CVE-2018-4840 in EN100 Ethernet Module
Summary
by MITRE
A vulnerability has been identified in Siemens DIGSI 4 (All versions < V4.92), EN100 Ethernet module IEC 61850 variant (All versions < V4.30), EN100 Ethernet module PROFINET IO variant (All versions), EN100 Ethernet module Modbus TCP variant (All versions), EN100 Ethernet module DNP3 variant (All versions), EN100 Ethernet module IEC 104 variant (All versions). The device engineering mechanism allows an unauthenticated remote user to upload a modified device configuration overwriting access authorization passwords.
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Analysis
by VulDB Data Team • 02/17/2023
This vulnerability exists within Siemens DIGSI 4 software and multiple EN100 Ethernet module variants that support various industrial communication protocols including IEC 61850, PROFINET IO, Modbus TCP, DNP3, and IEC 104. The flaw resides in the device engineering mechanism which fails to properly authenticate remote access attempts, allowing any unauthenticated user to establish a connection and upload modified device configuration files. This represents a critical security weakness that directly violates fundamental principles of access control and authentication as defined in CWE-287, which addresses improper authentication issues. The vulnerability affects all versions of the software prior to V4.92 for DIGSI 4 and specific versions for the EN100 Ethernet modules, indicating a widespread exposure across industrial control systems that rely on these communication protocols.
The technical implementation of this vulnerability stems from insufficient input validation and authentication mechanisms within the configuration upload process. When an unauthenticated remote user connects to the device, the system does not properly verify the identity of the connecting entity before accepting configuration modifications. This allows an attacker to overwrite access authorization passwords and potentially gain unauthorized administrative control over the industrial device. The attack vector is particularly concerning as it requires no prior authentication credentials, making it accessible to any remote user who can reach the device through network communication. This aligns with ATT&CK technique T1078 which covers valid accounts and T1566 which addresses credential harvesting and phishing attacks, though in this case the vulnerability creates a path for unauthorized access without requiring stolen credentials.
The operational impact of this vulnerability extends beyond simple password modification, as it fundamentally compromises the security posture of industrial control systems. An attacker who successfully exploits this vulnerability can gain persistent access to critical infrastructure devices, potentially leading to unauthorized configuration changes, data manipulation, or disruption of industrial processes. The affected EN100 Ethernet modules serve as communication gateways between industrial networks and external systems, making them prime targets for attackers seeking to establish footholds within industrial control networks. This vulnerability directly impacts the integrity and availability of industrial systems as described in the CIA triad, where unauthorized configuration changes can lead to system instability or complete operational failure. The implications are particularly severe in environments where these modules control critical infrastructure such as power grids, water treatment facilities, or manufacturing processes.
Organizations should immediately implement network segmentation to isolate affected devices from general network access, ensuring that only authorized personnel can reach these industrial control systems. Patch management procedures must be prioritized to upgrade all affected DIGSI 4 installations to version V4.92 or higher, and all EN100 Ethernet module variants to their respective patched versions. Network monitoring should be enhanced to detect unusual configuration upload activities, as this vulnerability can be exploited without generating typical authentication failure logs. The implementation of strong access controls including multi-factor authentication and network access control lists should be enforced to prevent unauthorized remote access. Additionally, regular security assessments should be conducted to identify and remediate similar authentication weaknesses in industrial control systems, following the principles outlined in NIST SP 800-82 and IEC 62443 standards for industrial network security.