CVE-2018-0415 in Small Business 100 Series Wireless Access Point
Summary
by MITRE
A vulnerability in the implementation of Extensible Authentication Protocol over LAN (EAPOL) functionality in Cisco Small Business 100 Series Wireless Access Points and Cisco Small Business 300 Series Wireless Access Points could allow an authenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to the improper processing of certain EAPOL frames. An attacker could exploit this vulnerability by sending a stream of crafted EAPOL frames to an affected device. A successful exploit could allow the attacker to force the access point (AP) to disassociate all the associated stations (STAs) and to disallow future, new association requests. Cisco Bug IDs: CSCvj97472.
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Analysis
by VulDB Data Team • 03/16/2020
The vulnerability described in CVE-2018-0415 represents a critical denial of service weakness within Cisco's Small Business wireless access point line, specifically affecting the EAPOL implementation that governs authentication processes. This flaw resides in the wireless access point's handling of Extensible Authentication Protocol over LAN frames, which are fundamental to establishing secure network connections. The vulnerability is particularly concerning because it requires only adjacent network access, making it exploitable by attackers within the same physical network segment, and does not demand complex prerequisites beyond basic network connectivity. The affected devices include Cisco Small Business 100 Series and 300 Series Wireless Access Points, which are commonly deployed in small office environments where network security may be less rigorously managed.
The technical root cause of this vulnerability stems from improper processing of specific EAPOL frames that are normally handled as part of the standard authentication workflow. When an attacker sends a stream of crafted EAPOL frames to an affected access point, the device's implementation fails to properly validate or handle these malformed frames, leading to a cascading failure in the authentication system. This improper frame handling triggers a state machine anomaly within the EAPOL protocol implementation that ultimately results in the access point forcibly disassociating all currently connected wireless stations. The flaw manifests as a complete disruption of network services, where legitimate users lose connectivity and new devices cannot establish associations with the access point. This behavior aligns with CWE-129, which addresses improper validation of input boundaries, and specifically reflects weaknesses in protocol implementation that can lead to service disruption.
The operational impact of this vulnerability extends beyond simple network disruption, as it effectively renders the affected access point completely non-functional for its primary purpose of providing wireless network services. Once exploited, the access point enters a state where it cannot accept new association requests, creating a complete denial of service condition that requires manual intervention to resolve. The attack vector is particularly dangerous because it can be executed by any authenticated user within the physical network segment, meaning that insider threats or attackers who gain access to the local network can immediately compromise network availability. This vulnerability undermines the fundamental reliability of wireless network infrastructure in small business environments, where such access points often serve as the primary gateway for employee and customer connectivity. The exploit's simplicity and effectiveness make it a prime target for attackers seeking to disrupt business operations without requiring advanced technical skills or extensive resources.
Organizations should implement immediate mitigations including network segmentation to isolate wireless access points from general network traffic, enabling access control lists to restrict EAPOL frame processing, and deploying network monitoring solutions to detect anomalous EAPOL frame patterns. Network administrators should also ensure that access points are updated with the latest firmware releases that address this specific vulnerability, as Cisco has issued patches to resolve the EAPOL processing flaws. The mitigation strategy should incorporate regular network audits to identify and isolate vulnerable devices, along with implementing network intrusion detection systems that can identify the specific EAPOL frame patterns associated with this vulnerability. Additionally, organizations should consider implementing redundant wireless access points to minimize the impact of any single device compromise, and establish clear incident response procedures for handling such denial of service attacks. This vulnerability demonstrates the importance of secure protocol implementation in network infrastructure components and highlights the need for thorough security testing of authentication mechanisms that form the backbone of wireless network security.