CVE-2016-8712 in AWK-3131A
Summary
by MITRE
An exploitable nonce reuse vulnerability exists in the Web Application functionality of Moxa AWK-3131A Wireless AP running firmware 1.1. The device uses one nonce for all session authentication requests and only changes the nonce if the web application has been idle for 300 seconds.
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Analysis
by VulDB Data Team • 11/29/2022
The CVE-2016-8712 vulnerability represents a critical session management flaw in Moxa AWK-3131A Wireless Access Points running firmware version 1.1. This device operates as a web-based management interface for industrial networking equipment, making it a prime target for attackers seeking unauthorized access to critical infrastructure. The vulnerability stems from a fundamental flaw in the authentication mechanism where the system employs a static nonce value across all session authentication requests. A nonce, by design, should be unique for each authentication attempt to prevent replay attacks and ensure session integrity. The implementation in this device fails to generate fresh nonces for each session, creating a persistent security weakness that can be exploited by malicious actors.
The technical exploitation of this vulnerability relies on the predictable nature of the nonce reuse pattern. When an attacker observes a valid authentication session token, they can reuse the same nonce value to forge authentication requests without needing to know the actual credentials. This flaw directly violates the principles outlined in CWE-310, which addresses cryptographic weaknesses in nonce usage and session management. The device's behavior of changing the nonce only after 300 seconds of inactivity creates a window of opportunity where attackers can capture valid session tokens and reuse them within the brief period before the nonce refresh occurs. This vulnerability essentially eliminates the cryptographic protection that should prevent replay attacks, making the authentication system fundamentally insecure.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential industrial control system compromise. The Moxa AWK-3131A serves as a wireless access point for industrial environments where network security is paramount, and unauthorized access could lead to disruption of critical operations or data breaches. Attackers can leverage this vulnerability to gain persistent access to the device management interface, potentially enabling them to modify network configurations, access sensitive data, or establish backdoor access points. The vulnerability also aligns with ATT&CK technique T1566, which covers credential harvesting through social engineering or exploitation of weak authentication mechanisms, and T1071, which addresses application layer protocol usage for command and control communications. The long idle period before nonce rotation means that even brief network monitoring sessions could provide sufficient time for attackers to capture and reuse valid authentication tokens.
Mitigation strategies for CVE-2016-8712 require immediate firmware updates from Moxa to address the nonce reuse implementation. Network administrators should implement additional security controls such as network segmentation to isolate these devices from critical systems and deploy intrusion detection systems to monitor for unauthorized access attempts. The device should be configured with strong authentication mechanisms including multi-factor authentication where possible, and regular security audits should be conducted to verify proper implementation of session management controls. Organizations should also consider implementing network access control policies that limit direct web access to these devices and instead rely on secure management protocols such as SSH or encrypted VPN connections for administrative access. This vulnerability underscores the importance of proper session management implementation and serves as a reminder that industrial network equipment requires the same rigorous security considerations as other critical infrastructure components.