This part of IEC 62443 provides a current assessment of various cybersecurity tools, mitigation counter-measures, and technologies that may effectively apply to the modern electronically based IACSs regulating and monitoring numerous industries and critical infrastructures. It describes several categories of control system-centric cybersecurity technologies, the types of products available in those categories, the pros and cons of using those products in the automated IACS environments, relative to the expected threats and known cyber vulnerabilities, and, most important, the preliminary recommendations and guidance for using these cybersecurity technology products and/or countermeasures. The concept of IACS cybersecurity as applied in this technical report is in the broadest possible sense, encompassing all types of components, plants, facilities, and systems in all industries and critical infrastructures. IACSs include, but are not limited to: • Hardware (e.g., data historian servers) and software systems (e.g., operating platforms, configurations, applications) such as Distributed Control Systems (DCSs), Programmable Logic Controllers (PLCs), Supervisory Control and Data Acquisition (SCADA) systems, networked electronic sensing systems, and monitoring, diagnostic, and assessment systems. Inclusive in this hardware and software domain is the essential industrial network and any connected or related information technology (IT) devices and links critical to the successful operation to the control system at large. As such, this domain also includes, but is not limited to: firewalls, servers, routers, switches, gateways, fieldbus systems, intrusion detection systems, intelligent electronic/end devices, remote terminal units (RTUs), and both wired and wireless remote modems. • Associated internal, human, network, or machine interfaces used to provide control, data logging, diagnostics, safety, monitoring, maintenance, quality assurance, regulatory compliance, auditing and other types of operational functionality for either continuous, batch, discrete, and combined processes.