CVE-2007-2039 in Wireless LAN Controller
Summary
by MITRE
The Network Processing Unit (NPU) in the Cisco Wireless LAN Controller (WLC) before 3.2.171.5, 4.0.x before 4.0.206.0, and 4.1.x allows remote attackers on a local wireless network to cause a denial of service (loss of packet forwarding) via (1) crafted SNAP packets, (2) malformed 802.11 traffic, or (3) packets with certain header length values, aka Bug IDs CSCsg15901 and CSCsh10841.
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Analysis
by VulDB Data Team • 07/14/2021
The vulnerability identified as CVE-2007-2039 affects the Network Processing Unit within Cisco Wireless LAN Controllers, specifically impacting versions prior to 3.2.171.5, 4.0.x before 4.0.206.0, and 4.1.x before 4.1.206.0. This flaw represents a critical denial of service vulnerability that compromises the packet forwarding capabilities of wireless networks, fundamentally undermining the availability and operational integrity of wireless infrastructure. The vulnerability manifests through three distinct attack vectors involving crafted SNAP packets, malformed 802.11 traffic, and packets containing specific header length values, making it particularly challenging to defend against as it can be exploited through multiple entry points. The impact extends beyond simple network disruption to potentially compromising the entire wireless infrastructure's ability to forward packets, which directly affects business continuity and wireless network reliability for organizations relying on Cisco WLC solutions.
The technical implementation of this vulnerability stems from inadequate input validation and error handling within the NPU's packet processing mechanisms. When the wireless controller receives malformed or specially crafted packets, the NPU fails to properly handle these inputs, leading to a complete loss of packet forwarding functionality. This behavior aligns with CWE-129, Input Validation, and CWE-248, Uncaught Exception, as the system does not properly validate incoming packet structures or handle unexpected packet formats. The vulnerability operates at the network protocol level, specifically targeting the 802.11 wireless frame processing capabilities of the controller, which places it within the scope of wireless security protocols and network infrastructure vulnerabilities. The attack vectors leverage the fundamental packet processing capabilities of the wireless controller, making this a systemic weakness rather than an isolated component failure.
From an operational perspective, this vulnerability presents a significant risk to enterprise wireless networks as it allows remote attackers positioned on the same local wireless network to completely disrupt network connectivity without requiring authentication or privileged access. The attack can be executed by simply transmitting specially crafted packets to the wireless controller, making it particularly dangerous in environments where wireless networks are exposed to untrusted users or where physical access to the wireless infrastructure is not properly controlled. The impact extends beyond individual network segments to potentially affect large enterprise wireless deployments, as the loss of packet forwarding capabilities can cascade through the entire wireless infrastructure. Organizations may experience complete wireless service outages, requiring manual intervention to restore normal operations, which can result in significant business disruption and productivity loss. This vulnerability directly maps to the ATT&CK technique T1499.002, Network Denial of Service, and T1566.002, Phishing via Service, as attackers can exploit the wireless infrastructure without requiring complex authentication processes.
The mitigation strategies for this vulnerability involve immediate software patching to the affected Cisco WLC versions, with administrators required to upgrade to the patched versions to eliminate the risk. Additionally, network segmentation and access control measures should be implemented to limit the exposure of wireless controllers to untrusted wireless networks, while monitoring systems should be deployed to detect anomalous packet patterns that may indicate exploitation attempts. Organizations should also consider implementing network access control policies that restrict wireless access to authorized devices and users only, reducing the attack surface available to potential attackers. The vulnerability highlights the importance of regular security updates and patch management processes, particularly for critical network infrastructure components. Security teams should conduct thorough network assessments to identify all affected wireless controllers and implement comprehensive monitoring to detect potential exploitation attempts, while also developing incident response procedures specifically addressing wireless denial of service attacks. This vulnerability serves as a reminder of the critical importance of input validation and proper error handling in network infrastructure devices, as the failure to properly validate packet structures can lead to complete service disruption and compromise of network availability.