CVE-2016-9207 in TelePresence
Summary
by MITRE
A vulnerability in the HTTP traffic server component of Cisco Expressway could allow an unauthenticated, remote attacker to initiate TCP connections to arbitrary hosts. This does not allow for full traffic proxy through the Expressway. Affected Products: This vulnerability affects Cisco Expressway Series Software and Cisco TelePresence Video Communication Server (VCS). More Information: CSCvc10834. Known Affected Releases: X8.7.2 X8.8.3. Known Fixed Releases: X8.9.
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Analysis
by VulDB Data Team • 10/05/2022
The vulnerability identified as CVE-2016-9207 resides within the HTTP traffic server component of Cisco Expressway systems, representing a significant security weakness that enables unauthorized remote attackers to establish TCP connections to any host within the network infrastructure. This flaw specifically impacts Cisco Expressway Series Software and Cisco TelePresence Video Communication Server VCS platforms, creating a potential entry point for malicious actors seeking to expand their network reach without proper authentication credentials. The vulnerability operates at the network communication layer, exploiting the system's handling of HTTP traffic to create unintended connection pathways that bypass normal security controls.
The technical nature of this vulnerability stems from improper input validation and connection handling within the HTTP server implementation of the affected Cisco products. An attacker can leverage this weakness to initiate TCP connections to arbitrary hosts, effectively using the Expressway system as a relay point for network reconnaissance or attack propagation. While the vulnerability does not provide full proxy capabilities for all traffic, it does enable the attacker to establish connections to systems that would normally be restricted or protected by network segmentation policies. This behavior aligns with CWE-631: Improper Handling of Network Resources, which addresses weaknesses in how network resources are managed and validated. The flaw essentially allows for a form of network tunneling that can be used to probe internal systems or establish connections to services that should remain isolated from external access.
The operational impact of CVE-2016-9207 extends beyond simple network connectivity issues, as it creates opportunities for attackers to perform reconnaissance activities and potentially escalate their access within the network environment. An unauthenticated attacker could use this vulnerability to map internal network topology, identify open ports on internal systems, or even establish connections to vulnerable services that are not directly exposed to the internet. This capability represents a significant risk for organizations relying on Cisco Expressway systems for secure communications, as it undermines the network isolation that these systems are designed to provide. The vulnerability's exploitation does not require special privileges or credentials, making it particularly dangerous as it can be leveraged by anyone with access to the network where the affected system operates. From an attack methodology perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework under the T1071.004 sub-technique for Application Layer Protocol: Web Protocols, where attackers leverage legitimate network protocols to establish unauthorized connections.
Organizations affected by this vulnerability should prioritize immediate remediation through the installation of the fixed releases, specifically version X8.9, which addresses the underlying connection handling issues. The mitigation strategy should include comprehensive network monitoring to detect unauthorized TCP connection attempts originating from the affected systems, as well as reviewing and strengthening firewall rules to limit outbound connections from the Expressway servers. Network segmentation measures should be reinforced to ensure that even if an attacker exploits this vulnerability, they cannot easily move laterally within the network infrastructure. Additionally, organizations should implement network access controls that restrict the ability of the Expressway systems to initiate connections to arbitrary destinations, thereby limiting the potential impact of this vulnerability even if the primary fix cannot be immediately deployed. The vulnerability demonstrates the importance of proper input validation and resource management in network services, as highlighted in industry best practices for secure network architecture and the principles outlined in the NIST Cybersecurity Framework for protecting critical infrastructure components.