CVE-2012-3039 in Oncell Gateway G3211
Summary
by MITRE
Moxa OnCell Gateway G3111, G3151, G3211, and G3251 devices with firmware before 1.4 do not use a sufficient source of entropy for SSH and SSL keys, which makes it easier for remote attackers to obtain access 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-2012-3039 affects Moxa OnCell Gateway series devices including models G3111, G3151, G3211, and G3251. These industrial networking devices operate in critical infrastructure environments where secure remote access is essential for maintenance and monitoring operations. The flaw resides in the cryptographic implementation of SSH and SSL protocols within the device firmware, specifically in the entropy sources used for generating cryptographic keys. This weakness creates a predictable cryptographic environment that significantly undermines the security posture of these network appliances.
The technical root cause of this vulnerability stems from insufficient entropy sources during the key generation process for SSH and SSL cryptographic protocols. Entropy represents the randomness or unpredictability that cryptographic systems require to generate secure keys. When entropy is inadequate or predictable, cryptographic key generation becomes vulnerable to various attacks including brute force attempts and statistical analysis. In the context of these Moxa devices, the firmware versions prior to 1.4 utilize weak entropy sources that result in predictable key generation patterns, making it feasible for attackers to compute or guess cryptographic keys used for secure communications.
The operational impact of this vulnerability is substantial for organizations relying on these industrial gateways for remote access and network management. Remote attackers who can obtain knowledge of cryptographic keys from one installation can potentially leverage this information to compromise other devices within the same product line. This creates a cascading security risk where a single compromised device can serve as a foothold for attacking multiple systems. The vulnerability specifically affects the authentication and encryption mechanisms that protect sensitive network communications, potentially allowing unauthorized access to device management interfaces, data exfiltration, and potential disruption of critical network operations.
This vulnerability aligns with CWE-330, which addresses insufficient entropy in cryptographic systems, and represents a significant weakness in the cryptographic implementation that violates fundamental security principles. The attack vector described in the CVE corresponds to techniques outlined in the MITRE ATT&CK framework under T1566 for credential access and T1071 for application layer protocols, as attackers can exploit predictable cryptographic keys to establish unauthorized access. Organizations should immediately update affected devices to firmware version 1.4 or later, which addresses the entropy source issues. Additional mitigations include implementing network segmentation, monitoring for unauthorized access attempts, and considering alternative authentication mechanisms. The vulnerability highlights the critical importance of proper cryptographic implementation in industrial control systems and demonstrates how seemingly minor implementation flaws can create significant security risks in critical infrastructure environments.