CVE-2016-4784 in EN100 Ethernet Module
Summary
by MITRE
The integrated web server in the EN100 Ethernet module before 4.27 on Siemens SIPROTEC 4 and SIPROTEC Compact devices, and the Ethernet Service Interface on SIPROTEC Compact devices, allows remote attackers to obtain sensitive information via an HTTP request.
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Analysis
by VulDB Data Team • 08/22/2022
The vulnerability identified as CVE-2016-4784 represents a critical information disclosure flaw within Siemens SIPROTEC 4 and SIPROTEC Compact protective relaying devices. These industrial control systems are widely deployed in critical infrastructure environments including power generation, transmission, and distribution facilities where they serve as essential components for electrical protection and monitoring. The affected devices operate with integrated web servers that provide remote access capabilities for configuration and monitoring purposes, but this functionality contains a significant security weakness that exposes sensitive operational data to unauthorized remote access.
The technical flaw stems from improper access control mechanisms within the integrated web server implementation. When remote attackers send specially crafted HTTP requests to the affected devices, they can bypass authentication requirements and gain access to sensitive operational information that should remain restricted to authorized personnel only. This vulnerability specifically affects devices running firmware versions prior to 4.27 and impacts both the EN100 Ethernet module and the Ethernet Service Interface components. The flaw essentially allows attackers to retrieve configuration data, system parameters, operational logs, and other confidential information that could reveal critical details about the industrial control system architecture and operational procedures.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates significant risks for industrial control system security. Attackers who exploit this vulnerability can gather detailed information about the target network topology, device configurations, and operational parameters that could be used to plan more sophisticated attacks. This information disclosure could enable adversaries to identify potential attack vectors, understand system dependencies, and develop targeted strategies for disrupting critical infrastructure operations. The vulnerability particularly affects environments where these devices are deployed in power grid systems, where such information could be leveraged to compromise grid stability and security. According to CWE classification, this vulnerability maps to CWE-200 - Information Exposure, specifically involving insufficient access control mechanisms that allow unauthorized information disclosure.
The threat landscape surrounding this vulnerability is particularly concerning given the critical nature of the affected systems. Industrial control systems like SIPROTEC devices are often deployed in environments where security is paramount, yet they frequently lack robust security controls due to their specialized nature and the historical focus on operational reliability over cybersecurity. The remote exploitation capability means that attackers can potentially compromise these systems from anywhere on the internet without requiring physical access or specialized equipment. This vulnerability aligns with ATT&CK technique T1082 - System Information Discovery, where adversaries gather information about the target system to inform further attack phases. Organizations using these devices face significant risk of operational disruption, data compromise, and potential safety hazards if attackers exploit this vulnerability to understand system behavior and plan targeted attacks.
Mitigation strategies for CVE-2016-4784 should prioritize immediate firmware updates to version 4.27 or later, which contain the necessary security patches to address the access control weakness. Network segmentation and access control measures should be implemented to limit direct internet access to these devices, while also deploying firewalls and intrusion detection systems to monitor for suspicious HTTP traffic patterns. Organizations should conduct comprehensive vulnerability assessments to identify all affected devices within their industrial control system environments and establish monitoring procedures for detecting unauthorized access attempts. Additionally, implementing network access controls, disabling unnecessary web server functionality, and establishing secure remote access protocols through VPN connections can help reduce the attack surface and prevent exploitation of this vulnerability.