CVE-2017-3792 in TelePresence Multipoint Control Unit
Summary
by MITRE
A vulnerability in a proprietary device driver in the kernel of Cisco TelePresence Multipoint Control Unit (MCU) Software could allow an unauthenticated, remote attacker to execute arbitrary code or cause a denial of service (DoS) condition. The vulnerability is due to improper size validation when reassembling fragmented IPv4 or IPv6 packets. An attacker could exploit this vulnerability by sending crafted IPv4 or IPv6 fragments to a port receiving content in Passthrough content mode. An exploit could allow the attacker to overflow a buffer. If successful, the attacker could execute arbitrary code or cause a DoS condition on the affected system. Cisco TelePresence MCU platforms TelePresence MCU 5300 Series, TelePresence MCU MSE 8510 and TelePresence MCU 4500 are affected when running software version 4.3(1.68) or later configured for Passthrough content mode. Cisco has released software updates that address this vulnerability. Workarounds that address this vulnerability are not available, but mitigations are available. Cisco Bug IDs: CSCuu67675.
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Analysis
by VulDB Data Team • 08/28/2024
The vulnerability identified as CVE-2017-3792 represents a critical buffer overflow flaw within the kernel of Cisco TelePresence Multipoint Control Unit (MCU) devices, specifically affecting the reassembly process of fragmented internet protocol packets. This security weakness exists in the proprietary device driver responsible for handling network traffic in Passthrough content mode, creating a significant attack surface for remote adversaries. The flaw manifests when the system processes IPv4 or IPv6 packet fragments without proper size validation, allowing malicious actors to manipulate the packet reassembly mechanism and potentially execute arbitrary code or trigger denial of service conditions.
The technical implementation of this vulnerability stems from inadequate input validation during the packet fragmentation reassembly process, which directly corresponds to CWE-129, the weakness associated with insufficient size validation. When the MCU receives crafted fragmented packets, the device driver fails to properly verify the total size of reassembled packets against allocated buffer boundaries, creating an exploitable condition that can lead to memory corruption. This type of vulnerability falls under the ATT&CK technique T1059.007, where adversaries leverage system-level code execution through buffer overflow exploits, and represents a classic example of improper input validation that enables arbitrary code execution.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially compromise the entire system integrity, as remote attackers can gain unauthorized code execution privileges without authentication. The affected platforms include TelePresence MCU 5300 Series, MSE 8510, and 4500 models when operating in Passthrough content mode with software versions 4.3(1.68) or later. This configuration exposes organizations to significant risk since the vulnerability can be exploited over the network without requiring any credentials, making it particularly dangerous for video conferencing and collaboration environments where such devices are commonly deployed. The attack vector specifically targets network ports configured for Passthrough content mode, which is often used for direct media stream forwarding in telepresence systems.
Cisco has addressed this vulnerability through official software updates that correct the packet reassembly logic and implement proper size validation mechanisms. Organizations utilizing affected Cisco TelePresence MCU platforms should immediately apply these patches to mitigate the risk of exploitation. While no official workarounds are available for this specific vulnerability, network segmentation and access control measures can provide additional defense-in-depth strategies. The lack of available workarounds indicates the complexity of the issue, as the vulnerability resides at the kernel driver level where traditional network filtering approaches may not be sufficient. Security teams should monitor for potential exploitation attempts and implement network-based intrusion detection systems to identify suspicious fragmented packet patterns that could indicate exploitation attempts. The vulnerability highlights the importance of proper input validation in kernel-level network drivers and demonstrates how seemingly routine packet processing functions can become critical security gateways when insufficiently validated.