 in Unified Communications Manager
Summary
by MITRE
Unspecified vulnerability in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 6.x before 6.1(5)su2, 7.x before 7.1(5b)su2, 8.0 before 8.0(3), and 8.5 before 8.5(1) allows remote attackers to cause a denial of service (process failure) via a malformed SIP message, aka Bug ID CSCth39586.
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Analysis
by VulDB Data Team • 12/01/2024
Cisco Unified Communications Manager represents a critical component in enterprise voice communication infrastructure serving as the central call control platform for IP-based phone systems. The vulnerability described in CVE-2011-1605 manifests as an unspecified weakness within the SIP message processing mechanism of CUCM versions spanning multiple release branches including 6.x, 7.x, 8.0, and 8.5. This flaw specifically affects systems running versions prior to the respective security updates su2 for 6.x and 7.x releases, and 8.0(3) and 8.5(1) for their respective major versions. The vulnerability operates through malformed SIP (Session Initiation Protocol) messages that are transmitted to the CUCM server, exploiting a processing weakness that results in system instability and complete service disruption.
The technical nature of this vulnerability involves improper handling of malformed SIP messages within the SIP processing subsystem of Cisco Unified Communications Manager. When the system receives a specially crafted SIP message that does not conform to expected protocol standards or contains invalid parameters, the processing logic fails to properly validate or sanitize the input before attempting to process the message. This leads to a process failure that can cascade into broader system instability, ultimately resulting in a denial of service condition where legitimate users cannot access voice communication services. The flaw operates at the protocol parsing level where the system lacks adequate input validation mechanisms to handle unexpected message structures. This vulnerability is categorized under CWE-129 as an insufficient input validation issue, specifically involving improper handling of malformed input data within network protocol processing components. The attack vector is remote and requires no authentication, making it particularly dangerous as any external party can exploit this weakness to disrupt critical communication services.
The operational impact of this vulnerability extends beyond simple service interruption to represent a significant threat to enterprise communication infrastructure. Organizations relying on Cisco Unified Communications Manager for their voice services face potential business disruption ranging from partial call failures to complete communication outages affecting thousands of users across enterprise networks. The vulnerability particularly affects organizations with large-scale deployments where the CUCM server serves as the central communication hub for distributed office locations, remote workers, and branch offices. Attackers can leverage this weakness to systematically disable communication services, potentially causing cascading failures that impact critical business operations, emergency response systems, and customer service capabilities. The denial of service condition can persist until system administrators manually restart affected processes or apply the necessary security patches, creating extended periods of communication disruption that can last from minutes to hours depending on the scale of the attack and response time.
Mitigation strategies for this vulnerability require immediate implementation of security updates provided by Cisco as part of their regular patch management procedures. Organizations should prioritize deployment of the specific security fixes identified in the advisory for each affected version, including the su2 updates for 6.x and 7.x releases, and the 8.0(3) and 8.5(1) releases for their respective major versions. Network segmentation and access control measures should be implemented to limit exposure of the CUCM servers to untrusted networks, while monitoring systems should be configured to detect unusual SIP traffic patterns that may indicate exploitation attempts. The implementation of SIP message filtering and validation mechanisms at network perimeters can provide additional defense-in-depth layers. Security teams should also consider implementing intrusion detection systems specifically tuned to detect malformed SIP traffic patterns associated with this vulnerability, aligning with ATT&CK technique T1071.004 for application layer protocol tunneling and T1499.004 for network disruption. Regular vulnerability assessments and penetration testing should be conducted to ensure proper patch deployment and to identify potential additional weaknesses in the communication infrastructure that could be exploited in similar fashion.