ICS Purdue Model in Industrial Internet of Things (IIoT) & Cloud

OT Cybersecurity teams have been working within the Purdue Enterprise Reference Architecture since it was created in the mid-1990s. Although not developed as a security model, by mapping the interconnections and interdependencies of the high-level components of typical industrial control systems (ICS), the Purdue reference architecture has provided important guidance for how to defend OT systems. The adoption of numerous IT systems into OT environments, however, has raised questions about the continued relevance of the ICS Purdue model.

The adoption of numerous IT systems into OT environments, however, has raised questions about the continued relevance of the Purdue model.

The Purdue Enterprise Reference Architecture

By way of a quick review, the current Purdue architecture models OT and IT into six functional levels that run from Level 0 to Level 5 and span three zones.

• Level 0 — Physical process: This is the physical equipment that actually does the work and is known as the equipment under control. This consists of valves, pumps, sensors, actuators, compressors, etc.

• Level 1 — Basic Control: These are the control devices such as programmable logic controllers that monitor and control Level 0 equipment and safety instrumented systems.

• Level 2 — Area Supervisory Control: Control logic for analyzing and acting on Level 1 data. Systems include human-machine interface (HMI); supervisory and data acquisition (SCADA) software.

• Level 3 — Site Control: This level includes systems that support plant-wide control and monitoring functions. Level 3 systems also aggregate lower level data that needs to be pushed up to higher-level business systems.

• Level 4 — IT Systems: Business logistics systems can include database servers, application servers, and file servers.

• Level 5 — Corporate Network: A broader set of enterprise IT systems, including connections to the public Internet.

These levels are typically described as creating three logical zones, with Levels (Read more...)