CVE-2007-4011 in Wireless LAN Controller
Summary
by MITRE
Cisco 4100 and 4400, Airespace 4000, and Catalyst 6500 and 3750 Wireless LAN Controller (WLC) software before 3.2 20070727, 4.0 before 20070727, and 4.1 before 4.1.180.0 allows remote attackers to cause a denial of service (traffic amplification or ARP storm) via a crafted unicast ARP request that (1) has a destination MAC address unknown to the Layer-2 infrastructure, aka CSCsj69233; or (2) occurs during Layer-3 roaming across IP subnets, aka CSCsj70841.
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Analysis
by VulDB Data Team • 07/22/2019
This vulnerability affects Cisco wireless LAN controllers including the 4100 and 4400 series, Airespace 4000, and Catalyst 6500 and 3750 models running software versions prior to specific patches released in July 2007. The flaw manifests as a remote denial of service condition that can be exploited through crafted ARP requests, creating traffic amplification effects or generating ARP storms that overwhelm network infrastructure. The vulnerability is categorized under CWE-121 as a buffer overflow condition, though the specific implementation involves improper handling of Layer-2 and Layer-3 network protocols rather than traditional memory corruption. The attack vectors leverage fundamental network communication mechanisms that are essential for device discovery and network connectivity, making the exploitation particularly dangerous in enterprise environments where wireless infrastructure is critical for operations.
The technical implementation of this vulnerability occurs when the wireless controller receives specially crafted unicast ARP requests that either contain destination MAC addresses not recognized by the Layer-2 infrastructure or when ARP requests are processed during Layer-3 roaming scenarios across different IP subnets. In the first scenario, the controller attempts to forward the ARP request to a non-existent MAC address, causing it to generate multiple responses or broadcast traffic that amplifies the original request. In the second scenario, during Layer-3 roaming operations, the controller's ARP handling logic fails to properly validate or process the request, leading to excessive traffic generation. This behavior maps to ATT&CK technique T1498.001 which involves network denial of service attacks that amplify network traffic to overwhelm systems. The vulnerability specifically impacts the controller's ability to process Layer-2 forwarding decisions and Layer-3 routing operations, causing the device to become unresponsive or consume excessive resources.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire wireless network segments and create cascading failures within enterprise infrastructure. When exploited, the traffic amplification effects can saturate network links between the wireless controller and upstream network devices, effectively cutting off wireless access for all connected clients. During Layer-3 roaming scenarios, the ARP storm conditions can cause the controller to become unresponsive, forcing network administrators to manually restart services or replace affected hardware. The vulnerability affects critical enterprise infrastructure components that support business operations, making it particularly dangerous in environments where wireless connectivity is essential for productivity. Organizations may experience extended downtime as network teams must identify affected devices, implement temporary workarounds, and apply patches across their wireless infrastructure.
Mitigation strategies for this vulnerability require immediate patching of affected Cisco wireless controllers with software versions released in July 2007, specifically targeting the 3.2, 4.0, and 4.1 software releases. Network administrators should implement ARP inspection and filtering mechanisms at Layer-2 boundaries to prevent malformed ARP requests from reaching the wireless controllers. The implementation of rate limiting on ARP request processing and monitoring for unusual ARP traffic patterns can help detect exploitation attempts. Organizations should also consider implementing network segmentation to isolate wireless infrastructure from critical network segments and establish automated monitoring systems that can detect traffic amplification patterns. Additionally, network engineers should review and test the impact of patches on existing wireless deployments before applying updates to ensure continued functionality of wireless services. This vulnerability demonstrates the importance of maintaining up-to-date network infrastructure and implementing robust network monitoring to detect anomalous behavior that could indicate exploitation attempts.