CVE-2011-4486 in Unified Communications Manager
Summary
by MITRE
Cisco Unified Communications Manager (CUCM) with software 6.x and 7.x before 7.1(5b)su5, 8.0 before 8.0(3a)su3, and 8.5 and 8.6 before 8.6(2a)su1 and Cisco Business Edition 3000 with software before 8.6.3 and 5000 and 6000 with software before 8.6(2a)su1 allow remote attackers to cause a denial of service (device reload) via a crafted SCCP registration, aka Bug ID CSCtu73538.
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Analysis
by VulDB Data Team • 04/09/2017
The vulnerability identified as CVE-2011-4486 affects Cisco Unified Communications Manager versions 6.x and 7.x prior to 7.1(5b)su5, 8.0 prior to 8.0(3a)su3, and 8.5 and 8.6 prior to 8.6(2a)su1, along with Cisco Business Edition 3000 before 8.6.3 and Cisco 5000 and 6000 series before 8.6(2a)su1. This vulnerability represents a critical remote denial of service flaw that allows attackers to remotely trigger device reloads through manipulation of SCCP (Skinny Client Control Protocol) registration messages. The issue stems from insufficient input validation within the SCCP processing mechanism, specifically when handling malformed registration requests from remote endpoints. The vulnerability is classified under CWE-20 as a weakness involving improper input validation, making it susceptible to exploitation through crafted payloads that exploit buffer handling deficiencies in the communication stack. The root cause lies in the failure to properly sanitize and validate SCCP registration parameters, allowing malicious actors to inject malformed data that causes the system to crash and restart.
The operational impact of this vulnerability is severe as it enables remote attackers to perform denial of service attacks against critical communication infrastructure without requiring authentication or privileged access. When exploited, the vulnerability causes the affected Cisco Unified Communications Manager devices to reload their operating systems, resulting in temporary disruption of voice services and potentially extended downtime depending on the recovery process. The attack vector involves sending specially crafted SCCP registration messages to the target system, which when processed trigger an exception in the system's handling of registration requests. This behavior aligns with ATT&CK technique T1499.004 for network denial of service attacks, where adversaries leverage protocol weaknesses to disrupt services. The vulnerability affects both on-premise and cloud-based unified communications deployments, potentially impacting enterprise voice infrastructure and business continuity. The impact is particularly concerning as it affects multiple major versions of Cisco's unified communications platform, suggesting a widespread exposure across enterprise networks that rely on these systems for critical communication services.
Mitigation strategies for CVE-2011-4486 should prioritize immediate implementation of official Cisco security patches and software updates. Organizations must upgrade to the patched versions mentioned in the CVE description, specifically 7.1(5b)su5 for 6.x and 7.x systems, 8.0(3a)su3 for 8.0 systems, and 8.6(2a)su1 for 8.5 and 8.6 systems. Network segmentation and access control measures should be implemented to limit direct exposure of CUCM systems to untrusted networks, particularly by restricting SCCP traffic to trusted endpoints only. The implementation of network monitoring solutions can help detect anomalous SCCP registration patterns that may indicate exploitation attempts. Cisco recommends configuring access control lists to filter SCCP traffic and implementing rate limiting mechanisms to prevent abuse of the registration process. Additionally, organizations should consider deploying intrusion detection systems that can identify and alert on suspicious SCCP packet structures. The vulnerability demonstrates the importance of maintaining up-to-date security patches and highlights the risks associated with legacy systems that may not receive continued support. Organizations should also implement comprehensive network access control policies and regularly audit their unified communications infrastructure to ensure that only authorized devices can register with the CUCM systems. The remediation process should include thorough testing of patches in non-production environments to avoid potential compatibility issues with existing voice infrastructure components.