CVE-2021-34734 in Video Surveillance 7000
Summary
by MITRE • 08/19/2021
A vulnerability in the Link Layer Discovery Protocol (LLDP) implementation for the Cisco Video Surveillance 7000 Series IP Cameras firmware could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper management of memory resources, referred to as a double free. An attacker could exploit this vulnerability by sending crafted LLDP packets to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: LLDP is a Layer 2 protocol. To exploit these vulnerabilities, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).
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Analysis
by VulDB Data Team • 08/21/2021
The vulnerability identified as CVE-2021-34734 represents a critical denial of service weakness within the Cisco Video Surveillance 7000 Series IP Cameras firmware, specifically affecting the Link Layer Discovery Protocol implementation. This flaw manifests as a double free memory management error that occurs when the device processes malformed LLDP packets, creating a scenario where the system attempts to free the same memory block twice. The vulnerability resides in the Layer 2 network protocol handling mechanism, making it particularly concerning for surveillance deployments where network infrastructure security may be limited. According to CWE-415, this double free condition constitutes a classic memory corruption vulnerability that can lead to unpredictable system behavior and complete service interruption.
The operational impact of this vulnerability extends beyond simple service disruption as it enables an adjacent attacker to induce complete device reload cycles through carefully crafted LLDP packet transmission. This type of attack requires minimal privileges since no authentication is necessary, and the attacker only needs network proximity within the same broadcast domain to exploit the weakness. The attack vector specifically targets Layer 2 protocol processing, aligning with ATT&CK technique T1046 which describes network service scanning and exploitation of network protocols. The affected Cisco Video Surveillance 7000 Series IP Cameras represent high-value targets in security-critical environments where uninterrupted video monitoring is essential, making this DoS condition particularly dangerous as it can compromise surveillance operations and potentially provide cover for other attacks.
Mitigation strategies for CVE-2021-34734 should prioritize network segmentation and access control measures to prevent unauthorized adjacent network access to the affected devices. Implementing proper firewall rules and access control lists at Layer 2 can effectively isolate the surveillance network from general network traffic, reducing the attack surface. Network administrators should also consider disabling LLDP functionality on affected devices when it is not required for network operations, as this protocol is primarily used for device discovery and network management purposes. Additionally, regular firmware updates from Cisco should be implemented immediately upon availability, as the vendor has likely addressed this double free memory management issue in subsequent releases. The vulnerability's classification under CWE-415 emphasizes the need for robust memory management practices and proper input validation in network protocol implementations, particularly in embedded systems where resource constraints may lead to inadequate error handling mechanisms.