What you'll learn
- Why OT is different
- Purdue model and IEC 62443
- Lessons from the refrigeration attacks
- IoT basics
Lessons
1Why OT is different
Safety and availability come before confidentiality. Systems run for 15–30 years, patching windows are rare, and many protocols (Modbus, DNP3, older PROFINET) lack authentication.
2Purdue model and IEC 62443
Levels 0–1 (process, controllers), 2 (HMI/SCADA), 3 (site operations), 3.5 (industrial DMZ), 4–5 (enterprise). IEC 62443 groups assets into zones with defined conduits and target Security Levels (SL1–SL4).
3Lessons from the refrigeration attacks PRO
In Oct–Nov 2026, internet-reachable refrigeration controllers at supermarkets in France and across Europe were manipulated, spoiling stock, and blood-bank systems were also targete…
Continue this lesson in the platform →4IoT basics PRO
Unique credentials per device, signed firmware updates, network isolation (separate VLAN/SSID), and an SBOM from the vendor. The EU Cyber Resilience Act now places security duties …
Continue this lesson in the platform →Hands-on lab: Inventory and segment your home IoT
- List every connected device at home (TV, camera, plugs, router).
- Check your router's client list for unknown devices.
- Change default passwords and enable automatic firmware updates.
- Move IoT devices to a guest or IoT network.
- Check shodan.io for your own public IP to confirm nothing is exposed.
Outcome: A segmented, inventoried home network, the same steps you'd apply to a plant.
Practice questions
In OT, which property usually comes first?
Answer: Safety/Availability. Physical processes and people come first.
Purdue level 3.5 is…
Answer: Industrial DMZ. Buffer between IT and OT.
IEC 62443 groups assets into…
Answer: Zones and conduits. Zones joined by controlled conduits.
The full graded assessment (4 questions, pass mark 70%) is in the platform.
Key terms
- Purdue model
- Reference architecture of OT network levels 0–5 with an industrial DMZ at 3.5.
- PLC
- Programmable Logic Controller running industrial processes.
- HMI
- Human-Machine Interface operators use to monitor and control processes.
- SCADA
- Supervisory Control and Data Acquisition systems for distributed processes.
- Modbus
- Common ICS protocol with no built-in authentication.
- Zones and conduits
- IEC 62443 grouping of assets (zones) and their controlled communications (conduits).
- Safety Instrumented System
- Independent system that brings a process to a safe state.
See the full cyber security glossary →