CVE-2018-4838 in EN100 Ethernet Module
Summary
by MITRE
A vulnerability has been identified in Siemens 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 web interface (TCP/80) of affected devices allows an unauthenticated user to upgrade or downgrade the firmware of the device, including to older versions with known vulnerabilities.
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Analysis
by VulDB Data Team • 02/17/2023
The vulnerability described in CVE-2018-4838 represents a critical security flaw in Siemens EN100 Ethernet modules across multiple communication protocols including IEC 61850, PROFINET IO, Modbus TCP, DNP3, and IEC 104. This issue affects a broad range of industrial automation devices that are commonly deployed in critical infrastructure environments such as power grids, water treatment facilities, and manufacturing plants. The vulnerability stems from improper access controls within the web interface of these devices, which operates on TCP port 80, making it accessible to any unauthenticated user on the network. This design flaw fundamentally compromises the device's integrity and security posture by allowing arbitrary firmware modification without proper authentication mechanisms.
The technical nature of this vulnerability aligns with CWE-284, which describes improper access control, and specifically relates to the lack of authentication requirements for critical system functions. An attacker exploiting this vulnerability can perform firmware upgrades or downgrades to any version of the device software, including older versions that contain known security vulnerabilities. This capability enables attackers to either install malicious firmware versions or downgrade to vulnerable releases that may contain previously patched exploits. The implications extend beyond simple privilege escalation since firmware modifications can fundamentally alter the device's operational behavior, potentially introducing backdoors, disabling security features, or creating new attack vectors. The vulnerability exists across all affected versions of the EN100 Ethernet modules, indicating a systemic design flaw rather than an isolated incident.
The operational impact of this vulnerability is severe for industrial control systems environments where these devices are deployed. Attackers can leverage this vulnerability to gain persistent access to industrial networks by installing backdoor firmware versions or exploiting known vulnerabilities in older firmware releases. This capability enables sophisticated attack campaigns that can remain undetected for extended periods while allowing attackers to manipulate industrial processes or create denial-of-service conditions. The vulnerability's exploitation does not require any specialized knowledge or credentials, making it particularly dangerous as it can be exploited by threat actors with minimal technical expertise. The affected devices are commonly used in critical infrastructure sectors where maintaining system integrity and availability is paramount, making this vulnerability a significant concern for industrial cybersecurity.
Mitigation strategies for CVE-2018-4838 should focus on network segmentation and access control measures to prevent unauthorized access to the affected devices. Organizations should implement strict firewall rules to block external access to TCP port 80 on these devices and ensure that only authorized personnel can access the web interface through secure channels. The most effective long-term solution involves applying firmware updates from Siemens that address this vulnerability by implementing proper authentication mechanisms for firmware upgrade functions. Network monitoring should be enhanced to detect unusual firmware modification activities, and regular security assessments should be conducted to identify any unauthorized changes to device configurations. Additionally, implementing network access control lists and disabling unnecessary services can significantly reduce the attack surface. The vulnerability's classification under the ATT&CK framework would include techniques such as T1072 Software Deployment Tools and T1566 Phishing for Information, as attackers may use compromised devices to establish persistence and conduct reconnaissance activities. Organizations should also consider implementing industrial network security solutions that provide real-time monitoring and anomaly detection capabilities to identify potential exploitation attempts.