CVE-2016-6375 in Wireless LAN Controller
Summary
by MITRE
Cisco Wireless LAN Controller (WLC) devices before 8.0.140.0, 8.1.x and 8.2.x before 8.2.121.0, and 8.3.x before 8.3.102.0 allow remote attackers to cause a denial of service (device reload) by sending crafted Inter-Access Point Protocol (IAPP) packets and then sending a traffic stream metrics (TSM) information request over SNMP, aka Bug ID CSCuz40221.
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Analysis
by VulDB Data Team • 09/15/2022
The vulnerability described in CVE-2016-6375 represents a critical denial of service weakness affecting Cisco Wireless LAN Controller devices across multiple software versions. This flaw specifically targets the Inter-Access Point Protocol implementation within the wireless infrastructure, creating a pathway for remote attackers to disrupt network operations through carefully crafted network packets. The vulnerability impacts devices running firmware versions prior to 8.0.140.0, 8.1.x series, 8.2.x series before 8.2.121.0, and 8.3.x series before 8.3.102.0, making it a widespread concern for enterprise wireless network administrators. The flaw operates through a combination of IAPP packet manipulation followed by SNMP TSM information requests, creating a cascading effect that ultimately forces device reloads and service disruption.
The technical mechanism behind this vulnerability involves the improper handling of Inter-Access Point Protocol messages within the Cisco WLC software stack. When maliciously crafted IAPP packets are received by the affected devices, they trigger an internal processing error that becomes exacerbated when subsequent SNMP traffic containing TSM information requests is processed. This combination creates a condition where the device's memory management or state handling mechanisms become corrupted, leading to an automatic device restart or reload. The vulnerability demonstrates characteristics consistent with CWE-121, heap-based buffer overflow conditions, where insufficient validation of input data leads to memory corruption. The attack vector requires only network access to the affected device, making it particularly dangerous as it can be exploited remotely without requiring physical access or authentication credentials.
From an operational perspective, this vulnerability poses significant risk to enterprise wireless networks as it can be leveraged to create sustained service disruptions without requiring advanced technical skills or privileged access. The device reload caused by this vulnerability effectively removes the wireless access point from service, potentially affecting hundreds or thousands of connected devices depending on the network size and configuration. Network availability is severely impacted as the affected controllers must be manually restarted or may automatically recover, but during the downtime period, all wireless services provided by those controllers become unavailable. This type of attack aligns with ATT&CK technique T1499.002, which describes network denial of service attacks that target network infrastructure components to prevent legitimate users from accessing services.
Organizations affected by this vulnerability should implement immediate mitigation strategies including applying the relevant Cisco security patches and firmware updates to bring their devices to supported versions. Network segmentation and access control measures should be strengthened to limit exposure of wireless controllers to untrusted networks, while monitoring systems should be configured to detect anomalous IAPP traffic patterns. The implementation of SNMP access controls and restrictions on TSM information requests can help reduce the attack surface. Additionally, network administrators should consider implementing intrusion detection systems that can identify and alert on suspicious IAPP packet sequences and SNMP traffic patterns that may indicate exploitation attempts. Regular vulnerability assessments and security audits should be conducted to ensure all wireless infrastructure components remain up to date with the latest security patches and configuration best practices.