CVE-2012-6371 in N900 Wireless Router
Summary
by MITRE
The WPA2 implementation on the Belkin N900 F9K1104v1 router establishes a WPS PIN based on 6 digits of the LAN/WLAN MAC address, which makes it easier for remote attackers to obtain access to a Wi-Fi network by reading broadcast packets, a different vulnerability than CVE-2012-4366.
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Analysis
by VulDB Data Team • 02/10/2018
The vulnerability described in CVE-2012-6371 represents a critical flaw in the WPA2 security implementation of the Belkin N900 F9K1104v1 router model. This issue specifically affects the Wi-Fi Protected Setup (WPS) functionality that is designed to simplify wireless network configuration for end users. The router's implementation of WPS PIN generation creates a predictable security weakness by deriving the PIN from only six digits of the router's MAC address, which is publicly broadcast in network packets. This design flaw fundamentally undermines the security assumptions that WPA2 and WPS are meant to provide, creating an exploitable condition that allows remote attackers to bypass normal authentication mechanisms.
The technical flaw stems from the insufficient entropy in the WPS PIN generation algorithm. According to CWE-331, this represents a weakness in randomness or entropy where the security mechanism fails to provide adequate unpredictability. The WPS PIN is intended to be a 8-digit number that provides approximately 100 million possible combinations, but by using only 6 digits from the MAC address, the effective search space is dramatically reduced to approximately 1 million possibilities. This reduction in complexity makes the PIN susceptible to brute force attacks, as attackers can simply capture the necessary broadcast packets and extract the MAC address information to narrow down the potential PIN combinations to a manageable subset.
The operational impact of this vulnerability extends beyond simple network access, as it creates a persistent security risk for all devices connected to the affected network. Attackers can perform passive reconnaissance by monitoring broadcast traffic, extracting the MAC address information, and then systematically testing the reduced PIN space to gain unauthorized access. This vulnerability operates under the ATT&CK framework's T1046 technique for network service scanning and T1075 for remote service exploitation, as it enables attackers to exploit weaknesses in wireless network authentication protocols. The ease of exploitation means that even unskilled attackers can potentially compromise networks without requiring sophisticated tools or techniques, making this a particularly dangerous vulnerability for enterprise and consumer networks alike.
Mitigation strategies for this vulnerability require immediate action to address the root cause of the WPS implementation flaw. Network administrators should disable WPS functionality entirely on affected routers, as this feature was designed for convenience rather than security and often introduces more vulnerabilities than it solves. The implementation of proper network segmentation and additional authentication layers can help reduce the impact if WPS cannot be disabled. Furthermore, regular firmware updates should be applied to ensure that newer versions address the predictable PIN generation issue. Organizations should also implement monitoring solutions that can detect unusual network access patterns and unauthorized device connections that might indicate successful exploitation attempts. The vulnerability highlights the importance of proper security design principles where convenience features should never compromise core security mechanisms, as outlined in security standards that emphasize the need for robust entropy in cryptographic implementations.