CVE-2015-4144 in hostapd
Summary
by MITRE
The EAP-pwd server and peer implementation in hostapd and wpa_supplicant 1.0 through 2.4 does not validate that a message is long enough to contain the Total-Length field, which allows remote attackers to cause a denial of service (crash) via a crafted message.
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Analysis
by VulDB Data Team • 05/21/2022
The vulnerability identified as CVE-2015-4144 affects the EAP-pwd authentication implementation within hostapd and wpa_supplicant versions 1.0 through 2.4. This issue resides in the Extensible Authentication Protocol over Password (EAP-pwd) protocol implementation which is designed to provide secure password-based authentication for wireless networks. The flaw manifests in the server and peer components that process EAP-pwd messages during the authentication handshake process. According to the Common Weakness Enumeration standard CWE-129, this represents an input validation weakness where insufficient checks are performed on message length parameters. The vulnerability specifically targets the Total-Length field within EAP-pwd messages, which serves as a critical indicator of message integrity and proper formatting.
The technical execution of this vulnerability occurs when the EAP-pwd implementation fails to validate that incoming messages contain sufficient data to accommodate the Total-Length field as defined in the protocol specification. This validation gap allows malicious actors to craft specially formatted EAP-pwd messages that deliberately lack the required minimum length to contain the Total-Length field. When the vulnerable software processes such malformed messages, it attempts to read the Total-Length field from an insufficiently sized buffer, leading to memory access violations and subsequent application crashes. This behavior aligns with the ATT&CK technique T1499.004 which describes denial of service through resource exhaustion and memory corruption attacks. The vulnerability is particularly concerning because it operates at the network protocol level, allowing remote attackers to trigger the denial of service condition without requiring authentication or physical access to the target system.
The operational impact of CVE-2015-4144 extends beyond simple service disruption to potentially compromise the entire wireless authentication infrastructure. When exploited successfully, the vulnerability can cause complete service outages for wireless networks relying on EAP-pwd authentication, affecting thousands of users who depend on these networks for connectivity. Network administrators may experience extended downtime while investigating and resolving the service interruptions, leading to productivity losses and potential security implications. The vulnerability affects both the authentication server (hostapd) and client supplicant (wpa_supplicant) components, meaning that either side of the wireless authentication exchange could be targeted. Organizations using wireless networks for critical operations, such as healthcare facilities, financial institutions, or industrial control systems, face particularly severe consequences from this vulnerability. The attack surface is broad as it affects any wireless infrastructure implementing EAP-pwd authentication, making it a significant concern for enterprise wireless network deployments.
Mitigation strategies for CVE-2015-4144 focus primarily on immediate software updates and patches provided by the maintainers of hostapd and wpa_supplicant. The most effective solution involves upgrading to versions that contain the specific fix for the message length validation issue, typically found in hostapd and wpa_supplicant version 2.5 and later. Network administrators should implement a comprehensive patch management process to ensure all wireless infrastructure components are updated promptly. Additional defensive measures include network segmentation to limit the exposure of vulnerable systems, implementing intrusion detection systems to monitor for malformed EAP-pwd traffic patterns, and configuring access control lists to restrict EAP-pwd message processing from untrusted network segments. Security monitoring should include detection of unusual authentication failure patterns and abnormal message sizes that could indicate exploitation attempts. Organizations should also consider implementing alternative authentication methods such as EAP-TLS or EAP-PEAP to reduce dependency on the vulnerable EAP-pwd implementation while patches are deployed. The vulnerability demonstrates the critical importance of proper input validation in network protocol implementations and serves as a reminder of the potential for seemingly minor protocol parsing issues to result in significant security incidents.