EC-Council Certified Ethical Hacker (CEH) v12Mobile Platform, IoT, and OT HackingMedium

A critical infrastructure organization is implementing a new Supervisory Control and Data Acquisition (SCADA) system for its power grid. To enhance security, they are considering a network architecture that physically separates the operational technology (OT) network from the information technology (IT) network, allowing one-way data flow from OT to IT, but strictly preventing any direct inbound connections from IT to OT. Which of the following security concepts does this architecture BEST exemplify?

  1. AVirtual Local Area Network (VLAN)
  2. BNetwork Access Control (NAC)
  3. CDMZ implementation
  4. DAir gapping with a data diode
Show answer & explanation

Correct answer: D. Air gapping with a data diode

The description of physically separating networks and allowing one-way data flow from OT to IT while preventing inbound IT to OT connections is the definition of an air gap, specifically implemented with a data diode to ensure unidirectional communication.

Why the other options are wrong

  • A. VLANs segment a network logically, but they don't provide the physical separation or strict one-way data flow described for critical OT environments.
  • B. NAC controls who can connect to a network but doesn't inherently enforce physical separation or one-way data flow between distinct networks.
  • C. A DMZ (Demilitarized Zone) is a buffer network, but it typically allows two-way traffic for certain services, not strict one-way flow for OT protection.

Air Gap with Data Diode (OT Security)

An air gap is a security measure that isolates a secure network from unsecured networks. A data diode is a hardware device that enforces unidirectional data flow, often used to bridge an air gap for monitoring purposes without allowing reverse communication.

  • Provides extreme network isolation for critical systems.
  • Data diodes are hardware-enforced, preventing software misconfiguration.
  • Commonly used in OT/ICS environments to protect against cyberattacks from IT networks.

Memory trick: Separate critical controls like a power plant, with a one-way gate for safety.

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