CVE-2018-0409 in Unified Communications Manager IM
Summary
by MITRE
A vulnerability in the XCP Router service of the Cisco Unified Communications Manager IM & Presence Service (CUCM IM&P) and the Cisco TelePresence Video Communication Server (VCS) and Expressway could allow an unauthenticated, remote attacker to cause a temporary service outage for all IM&P users, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending a malicious IPv4 or IPv6 packet to an affected device on TCP port 7400. An exploit could allow the attacker to overread a buffer, resulting in a crash and restart of the XCP Router service. Cisco Bug IDs: CSCvg97663, CSCvi55947.
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Analysis
by VulDB Data Team • 05/02/2023
The vulnerability identified as CVE-2018-0409 represents a critical denial of service weakness within Cisco's unified communications infrastructure, specifically affecting the XCP Router service component. This flaw exists in both the Cisco Unified Communications Manager IM & Presence Service and the Cisco TelePresence Video Communication Server along with Expressway platforms. The vulnerability stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data, creating an exploitable condition that can be leveraged by remote attackers without authentication. The affected service operates on TCP port 7400, making it accessible to anyone capable of sending network traffic to the targeted device, which significantly broadens the potential attack surface and threat vector.
The technical exploitation of this vulnerability involves sending specifically crafted IPv4 or IPv6 packets to the targeted Cisco device, which triggers a buffer overread condition within the XCP Router service. This improper input validation allows attackers to manipulate the service's memory handling mechanisms, causing the application to read beyond allocated buffer boundaries and ultimately leading to a service crash and automatic restart. The buffer overread occurs during the processing of malformed packets that are sent to the vulnerable TCP port, where the service fails to validate the length or content of incoming data before attempting to process it. This memory corruption results in the XCP Router service crashing and subsequently restarting, which creates a temporary disruption in service availability for all IM&P users. The vulnerability specifically affects the XCP Router service implementation, which is responsible for handling communication routing within the unified communications framework, making it a critical component for maintaining service continuity.
The operational impact of this vulnerability extends beyond simple service disruption, as it affects the core functionality of Cisco's unified communications infrastructure, particularly impacting instant messaging and presence services that are fundamental to enterprise communication systems. The DoS condition affects all users within the IM&P service scope, potentially disrupting business operations and communication workflows across organizations that depend on these services for collaboration and coordination. The temporary nature of the service outage, while not permanently compromising system integrity, creates significant operational challenges for enterprises relying on continuous communication services. Organizations may experience disruptions in critical business processes that depend on real-time messaging and presence information, leading to productivity losses and potential service-level agreement violations. The vulnerability's ability to cause service restarts also introduces additional operational concerns, as repeated exploitation attempts could lead to sustained service degradation or even complete service unavailability during attack periods.
Mitigation strategies for this vulnerability should focus on immediate network-level protections combined with proper software updates and configuration hardening measures. Cisco has released patches addressing this vulnerability through their security advisory process, and organizations should prioritize applying these updates to affected systems. Network segmentation and access control measures should be implemented to restrict access to TCP port 7400, particularly from untrusted networks, and firewall rules should be configured to limit exposure to only authorized sources. The implementation of intrusion detection systems can help identify and alert on suspicious traffic patterns targeting the vulnerable port, while monitoring should be enhanced to detect service restarts that may indicate exploitation attempts. Additionally, organizations should consider implementing rate limiting or packet filtering mechanisms to prevent the delivery of malformed packets that could trigger the buffer overread condition. From a compliance perspective, this vulnerability aligns with CWE-129, which addresses improper validation of input boundaries, and represents a significant concern under ATT&CK technique T1499.002 for network denial of service attacks. The vulnerability demonstrates the importance of input validation and proper memory management in network services, as highlighted by industry best practices for secure software development and the need for robust defensive measures against remote exploitation vectors in enterprise communication infrastructure.