CVE-2018-0443 in Wireless LAN Controller
Summary
by MITRE
A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol component of Cisco Wireless LAN Controller (WLC) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to improper input validation on fields within CAPWAP Discovery Request packets by the affected device. An attacker could exploit this vulnerability by sending malicious CAPWAP Discovery Request packets to the Cisco WLC Software. A successful exploit could allow the attacker to cause the Cisco WLC Software to disconnect associated access points (APs). While the APs disconnect and reconnect, service will be unavailable for a brief period of time, resulting in a DoS condition.
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Analysis
by VulDB Data Team • 05/30/2023
The vulnerability identified as CVE-2018-0443 affects the Control and Provisioning of Wireless Access Points protocol implementation within Cisco Wireless LAN Controller software, representing a critical security flaw that enables remote attackers to disrupt wireless network operations. This issue stems from inadequate input validation mechanisms within the CAPWAP Discovery Request packet processing functionality, which serves as a fundamental communication protocol between wireless access points and wireless controllers in enterprise wireless networks. The vulnerability specifically targets the validation of fields within CAPWAP Discovery Request packets, creating an exploitable condition that can be leveraged by unauthenticated attackers positioned on the network.
The technical flaw manifests when the affected Cisco WLC software receives malformed CAPWAP Discovery Request packets that contain improperly validated data fields. These packets are typically used during the initial discovery phase where access points announce their presence to the wireless controller and establish communication channels. The insufficient validation allows attackers to craft malicious packets that trigger unexpected behavior in the controller's processing logic, leading to service disruption. According to CWE classification, this vulnerability corresponds to CWE-20: Improper Input Validation, which represents a common weakness pattern that occurs when software does not properly validate input data before processing it, creating opportunities for attackers to manipulate system behavior through crafted inputs.
From an operational impact perspective, successful exploitation of CVE-2018-0443 results in a denial of service condition that affects wireless network availability and service continuity. When an attacker successfully sends malicious CAPWAP Discovery Request packets, the wireless controller becomes unable to maintain stable connections with associated access points, causing them to disconnect and subsequently reconnect to the network. This disruption creates temporary service outages that can significantly impact enterprise operations, particularly in environments where wireless connectivity is critical for business processes. The DoS condition affects the entire wireless infrastructure managed by the compromised controller, potentially impacting thousands of connected devices and users across the network.
The vulnerability aligns with several tactics, techniques, and procedures documented in the MITRE ATT&CK framework, specifically relating to initial access and privilege escalation through network service exploitation. Attackers can leverage this vulnerability without requiring authentication credentials, making it particularly dangerous as it can be exploited from any network location where the attacker has network access. The attack vector involves crafting and transmitting malicious CAPWAP packets, which falls under network protocol manipulation techniques. Organizations implementing wireless infrastructure security measures should consider this vulnerability when developing their security posture, as it represents a critical weakness that can be exploited to compromise network availability and service delivery.
Effective mitigation strategies for CVE-2018-0443 include applying the relevant Cisco security patches and updates that address the input validation flaws in CAPWAP packet processing. Network administrators should implement network segmentation and access control measures to limit exposure of wireless controllers to untrusted networks, reducing the attack surface available to potential attackers. Additionally, monitoring network traffic for anomalous CAPWAP Discovery Request patterns can help detect exploitation attempts before they cause significant disruption. Organizations should also consider implementing intrusion detection systems that can identify and alert on suspicious CAPWAP protocol traffic patterns, providing early warning capabilities for potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation in network protocol implementations and highlights the critical need for robust security testing of network infrastructure components to prevent similar issues from occurring in the future.