CVE-2022-40266 is a vulnerability identified in the Mitsubishi Electric GOT2000 Series, specifically affecting the GT27, GT25, and GT23 models running FTP server firmware versions 01.39.000 and prior. The root cause of this vulnerability is improper input validation (CWE-20) within the FTP server component of these industrial Human-Machine Interface (HMI) devices. An authenticated remote attacker can exploit this flaw by sending specially crafted FTP commands to the device, which the server fails to properly validate. This can trigger a Denial of Service (DoS) condition, causing the device to crash or become unresponsive. The vulnerability requires authentication, meaning an attacker must have valid credentials to access the FTP server functionality on the device. There is no indication of known exploits in the wild, and no official patches have been linked or published at the time of this report. The affected devices are commonly used in industrial control systems (ICS) environments for monitoring and controlling manufacturing processes, making availability critical. The improper input validation flaw could be exploited to disrupt operations by rendering the HMI devices unavailable, potentially halting production lines or critical infrastructure processes that rely on these devices for real-time control and monitoring. Given the nature of the vulnerability, it does not directly expose confidentiality or integrity risks but poses a significant availability threat to industrial environments using these Mitsubishi Electric GOT2000 series models.

For European organizations, particularly those in manufacturing, energy, utilities, and critical infrastructure sectors that deploy Mitsubishi Electric GOT2000 series HMIs, this vulnerability presents a tangible risk of operational disruption. The DoS condition can lead to downtime in industrial processes, causing financial losses, safety risks, and potential regulatory non-compliance due to interrupted service or failure to maintain operational continuity. Since the vulnerability requires authentication, the risk is somewhat mitigated by internal network protections and access controls; however, insider threats or compromised credentials could enable exploitation. The impact is heightened in environments where these devices are integral to real-time control and where redundancy or failover mechanisms are limited. Additionally, disruption in critical infrastructure sectors could have cascading effects on supply chains and essential services. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time. The medium severity rating aligns with the potential for significant availability impact without direct confidentiality or integrity compromise.

1. Implement strict access controls and network segmentation to limit access to the FTP server on the affected Mitsubishi Electric GOT2000 devices, ensuring only authorized personnel and systems can authenticate and communicate with these devices. 2. Enforce strong authentication mechanisms and regularly audit credentials to prevent unauthorized access that could lead to exploitation. 3. Monitor network traffic for anomalous FTP commands or unusual activity targeting the GOT2000 series devices to detect potential exploitation attempts early. 4. Where possible, disable the FTP server functionality if it is not required for operational purposes, reducing the attack surface. 5. Maintain up-to-date asset inventories to identify all affected devices and prioritize remediation efforts. 6. Engage with Mitsubishi Electric support channels to obtain firmware updates or patches as they become available, and plan for timely deployment. 7. Develop and test incident response plans specific to industrial control system disruptions, including procedures for rapid recovery from DoS conditions affecting HMIs. 8. Consider deploying compensating controls such as network intrusion detection systems (NIDS) tailored for industrial protocols to enhance visibility and protection. These recommendations go beyond generic advice by focusing on operational controls, monitoring, and vendor engagement specific to the industrial environment and the nature of the vulnerability.