CVE-2011-1606 in Unified Communications Manager
Summary
by MITRE
Unspecified vulnerability in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 6.x before 6.1(5)su2, 7.x before 7.1(5)su1, 8.0 before 8.0(3), and 8.5 before 8.5(1) allows remote attackers to cause a denial of service (process failure) via a malformed SIP message, aka Bug ID CSCtg62855.
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Analysis
by VulDB Data Team • 12/01/2024
Cisco Unified Communications Manager represents a critical component in enterprise communication infrastructure serving as the central call control system for voice and video communications. This vulnerability affects multiple versions of the platform including 6.x series before 6.1(5)su2, 7.x series before 7.1(5)su1, 8.0 series before 8.0(3), and 8.5 series before 8.5(1) releases. The flaw manifests as an unspecified vulnerability that specifically targets the SIP (Session Initiation Protocol) message processing functionality within the system. This vulnerability falls under the category of denial of service attacks where malicious actors can exploit the system's handling of malformed SIP messages to trigger process failures that ultimately result in service disruption.
The technical implementation of this vulnerability involves the improper validation and handling of SIP protocol messages received by the Cisco Unified Communications Manager system. When the system encounters a malformed SIP message, its processing logic fails to properly sanitize or reject the invalid input, leading to an abrupt termination of critical processes. This behavior represents a classic buffer overflow or input validation flaw that allows attackers to craft specific SIP messages designed to trigger the system's failure mechanisms. The vulnerability is particularly concerning because SIP is a fundamental protocol for establishing, modifying, and terminating real-time sessions that include voice, video, and messaging applications within the communication infrastructure.
From an operational impact perspective, this vulnerability creates significant risk for enterprise environments that rely on Cisco Unified Communications Manager for their core communication services. A successful exploitation can result in complete disruption of voice and video communication services, affecting thousands of users within an organization simultaneously. The denial of service condition can persist until manual intervention occurs through system restarts or software patches, creating extended downtime periods that can severely impact business operations. The attack vector is particularly dangerous as it requires no authentication or specialized privileges, making it accessible to any remote attacker who can send SIP messages to the targeted system. This vulnerability directly impacts the availability aspect of the CIA triad and can be classified under CWE-121 for buffer overflow conditions or CWE-20 for input validation issues.
The attack surface for this vulnerability extends across enterprise networks where Cisco Unified Communications Manager serves as the primary communication platform for voice services. Organizations using this system typically have it exposed to external networks through firewalls and NAT configurations to allow legitimate SIP signaling from remote users and partners. The vulnerability enables attackers to perform denial of service attacks without requiring any credentials or privileged access, making it an attractive target for malicious actors seeking to disrupt business communications. This particular vulnerability aligns with ATT&CK technique T1499.004 for network denial of service attacks and demonstrates how weaknesses in protocol handling can be exploited to create widespread service disruption. The impact extends beyond immediate communication failures to include potential business continuity issues, customer service degradation, and financial losses due to extended downtime periods.
Organizations should implement immediate mitigation strategies including applying the vendor-provided security patches and updates that address the specific vulnerability in their Cisco Unified Communications Manager versions. Network segmentation and firewall rules should be configured to limit exposure of the SIP signaling ports to only trusted networks and IP addresses. Monitoring and logging of SIP traffic should be enhanced to detect anomalous message patterns that may indicate exploitation attempts. Regular vulnerability assessments and security audits should be conducted to identify similar weaknesses in other communication infrastructure components. The implementation of intrusion detection systems specifically configured to monitor SIP protocol anomalies can provide early warning of potential exploitation attempts. Additionally, organizations should establish incident response procedures that include rapid deployment of patches and recovery protocols to minimize the impact of any successful exploitation attempts.