The increasing adoption of the Industrial Internet of Things (IIoT) has led to significant improvements in operational efficiency but has also brought new challenges for cybersecurity. To address these challenges, a number of standards have been introduced over the years. One of the best-known series of standards for this purpose is ISA/IEC 62443. This paper examines the applicability of the ISA/IEC 62443 series of standards, traditionally used for securing industrial automation and control systems, to the IIoT environment. For each requirement described in the ISA/IEC 62443 standards, relevant research on that subject is reviewed and presented in a table-like manner. Based on this table, areas for future research are identified, including system hardening, asset inventory, safety instrumented system isolation, risk assessment methodologies, change management systems, data storage security, and incident response procedures. The focus on future improvement is performed for the area of system hardening, for which research and guidelines already exist but not for the specific area of IIoT environments.

Increasing interdependencies between critical infrastructures and digitization increase the vulnerability to cyber-attacks and cyber-physical attacks. Incidents have multiple direct and indirect consequences, including cascading effects, and a formal analysis is strongly recommended to understand these effects. This paper shows how threat identification and impact evaluation for interdependent critical infrastructures can be supported by two existing tools. The approach is illustrated with an example based on a running EU project.