CVE-2008-1743 in Unified Communications Manager
Summary
by MITRE
Memory leak in the Certificate Trust List (CTL) Provider service in Cisco Unified Communications Manager (CUCM) 5.x before 5.1(3) and 6.x before 6.1(1) allows remote attackers to cause a denial of service (memory consumption and service interruption) via a series of malformed TCP packets, aka Bug ID CSCsi98433.
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Analysis
by VulDB Data Team • 08/10/2019
The vulnerability described in CVE-2008-1743 represents a critical memory leak issue within Cisco Unified Communications Manager's Certificate Trust List Provider service. This flaw exists in CUCM versions 5.x prior to 5.1(3) and 6.x prior to 6.1(1), affecting organizations that rely on Cisco's unified communications infrastructure for their voice and video conferencing needs. The vulnerability specifically targets the CTL Provider service which is responsible for managing certificate trust lists that validate the authenticity of digital certificates used in secure communications. This memory leak vulnerability demonstrates a fundamental flaw in how the system handles malformed network traffic, creating a pathway for remote attackers to exploit the service's resource management capabilities.
The technical implementation of this vulnerability stems from insufficient input validation within the CTL Provider service when processing TCP packets. Attackers can craft and transmit a series of malformed TCP packets to the affected CUCM service, causing the system to allocate memory resources without properly releasing them. This results in progressive memory consumption that eventually leads to system instability and service interruption. The vulnerability operates at the network protocol level, leveraging TCP packet handling mechanisms to trigger memory allocation failures that compound over time. The specific nature of the flaw suggests inadequate memory management practices within the service's packet processing code, where allocated memory blocks are not properly deallocated upon receipt of malformed data.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire unified communications infrastructure. Organizations relying on CUCM for mission-critical voice and video services face significant risk of operational downtime that can affect business continuity and communication capabilities. The memory leak effectuates a gradual degradation of system performance that may not be immediately apparent to administrators, making detection challenging until service interruption occurs. This vulnerability particularly affects enterprises that depend on secure communication protocols and certificate validation systems, as the CTL Provider service is integral to maintaining trust in digital certificate chains. The remote exploitation capability means that attackers do not require physical access or local network privileges to execute the attack, making it particularly dangerous for organizations with exposed network services.
Mitigation strategies for this vulnerability require immediate patch application to upgrade affected CUCM systems to versions 5.1(3) or 6.1(1) where the memory leak has been addressed. Network administrators should implement firewall rules and access control lists to restrict unnecessary TCP traffic to the affected service ports, reducing attack surface exposure. Monitoring systems should be enhanced to track memory consumption patterns and alert administrators to unusual resource usage that may indicate exploitation attempts. The vulnerability aligns with CWE-401 which addresses improper release of memory resources, and represents a classic example of how inadequate input validation can lead to resource exhaustion attacks. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique involving network denial of service attacks and demonstrates how memory management flaws can be leveraged for service interruption as part of broader attack strategies. Organizations should also consider implementing intrusion detection systems that can identify malformed TCP packet patterns commonly associated with this type of exploitation attempt.