CVE-2017-5159 in mGuard
Summary
by MITRE
An issue was discovered on Phoenix Contact mGuard devices that have been updated to Version 8.4.0. When updating an mGuard device to Version 8.4.0 via the update-upload facility, the update will succeed, but it will reset the password of the admin user to its default value.
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Analysis
by VulDB Data Team • 12/18/2020
The vulnerability identified as CVE-2017-5159 affects Phoenix Contact mGuard devices running Version 8.4.0, representing a critical security flaw in the device's firmware update mechanism. This issue manifests during the update process when administrators attempt to upgrade their mGuard devices through the designated update-upload facility. The flaw constitutes a privilege escalation vulnerability that undermines the device's authentication security model and creates a persistent backdoor access vector for unauthorized parties.
The technical implementation of this vulnerability lies within the firmware update procedure itself, where the system fails to maintain existing administrative credentials during the update process. Specifically, when a device receives an update through the upload mechanism, the system automatically resets the admin user account to its default password state, effectively nullifying any custom authentication configurations that may have been implemented by the device administrator. This behavior represents a violation of the principle of least privilege and demonstrates a critical failure in the device's security configuration management during firmware transitions.
The operational impact of this vulnerability is severe and far-reaching, as it provides unauthorized actors with persistent administrative access to the affected devices. Once an attacker successfully uploads a firmware update to a vulnerable mGuard device, they gain immediate administrative control without requiring knowledge of the original password. This creates a significant risk for industrial control systems and network security infrastructure, as the mGuard devices typically serve as security gateways and network monitoring appliances. The vulnerability essentially allows for a complete compromise of the device's security posture, potentially enabling attackers to manipulate network traffic, disable security features, or establish persistent access points within the network environment.
This vulnerability aligns with CWE-284, which addresses improper access control in software systems, and represents a failure in authentication management during critical system operations. From an ATT&CK framework perspective, this issue maps to privilege escalation techniques and can be leveraged to establish persistence within network environments. The vulnerability also demonstrates poor secure coding practices in firmware development, specifically regarding the handling of authentication credentials during system updates and the lack of proper validation of update processes.
Organizations should immediately implement mitigations including immediate firmware updates to versions that address this vulnerability, network segmentation to limit access to affected devices, and enhanced monitoring of update activities. Additionally, administrators should verify that all mGuard devices are running patched firmware versions and should consider implementing additional authentication controls such as multi-factor authentication where possible. The vulnerability highlights the critical importance of secure firmware update mechanisms and proper credential management during system maintenance operations, emphasizing that update processes must never compromise existing security configurations.