CVE-2018-7847 in Modicon M580
Summary
by MITRE
A CWE-284: Improper Access Control vulnerability exists in all versions of the Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium which could cause denial of service or potential code execution by overwriting configuration settings of the controller over Modbus.
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Analysis
by VulDB Data Team • 09/23/2023
The vulnerability identified as CVE-2018-7847 represents a critical improper access control flaw classified under CWE-284 that affects several legacy industrial automation controllers including the Modicon M580, M340, Quantum, and Premium series. This weakness stems from insufficient authentication and authorization mechanisms within the Modbus communication protocol implementation, allowing unauthenticated attackers to exploit the system's configuration interfaces. The vulnerability specifically targets the controller's configuration settings, which are typically protected through secure access controls but fail to properly validate incoming requests. Attackers can leverage this flaw to perform unauthorized modifications to critical system parameters, potentially leading to complete system compromise or operational disruption.
The technical exploitation of this vulnerability occurs through the Modbus protocol which is widely used in industrial control systems for communication between devices and controllers. When an attacker successfully connects to the affected controllers via Modbus, they can send specially crafted requests that bypass normal access controls and overwrite configuration parameters. This manipulation can occur without requiring valid credentials or authentication, making the attack surface particularly dangerous in environments where physical or network access is not properly restricted. The flaw essentially allows an attacker to inject malicious configuration data that can alter how the controller operates, potentially leading to denial of service conditions or even code execution capabilities that could enable further exploitation.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass potential system compromise and operational disruption in critical infrastructure environments. Industrial control systems that rely on these Modicon controllers for process automation, manufacturing control, or power grid management face significant risk when this vulnerability exists in their network. A successful exploitation could result in production halts, safety system failures, or unauthorized modification of process parameters that could lead to hazardous conditions. The vulnerability is particularly concerning because these controllers are often deployed in environments where physical security is limited, and network segmentation may not be properly implemented. The attack vector through Modbus makes it accessible to anyone who can establish network connectivity to the affected devices, potentially allowing remote exploitation from outside the facility's network perimeter.
Mitigation strategies for CVE-2018-7847 should focus on implementing robust network segmentation and access controls to prevent unauthorized access to industrial control systems. Organizations should enforce strict network isolation of critical controllers using firewalls, network access control systems, and proper VLAN configurations to limit Modbus communication to authorized systems only. The implementation of secure remote access solutions with strong authentication mechanisms becomes critical when remote access is required for maintenance or monitoring purposes. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar access control weaknesses in industrial control systems. Additionally, implementing network monitoring solutions that can detect anomalous Modbus traffic patterns and unauthorized configuration changes can provide early warning of potential exploitation attempts. System administrators should also consider implementing controller firmware updates where available and establishing strict change management procedures for configuration modifications to ensure that any alterations to critical parameters are properly authorized and documented. This vulnerability highlights the importance of following industrial security standards such as those defined in the NIST Cybersecurity Framework and IEC 62443 for protecting critical infrastructure from unauthorized access and manipulation.