CVE-2025-7405 is a high-severity vulnerability affecting Mitsubishi Electric Corporation's MELSEC iQ-F Series FX5U-32MT/ES CPU modules, specifically versions 1.060 and later. The vulnerability arises from the lack of authentication mechanisms in the MODBUS/TCP protocol implementation on these devices. MODBUS/TCP is a widely used industrial communication protocol for supervisory control and data acquisition (SCADA) systems and programmable logic controllers (PLCs). In this case, the absence of authentication allows a remote attacker to connect to the device without credentials and perform unauthorized read and write operations on device values. This includes the ability to stop the execution of running programs on the PLC, effectively disrupting industrial processes controlled by these devices. The vulnerability is classified under CWE-306 (Missing Authentication for Critical Function), indicating that critical functions are exposed without proper access control. The CVSS 3.1 base score is 7.3, reflecting a high severity with network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and impacts on confidentiality, integrity, and availability (C:L/I:L/A:L). Although no known exploits are currently reported in the wild, the ease of exploitation and critical nature of the affected functions make this a significant threat to industrial environments relying on these PLCs. The lack of authentication means that any attacker with network access to the MODBUS/TCP interface can manipulate device states, potentially causing operational downtime, safety hazards, or data integrity issues in industrial control systems.

For European organizations, especially those in manufacturing, energy, utilities, and critical infrastructure sectors that utilize Mitsubishi MELSEC iQ-F Series PLCs, this vulnerability poses a serious risk. Exploitation could lead to unauthorized control over industrial processes, resulting in production halts, equipment damage, or safety incidents. The ability to stop program execution remotely can disrupt supply chains and operational continuity. Confidentiality impacts, while lower, could expose sensitive operational data or system configurations. Given Europe's strong industrial base and reliance on automation, the vulnerability could affect a wide range of sectors including automotive manufacturing, chemical plants, water treatment facilities, and power generation. Additionally, the interconnected nature of industrial networks and increasing adoption of Industry 4.0 technologies amplify the risk of lateral movement and broader network compromise following exploitation. The absence of authentication also raises concerns about insider threats or compromised internal networks being leveraged to attack these devices. Overall, the vulnerability threatens operational integrity and availability, which are critical for maintaining safety and regulatory compliance in European industrial environments.

To mitigate this vulnerability, European organizations should implement the following specific measures: 1) Network Segmentation: Isolate PLCs and other industrial control devices on dedicated, secured network segments with strict access controls to limit exposure of MODBUS/TCP interfaces to untrusted networks. 2) Access Control Lists (ACLs): Configure firewalls and network devices to restrict MODBUS/TCP traffic only to authorized management stations and control systems. 3) Use of VPNs or Secure Tunnels: Where remote access is necessary, enforce encrypted tunnels with strong authentication to protect communications to PLCs. 4) Monitoring and Anomaly Detection: Deploy industrial intrusion detection systems (IDS) capable of recognizing unauthorized MODBUS commands or unusual traffic patterns indicative of exploitation attempts. 5) Vendor Coordination: Engage with Mitsubishi Electric for firmware updates or patches addressing authentication mechanisms; if unavailable, request guidance or compensating controls. 6) Application Whitelisting and Program Integrity Checks: Implement mechanisms to verify PLC program integrity and detect unauthorized modifications. 7) Incident Response Preparedness: Develop and test response plans specific to industrial control system compromises, including rapid isolation of affected devices. 8) Physical Security: Ensure physical access to PLCs is restricted to prevent direct tampering. These targeted steps go beyond generic advice by focusing on network architecture, monitoring, and vendor engagement tailored to the industrial environment and this specific vulnerability.