CVE-2008-1745 in Unified Communications Manager
Summary
by MITRE
Cisco Unified Communications Manager (CUCM) 5.x before 5.1(2) and 6.x before 6.1(1) allows remote attackers to cause a denial of service (service interruption) via a SIP JOIN message with a malformed header, aka Bug ID CSCsi48115.
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Analysis
by VulDB Data Team • 08/10/2019
Cisco Unified Communications Manager versions 5.x prior to 5.1(2) and 6.x prior to 6.1(1) contain a vulnerability in their Session Initiation Protocol implementation that enables remote attackers to trigger service interruption through malformed SIP JOIN messages. This vulnerability specifically targets the handling of SIP headers within the JOIN message type, where the system fails to properly validate or sanitize incoming header data before processing. The flaw occurs during the SIP signaling process when the CUCM server receives a JOIN message containing malformed header values that exceed expected parameter boundaries or contain unexpected character sequences. This weakness falls under CWE-129, Input Validation, and represents a classic buffer overflow scenario where insufficient bounds checking allows malicious input to disrupt normal service operations. The vulnerability is particularly dangerous because it can be exploited remotely without authentication, making it accessible to any attacker capable of sending SIP messages to the target system. When the malformed header data is processed, the CUCM service becomes unstable and typically results in immediate service interruption or complete system crash, effectively rendering the communication platform unavailable to legitimate users. The impact extends beyond simple service disruption as it can affect critical business communications, particularly in enterprise environments where CUCM serves as the primary voice communication infrastructure. This vulnerability aligns with ATT&CK technique T1499.004, Network Denial of Service, and represents a significant risk to business continuity. Organizations utilizing affected CUCM versions face potential operational downtime, communication failures, and increased risk of service disruption during critical business hours. The vulnerability demonstrates a lack of proper input sanitization and error handling within the SIP processing pipeline, where the system does not adequately protect against malformed data that could cause memory corruption or process termination.
The exploitation of this vulnerability requires minimal technical expertise and can be accomplished through automated tools that craft malicious SIP JOIN messages with carefully constructed malformed headers. Attackers can leverage this weakness to repeatedly disrupt service availability, potentially causing cascading effects throughout the enterprise communication network. The affected versions of CUCM do not implement robust header validation mechanisms, allowing malformed data to propagate through the system without proper filtering or sanitization. This represents a fundamental flaw in the security architecture of the platform, where the system assumes all incoming SIP signaling data is valid and trustworthy. The vulnerability affects the core SIP processing functionality and can cause the CUCM service to become unresponsive, requiring manual intervention to restore normal operations. Security practitioners should note that this vulnerability operates at the application layer and can be detected through SIP traffic monitoring and anomaly detection systems. The lack of proper error handling means that the system cannot gracefully recover from malformed input, instead choosing to terminate or crash the affected service components. This makes the vulnerability particularly challenging to mitigate in environments where service availability is critical.
Organizations should immediately implement mitigation strategies including applying the relevant Cisco security patches and updates that address this specific vulnerability. The recommended solution involves upgrading to CUCM versions 5.1(2) or 6.1(1) where Cisco has implemented proper header validation and input sanitization mechanisms. Network administrators should also consider implementing SIP filtering rules and traffic monitoring to detect and block suspicious JOIN messages before they reach the vulnerable system. Additional defensive measures include configuring intrusion detection systems to identify patterns associated with this vulnerability and implementing rate limiting on SIP signaling traffic to prevent exploitation through automated attacks. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates the critical need for proper input validation in communication protocols. Organizations should also review their incident response procedures to ensure rapid detection and remediation of similar vulnerabilities. Security teams should conduct regular vulnerability assessments targeting SIP implementations and ensure proper network segmentation to limit the impact of potential exploitation. The remediation process should include comprehensive testing to verify that the patch does not introduce compatibility issues with existing communication services. This vulnerability underscores the necessity of robust security practices throughout the software development lifecycle, particularly in critical infrastructure components where service availability is paramount. The attack surface for this vulnerability extends beyond the immediate CUCM platform to include all systems that depend on its communication services, making comprehensive remediation essential for overall network security.