CVE-2017-6790 in TelePresence Video Communication Server
Summary
by MITRE
A vulnerability in the Session Initiation Protocol (SIP) on the Cisco TelePresence Video Communication Server (VCS) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on the targeted appliance. The vulnerability is due to excessive SIP traffic sent to the device. An attacker could exploit this vulnerability by transmitting large volumes of SIP traffic to the VCS. An exploit could allow the attacker to cause a complete DoS condition on the targeted system. Cisco Bug IDs: CSCve32897.
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Analysis
by VulDB Data Team • 01/09/2021
The vulnerability identified as CVE-2017-6790 affects the Cisco TelePresence Video Communication Server (VCS) and represents a significant denial of service risk within enterprise communication infrastructure. This vulnerability specifically targets the Session Initiation Protocol implementation within the VCS appliance, which serves as a critical component in managing video conferencing sessions within organizations. The affected system operates as a central communication hub for Cisco's video conferencing solutions, making it a prime target for attackers seeking to disrupt business operations. The vulnerability manifests when the system receives an excessive volume of SIP traffic, which overwhelms the device's processing capabilities and results in complete service disruption. This type of attack directly impacts the availability aspect of the CIA triad, fundamentally compromising the system's ability to provide its intended services to legitimate users.
The technical flaw underlying CVE-2017-6790 stems from inadequate input validation and resource management within the SIP processing module of the Cisco VCS. When the system receives large volumes of SIP traffic, it fails to properly throttle or rate-limit incoming requests, leading to resource exhaustion and system instability. This vulnerability demonstrates a classic lack of proper traffic handling mechanisms that should be implemented to prevent resource exhaustion attacks. The flaw allows an attacker to exploit the absence of sufficient traffic monitoring and rate-limiting controls within the SIP processing pipeline, enabling them to flood the system with malformed or excessive SIP messages. The vulnerability is particularly concerning because it requires no authentication credentials to exploit, making it accessible to any remote attacker with network access to the targeted system. This unauthenticated nature aligns with common attack patterns documented in the MITRE ATT&CK framework under the initial access and execution phases, where attackers leverage publicly accessible services to establish footholds.
The operational impact of this vulnerability extends beyond simple service disruption to encompass broader business continuity concerns within organizations that rely heavily on video communication infrastructure. When the targeted VCS appliance experiences a complete denial of service condition, it affects all video conferencing capabilities within the organization, potentially disrupting critical business meetings, remote collaboration, and emergency communication protocols. The attack can result in significant productivity losses, as employees lose access to essential communication tools during peak business hours. Organizations may face additional costs related to system recovery, investigation of the security incident, and potential regulatory compliance issues if the disruption affects mission-critical operations. The vulnerability also exposes organizations to potential reputational damage when communication services are unavailable during important business events or client meetings. This type of vulnerability is classified as a resource exhaustion attack and corresponds to CWE-400, which addresses the improper handling of resources that can lead to denial of service conditions. The attack vector represents a common pattern in network security where attackers exploit protocol implementations to consume system resources beyond normal operational limits.
Mitigation strategies for CVE-2017-6790 should focus on implementing network-level protections and system hardening measures to prevent exploitation. Organizations should deploy network access control lists and firewall rules to limit SIP traffic to authorized sources only, implementing rate-limiting mechanisms to prevent traffic flooding. Cisco recommends applying the latest security patches and software updates to address the vulnerability, which typically include enhanced traffic monitoring and rate-limiting capabilities within the SIP processing module. Network administrators should implement monitoring solutions to detect unusual traffic patterns and establish automated alerting mechanisms when abnormal SIP traffic volumes are detected. The implementation of intrusion prevention systems can help identify and block malicious SIP traffic patterns before they can overwhelm the system. Additionally, organizations should consider implementing redundant communication infrastructure to maintain business continuity during potential attacks. The mitigation approach aligns with defensive techniques outlined in the MITRE ATT&CK framework under the defense evasion and persistence categories, where organizations implement controls to prevent exploitation of known vulnerabilities. Regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other network components that might be susceptible to analogous attacks, ensuring comprehensive protection across the entire communication infrastructure.