CVE-2019-5156 in PFC200
Summary
by MITRE
An exploitable command injection vulnerability exists in the cloud connectivity functionality of WAGO PFC200 versions 03.02.02(14), 03.01.07(13), and 03.00.39(12). An attacker can inject operating system commands into the TimeoutPrepared parameter value contained in the firmware update command.
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Analysis
by VulDB Data Team • 04/13/2024
The vulnerability identified as CVE-2019-5156 represents a critical command injection flaw within the WAGO PFC200 industrial automation devices, specifically affecting firmware versions 03.02.02(14), 03.01.07(13), and 03.00.39(12). This issue resides within the cloud connectivity functionality of these programmable logic controllers, which are widely deployed in industrial environments for process control and automation. The affected devices are manufactured by WAGO, a leading provider of industrial automation and control systems that serve various sectors including manufacturing, energy, and infrastructure management. The vulnerability stems from insufficient input validation and sanitization within the firmware update command processing mechanism, creating a pathway for malicious actors to execute arbitrary operating system commands on the affected devices. This flaw is particularly concerning given the industrial control systems environment where these devices operate, as it could potentially compromise critical infrastructure operations.
The technical implementation of this vulnerability occurs through the TimeoutPrepared parameter within the firmware update command structure. When an attacker crafts a malicious payload containing operating system commands within this parameter value, the system fails to properly validate or sanitize the input before processing. This allows the injected commands to be executed with the privileges of the firmware update process, typically running with elevated system permissions. The vulnerability manifests as a classic command injection attack vector where user-supplied input directly influences the execution of system commands without proper sanitization. According to CWE standards, this maps to CWE-77 and CWE-88, which classify the issue as command injection through improper input validation. The attack requires an authenticated session to interact with the firmware update functionality, making it less accessible than fully remote exploits but still highly dangerous in environments where physical or network access is possible.
The operational impact of CVE-2019-5156 extends beyond simple privilege escalation to potentially enable complete system compromise and disruption of industrial processes. An attacker who successfully exploits this vulnerability could gain full control over the affected PFC200 device, allowing them to modify firmware, access sensitive operational data, or even cause physical damage to industrial processes. The implications are particularly severe in critical infrastructure environments where these controllers manage processes such as chemical plant operations, power generation, or water treatment facilities. The vulnerability could enable attackers to manipulate control systems, potentially leading to safety hazards, production disruptions, or environmental damage. From an attack perspective, this aligns with ATT&CK techniques involving command and control through system binaries and privilege escalation, as the attacker leverages the legitimate firmware update functionality to execute malicious commands. The affected industrial environments often lack traditional cybersecurity controls, making such vulnerabilities more dangerous as they may not be detected by standard network monitoring systems.
Mitigation strategies for CVE-2019-5156 must address both immediate remediation and long-term security improvements. The primary recommendation involves applying the official firmware updates provided by WAGO to patch the vulnerability, which should be prioritized in all affected environments. Network segmentation and access control measures should be implemented to limit who can interact with the firmware update functionality, reducing the attack surface. Additionally, implementing input validation controls and sanitization mechanisms within the firmware update process can help prevent similar issues in the future. Organizations should conduct comprehensive vulnerability assessments of their industrial control systems to identify other potential command injection vulnerabilities. Security monitoring should include detection of unusual firmware update activities and command execution patterns. The vulnerability highlights the need for robust security practices in industrial environments, including regular security assessments, secure configuration management, and incident response procedures specifically tailored for industrial control systems. Given the critical nature of these systems, organizations should also consider implementing zero-trust network architectures and continuous monitoring solutions designed for industrial environments to detect and respond to such threats effectively.