1. What is the primary purpose of the Purdue Model in industrial control systems (ICS)?

• To maximize network speed
• To provide a framework for network segmentation and security
• To manage enterprise IT assets
• To standardize physical safety procedures

2. Which level of the Purdue Model contains the basic sensors, actuators, and other physical process devices?

• Level 0
• Level 1
• Level 2
• Level 3

3. Programmable Logic Controllers (PLCs) and Distributed Control Systems (DCS) typically reside at which level?

• Level 0
• Level 1
• Level 2
• Level 4

4. The boundary between the enterprise (IT) network and the industrial (OT) network is known as the:

• Production Line
• Safety Zone
• Industrial Demilitarized Zone (IDMZ)
• Control Loop

5. What is located in Level 4 of the Purdue Model?

• Human-Machine Interfaces (HMIs)
• Physical Process
• Enterprise IT Systems (e.g., ERP, email servers)
• Basic Control Devices

6. The concept of "segmentation" in the Purdue Model aims to:

• Combine all networks into one for easier management
• Isolate different functional areas to contain threats
• Ensure all devices can communicate with each other freely
• Increase the physical distance between devices

7. Which level is responsible for supervisory control, such as HMIs and SCADA software?

• Level 0
• Level 1
• Level 2
• Level 4

8. A key security principle of the Purdue Model is that communication should generally NOT bypass levels. This is known as:

• Open Access Policy
• No direct communication rule
• Network Bridging
• Flat Network Architecture

9. The Industrial Demilitarized Zone (IDMZ) is typically placed between which two levels?

• Level 0 and Level 1
• Level 1 and Level 2
• Level 2 and Level 3
• Level 3 and Level 4

10. What kind of systems would you find in Level 3, the Manufacturing Operations Management level?

• Email and web servers
• Batch management and data historians
• Motors and valves
• PLCs and RTUs

11. Why is direct communication between the Enterprise Zone (Level 4/5) and the Control Zone (Level 0-2) discouraged?

• It slows down the network
• It exposes critical control devices to threats from the internet and business network
• It is physically impossible to connect them
• It requires expensive cabling

12. Which of these is a common security control used within the IDMZ?

• A single, open router
• Firewalls, reverse proxies, and patch management servers
• Direct connections to all control devices
• Wireless access points with no password

13. The "air gap" concept, while often discussed, is difficult to maintain in modern ICS. The Purdue Model offers a more practical approach through:

• Complete network isolation
• Controlled and monitored communication conduits
• Using only analog devices
• Eliminating all network connections

14. What does "OT" stand for in the context of the Purdue Model?

• Over Time
• Official Technology
• Operational Technology
• Open Topology

15. A historian server, which collects and stores large amounts of process data, is typically found in:

• Level 1
• Level 5 (Enterprise)
• Level 3 or the IDMZ
• Level 0

16. Which level is considered the most critical in terms of safety and real-time control?

• Level 4
• Level 3
• Levels 0 and 1
• Level 5

17. A firewall rule allowing traffic from a Level 4 ERP system directly to a Level 1 PLC would be a violation of the Purdue Model's principles. True or False?

• True
• False

18. The "Safety Instrumented System" (SIS) operates independently but is often considered part of which level?

• Level 4
• Level 1
• Level 3
• Level 5

19. What is the main difference in priorities between IT and OT cybersecurity?

• There is no difference.
• IT prioritizes Confidentiality, while OT prioritizes Availability and Safety.
• OT prioritizes data privacy above all else.
• IT is not concerned with availability.

20. Level 5 in the Purdue Model represents the:

• Local Control Room
• Manufacturing Zone
• External Network / Internet
• Physical Process

21. An engineering workstation used to program PLCs would typically be found at:

• Level 4
• Level 2
• Level 0
• Level 5

22. Implementing the Purdue Model helps achieve "Defense in Depth". What does this mean?

• Having one very strong outer firewall.
• Relying solely on antivirus software.
• Layering multiple security controls, so if one fails, others are still in place.
• Encrypting all data on the enterprise network.

23. What is a major challenge when applying security patches in an OT environment?

• Patches are too expensive.
• There are no security patches for OT systems.
• The need for continuous operation means downtime for patching is unacceptable.
• Patches are too easy to install.

24. A remote access solution for an external vendor needing to service a PLC should ideally terminate in the:

• Level 4 Enterprise Network
• IDMZ (Level 3.5)
• Level 1 Control Network
• Level 0 directly

25. The Purdue Model is a conceptual framework, not a strict standard with mandatory compliance. True or False?

• True
• False

26. The flow of data in a well-architected Purdue Model is primarily:

• Unrestricted between all levels.
• Hierarchical, moving between adjacent levels through controlled conduits.
• From the internet directly to the sensors.
• Only from the bottom up (Level 0 to Level 4).

27. Which industrial protocol would you most likely find at the lower levels (0, 1, 2) of the model?

• HTTP (Web Traffic)
• FTP (File Transfer)
• Modbus/TCP or Profinet
• SMTP (Email)

28. Placing a data diode between the OT and IT network is a method to:

• Ensure data can flow in both directions freely.
• Allow only one-way data flow (typically from OT to IT) to prevent external commands.
• Amplify the network signal.
• Encrypt all traffic automatically.

29. The convergence of IT and OT has made the Purdue Model:

• Obsolete and useless.
• Even more critical as a foundational concept for securing converged networks.
• A model for physical security only.
• Relevant only for legacy systems.

30. A key goal of implementing the Purdue Model from a cybersecurity perspective is to reduce the:

• Number of employees.
• Attack surface of the control system.
• Physical size of the plant.
• Amount of data collected.