CVE-2011-2072 in Unified Communications Manager
Summary
by MITRE
Memory leak in Cisco IOS 12.4, 15.0, and 15.1, Cisco IOS XE 2.5.x through 3.2.x, and Cisco Unified Communications Manager (CUCM) 6.x and 7.x before 7.1(5b)su4, 8.x before 8.5(1)su2, and 8.6 before 8.6(1) allows remote attackers to cause a denial of service (memory consumption and device reload or process failure) via a malformed SIP message, aka Bug IDs CSCtl86047 and CSCto88686.
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Analysis
by VulDB Data Team • 11/21/2021
The vulnerability described in CVE-2011-2072 represents a critical memory leak issue affecting multiple Cisco networking and communications platforms including IOS versions 12.4, 15.0, and 15.1, IOS XE versions 2.5.x through 3.2.x, and Cisco Unified Communications Manager versions 6.x, 7.x, and 8.x. This flaw specifically targets the Session Initiation Protocol (SIP) processing functionality within these systems, creating a pathway for remote attackers to exploit the memory management mechanisms through crafted malformed SIP messages. The vulnerability is categorized under CWE-401 as a weakness related to improper handling of memory allocation and deallocation, making it a classic example of memory leak exploitation that can lead to system instability and service disruption. The attack vector is particularly concerning as it operates over the network without requiring authentication, allowing remote adversaries to leverage this weakness from outside the network perimeter.
The technical implementation of this vulnerability stems from insufficient validation and proper memory management within the SIP message processing components of affected Cisco products. When a malformed SIP message is received, the system fails to properly release allocated memory resources, causing progressive memory consumption over time. This memory leak eventually leads to system resource exhaustion, manifesting as device reloads, process failures, or complete service unavailability. The specific bug identifiers CSCtl86047 and CSCto88686 highlight the targeted nature of this flaw within Cisco's internal tracking systems, indicating that this was recognized as a significant issue requiring immediate attention. The vulnerability demonstrates characteristics consistent with the ATT&CK framework's T1499.004 technique for network denial of service, where adversaries leverage application-level flaws to consume system resources and render services unavailable.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the reliability and availability of critical communication infrastructure. For organizations relying on Cisco Unified Communications Manager for voice and video services, this vulnerability could result in complete communication outages affecting business operations and emergency services. The memory consumption pattern creates a gradual degradation that may go unnoticed until the system reaches critical resource exhaustion levels, making detection challenging for network administrators. The vulnerability affects both enterprise and service provider environments, with the potential for cascading failures in interconnected systems where communication services depend on stable infrastructure. Organizations may experience unexpected device reboots, call failures, and service interruptions that can significantly impact productivity and customer service availability.
Mitigation strategies for CVE-2011-2072 should prioritize immediate patch deployment for all affected Cisco products, with particular attention to the specific version ranges mentioned in the vulnerability description. Network administrators should implement SIP message filtering and validation at perimeter devices to prevent malformed messages from reaching vulnerable systems, utilizing access control lists and intrusion prevention systems to block suspicious traffic patterns. The implementation of monitoring solutions that track memory usage and process behavior can help detect early signs of memory leak exploitation before complete service failure occurs. Organizations should also consider implementing redundant systems and failover mechanisms to maintain communication services during potential exploitation events. Additionally, regular security assessments and vulnerability scanning should be conducted to identify any other potentially affected systems within the network infrastructure, ensuring comprehensive protection against similar memory management vulnerabilities that may exist in other network components or applications.