CVE-2015-6311 in Wireless LAN Controller
Summary
by MITRE
Cisco Wireless LAN Controller (WLC) devices with software 7.0(240.0), 7.3(101.0), and 7.4(1.19) allow remote attackers to cause a denial of service (device outage) by sending malformed 802.11i management data to a managed access point, aka Bug ID CSCub65236.
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Analysis
by VulDB Data Team • 06/20/2022
Cisco Wireless LAN Controller devices running specific software versions contain a critical vulnerability that enables remote attackers to trigger device outages through carefully crafted 802.11i management frames. This vulnerability specifically affects WLC software versions 7.0(240.0), 7.3(101.0), and 7.4(1.19) where the system fails to properly validate incoming management frames, leading to unexpected behavior and potential system crashes. The flaw resides in the wireless controller's processing of 802.11i management data packets, which are part of the standard IEEE 802.11i security protocol suite used for authentication and key management in wireless networks. When an attacker sends malformed management frames to a managed access point, the WLC device becomes unable to properly handle these packets, resulting in a denial of service condition that can bring the entire wireless infrastructure offline.
The technical implementation of this vulnerability demonstrates a classic buffer overflow or input validation flaw within the wireless controller's frame processing engine. The system lacks proper bounds checking and validation mechanisms when processing 802.11i management frames, allowing attackers to craft packets with malformed fields or unexpected data structures that cause the controller to enter an unstable state. This type of vulnerability maps directly to CWE-129, which describes improper validation of length of input data, and CWE-772, which covers missing release of resource after effective lifetime. The attack vector requires no authentication and can be executed from remote locations, making it particularly dangerous as it allows adversaries to disrupt wireless services without requiring physical access or network credentials. The impact extends beyond simple service disruption to potentially compromise the entire wireless network infrastructure, affecting enterprise connectivity, business operations, and user access to network resources.
The operational impact of CVE-2015-6311 represents a significant risk to enterprise wireless networks that rely on Cisco WLC devices for their infrastructure. Organizations utilizing affected software versions face potential business disruption from unauthorized denial of service attacks that can render wireless services unavailable for extended periods. The vulnerability creates a persistent threat vector that attackers can exploit repeatedly, potentially causing cascading failures throughout the wireless network topology as managed access points lose communication with the controller. From an adversary perspective, this vulnerability aligns with ATT&CK technique T1499.004, which describes network disruption through denial of service attacks, and T1046, which covers network service scanning to identify vulnerable systems. The attack can be automated and executed at scale, making it particularly attractive to threat actors seeking to disrupt operations or create diversionary attacks.
Organizations should immediately implement mitigation strategies including applying the latest security patches and firmware updates provided by Cisco to address the vulnerability. Network segmentation and monitoring should be enhanced to detect unusual 802.11i management frame traffic patterns that may indicate exploitation attempts. Access controls and authentication mechanisms should be strengthened to limit potential attack surfaces, while network administrators should implement intrusion detection systems capable of identifying malformed wireless management frames. The vulnerability also necessitates regular security assessments and vulnerability scanning to identify other potential weaknesses in the wireless infrastructure. Organizations should develop incident response procedures specifically addressing wireless denial of service attacks and maintain backup connectivity solutions to ensure business continuity during potential exploitation events. Continuous monitoring of Cisco security advisories and threat intelligence feeds remains essential for maintaining protection against similar vulnerabilities in the wireless networking infrastructure.