CVE-2018-0442 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 retrieve memory contents, which could lead to the disclosure of confidential information. The vulnerability is due to insufficient condition checks in the part of the code that handles CAPWAP keepalive requests. An attacker could exploit this vulnerability by sending a crafted CAPWAP keepalive packet to a vulnerable Cisco WLC device. A successful exploit could allow the attacker to retrieve the contents of device memory, which could lead to the disclosure of confidential information.
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Analysis
by VulDB Data Team • 05/30/2023
The vulnerability identified as CVE-2018-0442 resides within the Control and Provisioning of Wireless Access Points protocol implementation of Cisco Wireless LAN Controller software, representing a critical security weakness that affects network infrastructure devices. This flaw specifically manifests in the handling of CAPWAP keepalive requests, where inadequate input validation and condition checks create an exploitable condition that can be leveraged by remote attackers without authentication. The vulnerability impacts Cisco WLC devices running affected software versions, making it particularly concerning for organizations that rely on wireless network infrastructure for their operations. The issue stems from the protocol processing logic that fails to properly validate the structure and content of incoming CAPWAP keepalive messages, creating a path for memory disclosure attacks.
The technical exploitation of this vulnerability occurs through the manipulation of CAPWAP protocol communication channels that are essential for maintaining wireless access point connectivity to the central controller. Attackers can craft specially formatted CAPWAP keepalive packets that trigger the flawed memory handling code path within the WLC software. When processed, these malformed packets cause the system to expose portions of its memory contents through the protocol response mechanisms. This memory disclosure can reveal sensitive information including but not limited to configuration data, cryptographic keys, user credentials, and other confidential operational details that could be used to further compromise the network infrastructure. The vulnerability is particularly dangerous because it operates at the protocol level, allowing attackers to exploit the weakness without requiring any prior authentication or privileged access to the network.
The operational impact of CVE-2018-0442 extends beyond simple information disclosure, as the exposed memory contents can provide attackers with sufficient information to conduct more sophisticated attacks against the wireless infrastructure. Network administrators may find that the vulnerability allows for complete compromise of wireless network security, potentially enabling attackers to gain unauthorized access to wireless clients, intercept wireless communications, or manipulate wireless access point configurations. The remote nature of the exploit means that attackers can target vulnerable devices from anywhere on the network, making the attack surface extremely broad and difficult to contain. Organizations may experience significant operational disruption as attackers can use the disclosed information to escalate privileges, conduct man-in-the-middle attacks, or launch additional attacks against other network components that share the same infrastructure.
Mitigation strategies for this vulnerability should focus on immediate software updates and network segmentation measures to reduce the attack surface. Cisco has released patches and software updates to address this issue, which should be applied immediately to all affected WLC devices within the network infrastructure. Network administrators should also implement monitoring solutions that can detect anomalous CAPWAP traffic patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-125, which describes out-of-bounds read conditions in software implementations, and represents a classic example of how protocol implementation flaws can create information disclosure vulnerabilities. From an ATT&CK framework perspective, this vulnerability maps to techniques involving credential access and defense evasion, as attackers can use the disclosed information to maintain persistence and avoid detection while conducting reconnaissance activities. Organizations should also consider implementing network access controls and firewall rules that limit CAPWAP traffic to trusted sources only, and conduct thorough network assessments to identify all potentially affected devices.