CVE-2019-5160 in PFC200
Summary
by MITRE
An exploitable improper host validation vulnerability exists in the Cloud Connectivity functionality of WAGO PFC200 Firmware versions 03.02.02(14), 03.01.07(13), and 03.00.39(12). A specially crafted HTTPS POST request can cause the software to connect to an unauthorized host, resulting in unauthorized access to firmware update functionality. An attacker can send an authenticated HTTPS POST request to direct the Cloud Connectivity software to connect to an attacker controlled Azure IoT Hub node.
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Analysis
by VulDB Data Team • 04/13/2024
The vulnerability described in CVE-2019-5160 represents a critical improper host validation flaw within the Cloud Connectivity functionality of WAGO PFC200 industrial control devices. This issue stems from insufficient validation of hostnames and endpoints during firmware update operations, creating a pathway for malicious actors to redirect legitimate communication channels to unauthorized servers. The vulnerability specifically affects firmware versions 03.02.02(14), 03.01.07(13), and 03.00.39(12) where the software fails to properly authenticate or validate the destination of HTTPS POST requests destined for cloud connectivity services. The flaw allows attackers to manipulate the device's cloud communication behavior by crafting specially crafted HTTPS POST requests that redirect the device's firmware update functionality to attacker-controlled infrastructure.
The technical exploitation of this vulnerability leverages the trust relationship between the industrial device and its intended cloud services, specifically targeting the Azure IoT Hub integration. When an authenticated HTTPS POST request is sent to the device, the improper validation allows the attacker to specify an alternative hostname or endpoint that the device will connect to for firmware updates. This misconfiguration creates an attack surface where legitimate firmware update operations can be hijacked to deliver malicious payloads or establish unauthorized communication channels. The vulnerability falls under CWE-295 which specifically addresses improper certificate validation and host name verification in secure communications. The attack vector demonstrates how weak input validation in network communication protocols can lead to significant security implications in industrial control systems.
The operational impact of CVE-2019-5160 extends beyond simple unauthorized access, creating potential for complete system compromise and operational disruption in industrial environments. Attackers can leverage this vulnerability to perform man-in-the-middle attacks, intercept firmware update processes, or deliver malicious firmware to the targeted devices. The implications are particularly severe in industrial control systems where firmware integrity is critical for operational safety and security. The ability to redirect cloud connectivity to attacker-controlled infrastructure means that legitimate firmware updates can be replaced with malicious versions, potentially leading to system instability, data corruption, or complete system compromise. This vulnerability directly impacts the integrity of the industrial control ecosystem and can undermine the security posture of entire industrial networks.
Mitigation strategies for CVE-2019-5160 should focus on implementing proper host validation mechanisms and strengthening the authentication processes for cloud connectivity features. Organizations should apply firmware updates from WAGO that address the improper host validation issue, ensuring that all cloud communication endpoints are properly validated before establishing connections. Network segmentation and firewall rules should be implemented to restrict outbound connections from industrial devices to only authorized cloud services, preventing unauthorized redirection attempts. Additionally, monitoring and logging of cloud connectivity activities should be enhanced to detect suspicious connection patterns or attempts to redirect device communication to unauthorized endpoints. The vulnerability highlights the importance of secure communication protocols and proper input validation in industrial control systems, aligning with ATT&CK technique T1071.004 for application layer protocol: DNS to ensure that all network communications are properly authenticated and validated against known good endpoints.