CVE-2017-12280 in Wireless LAN Controller
Summary
by MITRE
A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) Discovery Request parsing functionality of Cisco Wireless LAN Controllers could allow an unauthenticated, remote attacker to cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to incomplete input validation of fields in CAPWAP Discovery Request packets by the affected device. An attacker could exploit this vulnerability by sending crafted CAPWAP Discovery Request packets to an affected device. A successful exploit could allow the attacker to cause the affected device to restart unexpectedly, resulting in a DoS condition. Cisco Bug IDs: CSCvb95842.
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Analysis
by VulDB Data Team • 01/21/2021
The vulnerability identified as CVE-2017-12280 resides within Cisco's Wireless LAN Controller implementation of the Control and Provisioning of Wireless Access Points CAPWAP protocol, specifically affecting the Discovery Request parsing functionality. This flaw represents a critical security weakness that undermines the availability of wireless infrastructure by enabling unauthorized disruption of network services. The vulnerability impacts Cisco Wireless LAN Controllers that process CAPWAP Discovery Requests, which are fundamental components in wireless network deployment and management, facilitating communication between wireless access points and their controllers. The affected devices operate under the assumption that incoming CAPWAP Discovery Requests contain valid and properly formatted data, creating an attack surface where malformed packets can trigger unexpected behavior. This issue particularly affects enterprise wireless networks where uninterrupted access to wireless services is paramount for business operations and user productivity.
The technical root cause of this vulnerability stems from incomplete input validation mechanisms within the CAPWAP Discovery Request processing code. When an affected Cisco Wireless LAN Controller receives a CAPWAP Discovery Request packet, it fails to adequately validate certain fields within the packet structure, specifically those related to the discovery process parameters. This incomplete validation allows crafted packets containing malformed or unexpected data to bypass normal parsing routines and potentially trigger memory corruption or resource management issues within the controller's processing stack. The vulnerability manifests when the controller attempts to parse specific fields in the CAPWAP Discovery Request that contain values outside the expected range or format, leading to unpredictable behavior that ultimately results in system instability. According to the Cisco Bug ID CSCvb95842, the flaw occurs during the packet parsing phase where the system does not properly sanitize input before proceeding with further processing, creating a condition where malformed data can cause the device to crash or restart. This type of vulnerability aligns with CWE-20, which describes "Improper Input Validation" as a common weakness in software systems where inputs are not properly validated, leading to various security implications.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the integrity of enterprise wireless networks and business continuity operations. An unauthenticated remote attacker can exploit this weakness from any location with network access to the affected wireless controller, making it particularly dangerous as it requires no credentials or physical access to the device. The resulting denial of service condition effectively renders the wireless infrastructure unavailable to legitimate users, potentially impacting thousands of connected devices and users within the affected network segment. This vulnerability is especially concerning for organizations that rely heavily on wireless connectivity for critical business functions, such as healthcare facilities, financial institutions, or manufacturing environments where wireless networks support essential operational processes. The DoS condition can persist until manual intervention occurs, requiring network administrators to restart the affected controllers, which may take significant time and could compound business disruption during critical periods. Organizations with multiple wireless controllers may face cascading failures if the attack is not properly contained, as the DoS condition affects the entire wireless infrastructure rather than individual access points.
Mitigation strategies for this vulnerability should focus on both immediate protective measures and long-term architectural improvements to prevent exploitation. Network administrators should implement immediate network segmentation and access controls to limit exposure of wireless controllers to untrusted networks, particularly by ensuring that CAPWAP traffic is properly filtered at network boundaries. Cisco recommends applying the latest security patches and software updates that address this specific vulnerability, as the company has released firmware updates that correct the input validation issues in the CAPWAP Discovery Request processing code. Organizations should also consider implementing network monitoring solutions that can detect unusual CAPWAP traffic patterns or malformed packets that may indicate exploitation attempts. The implementation of intrusion detection systems capable of identifying and blocking suspicious CAPWAP Discovery Request packets represents a valuable defensive measure. Additionally, network administrators should review and tighten access controls for wireless controllers, ensuring that only authorized personnel have administrative access and that network access controls are properly configured to prevent unauthorized network access to these critical devices. This vulnerability demonstrates the importance of applying security patches promptly and maintaining updated network infrastructure to protect against known weaknesses in wireless protocols and implementations. The ATT&CK framework categorizes this type of vulnerability under network service disruption techniques, where adversaries leverage protocol implementation flaws to compromise availability. Organizations should also consider implementing redundant wireless infrastructure to provide failover capabilities during potential exploitation events, ensuring business continuity even when primary wireless services are temporarily disrupted.