CVE-2008-2061 in Unified Communications Manager
Summary
by MITRE
The Computer Telephony Integration (CTI) Manager service in Cisco Unified Communications Manager (CUCM) 5.x before 5.1(3c) and 6.x before 6.1(2) allows remote attackers to cause a denial of service (TSP crash) via malformed network traffic to TCP port 2748.
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Analysis
by VulDB Data Team • 08/12/2019
The vulnerability identified as CVE-2008-2061 affects the Computer Telephony Integration Manager service within Cisco Unified Communications Manager versions 5.x prior to 5.1(3c) and 6.x prior to 6.1(2). This critical flaw resides in the CTI Manager service which handles telephony integration functions within Cisco's unified communications infrastructure. The vulnerability manifests when the service receives malformed network traffic specifically directed to TCP port 2748, which is the designated port for CTI Manager communications. This port serves as the primary interface for telephony applications to interact with the Cisco Unified Communications Manager, making it a critical component in enterprise communication environments where voice and data integration occurs seamlessly.
The technical nature of this vulnerability stems from insufficient input validation within the CTI Manager service implementation. When malformed packets are transmitted to TCP port 2748, the service fails to properly sanitize or reject these invalid network communications, leading to a catastrophic failure state known as TSP (Telephony Services Process) crash. This crash represents a fundamental breakdown in the service's ability to process legitimate telephony requests, effectively rendering the CTI Manager service unavailable and disrupting all integrated telephony functions. The vulnerability operates at the network protocol level, exploiting weaknesses in the service's packet handling mechanisms and demonstrating poor error recovery procedures that are essential for maintaining system stability in mission-critical communication environments.
The operational impact of this vulnerability extends beyond simple service disruption to encompass significant business continuity risks for organizations relying on Cisco Unified Communications Manager. When the TSP crash occurs, all telephony integration services become unavailable, potentially affecting call routing, voicemail systems, automated attendants, and other integrated communication services that depend on the CTI Manager. This can result in complete communication paralysis within affected networks, particularly in enterprise environments where unified communications systems serve as the backbone for business operations. The remote nature of the attack means that malicious actors can exploit this vulnerability from external networks without requiring physical access or authentication credentials, making it particularly dangerous in environments where network segmentation is insufficient.
Organizations affected by this vulnerability should implement immediate mitigations including network segmentation to restrict access to TCP port 2748, deployment of intrusion detection systems to monitor for suspicious traffic patterns, and implementation of access control lists to limit which systems can communicate with the CTI Manager service. Cisco released patches and updates for versions 5.1(3c) and 6.1(2) that address the input validation issues and improve the service's resilience to malformed traffic. The vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and represents a classic example of how network services must properly validate all incoming data to prevent buffer overflows and service disruptions. From an ATT&CK framework perspective, this vulnerability maps to the T1489 service disruption technique, where adversaries exploit weaknesses in system services to deny access to legitimate users, making it a significant concern for enterprise security teams managing unified communications infrastructure.
This vulnerability demonstrates the critical importance of input validation and error handling in telephony and communication services, where service availability directly impacts business operations. The CTI Manager service's failure to properly handle malformed network traffic represents a fundamental security flaw that could be exploited by attackers to gain unauthorized control over critical communication infrastructure. Organizations should prioritize patch management for this vulnerability and implement comprehensive monitoring of their unified communications systems to detect and respond to similar service disruption attempts. The incident also underscores the need for robust security testing of network services, particularly those handling real-time communication data where service availability is paramount for business continuity.