CVE-2011-1604 in Unified Communications Manager
Summary
by MITRE
Memory leak in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 6.x before 6.1(5)su3, 7.x before 7.1(5b)su3, 8.0 before 8.0(3a)su2, and 8.5 before 8.5(1) allows remote attackers to cause a denial of service (memory consumption and process failure) via a malformed SIP message, aka Bug ID CSCti42904.
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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 system for voice and video communications. The vulnerability identified as CVE-2011-1604 affects multiple versions of this unified communications platform including releases 6.x before 6.1(5)su3, 7.x before 7.1(5b)su3, 8.0 before 8.0(3a)su2, and 8.5 before 8.5(1). This memory leak vulnerability specifically targets the Session Initiation Protocol processing capabilities within the system, creating a condition where malformed SIP messages can trigger excessive memory consumption leading to system instability and potential complete service failure.
The technical flaw manifests through improper handling of malformed SIP messages within the CUCM's signaling processing engine. When the system receives a specially crafted SIP message that deviates from expected protocol standards, the memory management routines fail to properly release allocated memory resources. This results in a gradual accumulation of memory consumption that eventually leads to process termination and system unavailability. The vulnerability operates at the application layer within the SIP protocol stack, making it particularly dangerous as it can be exploited remotely without requiring authentication credentials or physical access to the system. According to CWE-401, this represents a classic memory leak vulnerability where the system fails to properly manage dynamic memory allocation and deallocation processes.
The operational impact of this vulnerability extends far beyond simple service disruption as it directly affects business continuity and communication infrastructure reliability. Organizations relying on Cisco Unified Communications Manager for mission-critical voice services face potential downtime that can span hours or days, depending on the severity of the memory consumption and the system's response time. The remote exploitability means that attackers can initiate the denial of service condition from anywhere on the network, making it particularly dangerous in environments where external network access is permitted to SIP signaling traffic. This vulnerability aligns with ATT&CK technique T1499.004 for network denial of service and represents a significant threat to enterprise communication infrastructure security.
Mitigation strategies for this vulnerability require immediate implementation of software updates and patches provided by Cisco as part of their security advisory releases. Organizations should prioritize applying the relevant service packs and security updates that address the memory leak conditions in their specific CUCM versions. Network segmentation and access control measures should be implemented to limit exposure of SIP signaling ports to only trusted network segments. Additionally, monitoring systems should be configured to detect unusual memory consumption patterns and process failures that may indicate exploitation attempts. Implementing SIP message validation and filtering mechanisms at network boundaries can provide additional protection layers. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and proper memory management practices in enterprise communication systems.