CVE-2013-1133 in Unified Communications Manager
Summary
by MITRE
Cisco Unified Communications Manager (CUCM) 8.6 before 8.6(2a)su2, 8.6 BE3k before 8.6(4) BE3k, and 9.x before 9.0(1) allows remote attackers to cause a denial of service (CPU consumption and GUI and voice outages) via malformed packets to unused UDP ports, aka Bug ID CSCtx43337.
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Analysis
by VulDB Data Team • 12/29/2021
Cisco Unified Communications Manager versions 8.6 before 8.6(2a)su2, 8.6 BE3k before 8.6(4) BE3k, and 9.x before 9.0(1) contain a vulnerability that enables remote attackers to trigger denial of service conditions through the exploitation of improperly handled UDP packet processing. This vulnerability specifically affects unused UDP ports within the system architecture, allowing malicious actors to consume excessive CPU resources and subsequently cause complete service outages affecting both graphical user interface operations and voice communication capabilities. The flaw stems from inadequate validation mechanisms within the packet processing routines that fail to properly handle malformed UDP packets destined for ports that are not actively listening or configured for communication. This vulnerability directly maps to CWE-129 Input Validation and CWE-400 Uncontrolled Resource Consumption, representing a classic example of resource exhaustion attacks that can severely impact mission-critical communication infrastructures.
The operational impact of this vulnerability extends beyond simple service disruption to encompass complete communication system failures that can affect enterprise-wide voice and data services. When attackers send malformed UDP packets to unused ports, the system processes these packets through its normal packet handling routines without proper filtering or validation, causing CPU utilization to spike dramatically. This resource exhaustion results in cascading failures where legitimate voice calls may drop, GUI interfaces become unresponsive, and overall system stability deteriorates significantly. The vulnerability affects the core communication infrastructure of enterprises relying on Cisco Unified Communications Manager, potentially disrupting business operations and communication workflows across departments that depend on voice services and unified communication platforms. The attack vector requires no authentication or specialized privileges, making it particularly dangerous as any remote attacker can exploit this weakness to cause system-wide outages.
Organizations affected by this vulnerability should implement immediate mitigation strategies to protect their communication infrastructure from exploitation. The most effective approach involves applying the relevant Cisco security patches and software updates that address the specific packet handling flaws in the affected versions. Network segmentation and access control measures should be implemented to limit exposure of the vulnerable system to untrusted networks, particularly by blocking unnecessary UDP port access from external sources. Implementing rate limiting and packet filtering rules at network boundaries can help reduce the impact of malformed packet attacks by preventing excessive traffic from reaching the vulnerable system components. The mitigation strategies align with ATT&CK techniques focused on credential access and defense evasion, as they involve both perimeter security hardening and internal system patching to prevent exploitation. System administrators should also monitor for unusual CPU utilization patterns and implement automated alerting mechanisms to detect potential exploitation attempts. Regular vulnerability assessments and security audits should be conducted to ensure that all communication infrastructure components remain protected against similar vulnerabilities and that patch management processes are effectively implemented across the enterprise network.