CVE-2020-9435 in TC ROUTER 3002T-4G
Summary
by MITRE
PHOENIX CONTACT TC ROUTER 3002T-4G through 2.05.3, TC ROUTER 2002T-3G through 2.05.3, TC ROUTER 3002T-4G VZW through 2.05.3, TC ROUTER 3002T-4G ATT through 2.05.3, TC CLOUD CLIENT 1002-4G through 2.03.17, and TC CLOUD CLIENT 1002-TXTX through 1.03.17 devices contain a hardcoded certificate (and key) that is used by default for web-based services on the device. Impersonation, man-in-the-middle, or passive decryption attacks are possible if the generic certificate is not replaced by a device-specific certificate during installation.
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Analysis
by VulDB Data Team • 04/16/2024
The vulnerability identified as CVE-2020-9435 affects a range of PHOENIX CONTACT networking devices including various TC ROUTER and TC CLOUD CLIENT models. This security flaw stems from the inclusion of a hardcoded certificate and corresponding private key within the device firmware, which serves as the default authentication mechanism for web-based services. The presence of such a universal credential creates a fundamental weakness in the device's security architecture, as it eliminates the possibility of device-specific cryptographic identity and establishes a single point of failure across all affected units. This hardcoded certificate is designed to be used by default without requiring administrators to configure custom credentials during deployment, which inadvertently creates a widespread security risk. The vulnerability resides in the device's firmware implementation where cryptographic materials are embedded in the software rather than being generated dynamically or provisioned uniquely for each device instance.
The technical exploitation of this vulnerability allows threat actors to perform several types of attacks that directly compromise the integrity and confidentiality of communications between the affected devices and their management interfaces. An attacker who gains access to the network can leverage the hardcoded certificate to impersonate legitimate devices, effectively bypassing authentication mechanisms that should protect the web-based management services. This capability enables man-in-the-middle attacks where the attacker can intercept, modify, or redirect traffic between the device and its administrators. Additionally, the presence of the corresponding private key allows for passive decryption of communications, enabling eavesdropping on sensitive data exchanges that should remain confidential. The attack surface extends to any device that relies on the default web services for management, configuration, or monitoring functions, making the impact particularly severe given the widespread deployment of these networking devices in industrial and commercial environments.
The operational impact of this vulnerability is significant for organizations that deploy PHOENIX CONTACT devices in critical infrastructure or industrial control systems. The hardcoded certificate creates a persistent risk that affects all affected devices regardless of their location or configuration state, as the default credentials remain active even when administrators attempt to change other settings. This vulnerability directly violates security best practices outlined in industry standards such as the NIST Cybersecurity Framework and ISO/IEC 27001, which emphasize the importance of unique cryptographic identities and proper key management. The vulnerability also aligns with CWE-312 (Sensitive Data in Memory) and CWE-311 (Missing Encryption of Sensitive Data) categories, as it exposes cryptographic materials that should remain protected and unique to individual devices. Organizations may face compliance challenges with regulatory frameworks such as the EU's NIS Directive and various industrial security standards that require robust authentication and encryption mechanisms.
Mitigation strategies for this vulnerability require immediate action from device administrators and security teams. The primary recommendation involves replacing the hardcoded certificate with device-specific certificates generated through a trusted certificate authority, which addresses the fundamental issue of shared credentials across multiple devices. Organizations should implement certificate management procedures that ensure each device receives unique cryptographic identities during deployment and establish regular certificate rotation schedules. Network segmentation and access control measures should be implemented to limit exposure of the affected web services to unauthorized users. The vulnerability also highlights the importance of firmware update management, as PHOENIX CONTACT has likely released patches to address this issue, and organizations should ensure all devices are running the latest secure firmware versions. Security monitoring should be enhanced to detect unusual access patterns or attempts to leverage the hardcoded credentials, while incident response procedures should be updated to include specific actions for addressing hardcoded certificate vulnerabilities. This remediation approach aligns with the MITRE ATT&CK framework's defense evasion and credential access tactics, requiring proactive security measures to prevent exploitation of the hardcoded cryptographic materials.