Mitsubishi Melsex FX-series Programmable controllers

FX line controllers are used for automation of building engineering systems, in woodworking, printing houses, food and light industry, water industry, shipping and other areas. PLC - programmable logic controller is a microprocessor device designed for collecting, converting, processing, storing information and generating control commands, having a final number of inputs and outputs connected to them by sensors, switches, actuators to the control object, and designed for operation in real time modes.

Conditionally, all controllers can be divided into four groups:

• Small controllers or what microcontrollers also call them. These include Alpha Series Controllers (ALPHA). Used for small tasks that require maximum simplicity and reliability.
• Compact FX family controllers that combine power and simplicity. Ideal choice for small automation tasks in almost any industry.
• Mitsubishi Modular Programmable Logic Controllers (PLC SystemQ) are multifunctional, high-level controllers. It is a platform for a wide range of automation solutions, from autonomous management to networked and redundant systems. Tasks of any complexity level can be solved using these controllers.
• Mitsubishi Electric MELSEC ST Remote I/O Stations are a modular type remote I/O controller for connection to the Profibus network. "ST" means "Slicetype Terminal," i.e. a decentralized I/O system consisting of plug-in electronic modules.

2022: Detection of vulnerabilities associated with the risk of accessing confidential information in the PLC

Multiple vulnerabilities have been identified in Mitsubishi controllers. This was announced on April 21, 2022 by Positive Technologies.

Mitsubishi recommends using enciphering and. firewalls This will help minimize the risk of exploiting the vulnerabilities found.

Mitsubishi's industrial automation division has been on the Russian market for more than 20 years.

Problems were found in the all-in-one compact FX5U MELSEC series controllers iQ-F from the MELSEX FX line. Vulnerabilities were discovered by Positive Technologies experts Anton Dorfman, Ilya Rogachev, Dmitry Sklyarov and Arthur Akhatov. Two of them have a high level of risk.

Some vulnerabilities are associated with the risk of accessing confidential information in the PLC. For example, the attacker can find out the value of the password hash by intercepting traffic or using local access to certain files. Having a password hash and exploiting detected vulnerabilities, an attacker can bypass built-in security mechanisms, login to the PLC, and, for example, use the controller stop command or access protected files. Any such scenario can negatively affect production, "said Vladimir Nazarov, head of the safety department of industrial control systems at Positive Technologies.

And this is the risk of compromising the APCS network and a threat to the planned work of the enterprise, "said Vladimir Nazarov.

To exploit detected vulnerabilities, it is enough for an attacker to have network access to the controller or, in the case of network segmentation, to be on a local network with a PLC. The degree of hazard of identified vulnerabilities varies from 5.9 to 7.4 on the CVSS v3.1 scale: CVE-2022-25155 (5.9), CVE-2022-25156 (5.9), CVE-2022-25159 (5.9), CVE-2022-25160 (6.8), CVE-7.4-2022-158,

All models and versions are exposed to threats:

• FX5U (C) processor module
• FX5UJ CPU module.