CVE-2016-9219 in Wireless LAN Controller
Summary
by MITRE
A vulnerability with IPv6 UDP ingress packet processing in Cisco Wireless LAN Controller (WLC) Software could allow an unauthenticated, remote attacker to cause an unexpected reload of the device. The vulnerability is due to incomplete IPv6 UDP header validation. An attacker could exploit this vulnerability by sending a crafted IPv6 UDP packet to a specific port on the targeted device. An exploit could allow the attacker to impact the availability of the device as it could unexpectedly reload. This vulnerability affects Cisco Wireless LAN Controller (WLC) running software version 8.2.121.0 or 8.3.102.0. Cisco Bug IDs: CSCva98592.
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Analysis
by VulDB Data Team • 11/27/2022
The vulnerability described in CVE-2016-9219 represents a critical flaw in Cisco Wireless LAN Controller software that demonstrates the importance of proper network protocol validation in enterprise wireless infrastructure. This vulnerability specifically targets the IPv6 UDP ingress packet processing mechanism within the WLC software, exposing a fundamental weakness in how the system handles incoming network traffic. The issue manifests when the device receives malformed IPv6 UDP packets that bypass standard validation checks, creating a potential attack vector that could disrupt wireless network operations. The affected versions 8.2.121.0 and 8.3.102.0 indicate that this was a widespread issue affecting multiple release streams of the Cisco WLC software, highlighting the need for comprehensive security testing across different software versions. The vulnerability is classified under CWE-119, which deals with "Improper Restriction of Operations within the Bounds of a Memory Buffer," as it involves inadequate validation of packet headers that could lead to unexpected behavior in the system's memory handling.
The technical exploitation of this vulnerability requires an attacker to craft specific IPv6 UDP packets that trigger the incomplete header validation process within the WLC software. This type of attack aligns with ATT&CK technique T1499.002, which involves network denial of service attacks targeting network infrastructure devices. The crafted packets must be sent to specific ports on the targeted WLC device, making this a relatively precise attack vector that requires some knowledge of the target network configuration. The vulnerability's impact extends beyond simple service disruption, as the unexpected device reload could result in temporary loss of wireless connectivity for all connected clients, potentially affecting business operations and network availability. The fact that this vulnerability affects wireless network controllers means that successful exploitation could compromise the entire wireless infrastructure within an organization, potentially affecting thousands of wireless devices and users simultaneously.
The operational impact of CVE-2016-9219 is significant for organizations relying on Cisco WLC deployments, as it creates a potential single point of failure in wireless network infrastructure. When a device experiences an unexpected reload, all active wireless connections are disrupted, forcing users to reconnect to the network and potentially causing service interruptions that could last several minutes. This type of availability impact directly violates the principle of network resilience that organizations expect from their critical infrastructure components. The vulnerability's remote nature means that attackers do not require physical access to the device or network credentials to exploit it, making it particularly dangerous in environments where wireless networks are exposed to external threats. Organizations with multiple WLC deployments would face compounded risks, as the vulnerability could affect their entire wireless network estate if not properly addressed through software updates or network segmentation measures.
Mitigation strategies for this vulnerability should include immediate software patching to address the incomplete IPv6 UDP header validation issue, which would align with the remediation guidance typically provided by Cisco security advisories. Network administrators should implement proper firewall rules to restrict IPv6 traffic to WLC devices where possible, reducing the attack surface and preventing unauthorized access to the vulnerable ports. The implementation of intrusion detection systems that can monitor for malformed IPv6 UDP packets would provide additional layers of defense against exploitation attempts. Organizations should also consider network segmentation to isolate WLC devices from external networks, thereby limiting the potential attack vectors available to remote adversaries. The vulnerability highlights the importance of maintaining current security patches and conducting regular vulnerability assessments of critical network infrastructure components, as this issue could have been prevented through proper software maintenance and security monitoring practices. This case study serves as a reminder of the critical importance of validating all incoming network traffic, particularly in enterprise environments where network infrastructure devices serve as foundational components of organizational security posture.