CVE-2012-4694 in EDR-G903
Summary
by MITRE
Moxa EDR-G903 series routers with firmware before 2.11 do not use a sufficient source of entropy for (1) SSH and (2) SSL keys, which makes it easier for man-in-the-middle attackers to spoof a device or modify a client-server data stream by leveraging knowledge of a key from a product installation elsewhere.
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Analysis
by VulDB Data Team • 02/26/2018
The vulnerability identified as CVE-2012-4694 affects Moxa EDR-G903 series routers running firmware versions prior to 2.11, presenting a critical security weakness in the cryptographic implementation of these industrial networking devices. This flaw resides in the insufficient entropy sources used during the generation of cryptographic keys for both SSH and SSL protocols, creating predictable cryptographic material that significantly weakens the security posture of affected systems. The vulnerability is particularly concerning as it directly impacts the integrity and confidentiality of network communications that rely on these authentication and encryption mechanisms.
The technical flaw stems from the use of inadequate random number generation during cryptographic key creation processes. When cryptographic systems fail to utilize sufficient entropy sources, they produce predictable or reproducible keys that can be reverse-engineered by attackers. In this specific case, the Moxa routers generate SSH and SSL keys with insufficient randomness, making them vulnerable to attacks where adversaries can potentially reconstruct or predict key material. This weakness allows attackers to exploit the predictable nature of these keys to perform man-in-the-middle attacks, where they can impersonate legitimate devices or intercept and modify data streams between clients and servers.
The operational impact of this vulnerability extends beyond simple network security concerns to potentially compromise the integrity of industrial control systems and critical infrastructure communications. Attackers leveraging this weakness can gain unauthorized access to networked devices, potentially leading to system compromise, data exfiltration, or disruption of industrial processes. The vulnerability is particularly dangerous in environments where these routers serve as gateways for industrial networks, as it can enable attackers to move laterally within network segments and potentially access sensitive operational technology systems. The fact that keys generated on one device can be used to compromise similar installations elsewhere demonstrates the widespread nature of this weakness across deployments.
Mitigation strategies for CVE-2012-4694 should prioritize immediate firmware updates to version 2.11 or later, which address the insufficient entropy sources in cryptographic key generation. Organizations should also implement network segmentation and additional authentication controls to reduce the attack surface, while monitoring for suspicious network activity that might indicate exploitation attempts. Security professionals should consider implementing cryptographic key management solutions that can detect and alert on weak key generation patterns, and organizations should conduct thorough inventory assessments to identify all affected Moxa EDR-G903 devices across their network infrastructure. This vulnerability aligns with CWE-330, which describes insufficient entropy in random number generation, and represents a significant concern under ATT&CK technique T1566 related to credential harvesting through network sniffing and man-in-the-middle attacks.