Industrial IoT Security Guide
Protecting OT Environments Without Stopping Innovation. Practical cybersecurity for industrial networks.
The Core Difference
IT security and OT security have fundamentally different priorities. IT prioritizes confidentiality. OT prioritizes availability — a compromised IT system loses data; a compromised OT system stops production or hurts people. Understanding this difference is the foundation of industrial cybersecurity.
1The IT/OT convergence security problem ↓
What is OT: the hardware and software that monitors and controls physical processes (PLCs, SCADA). Historically air-gapped from IT networks — now increasingly connected for IIoT data access.
Why OT security is different: OT devices run legacy operating systems (Windows XP, CE) that can't be patched because vendors won't certify patches. They can't be rebooted without stopping production. Most OT devices have no authentication — if you're on the network, you can issue commands.
The attack surface expansion: every IIoT sensor, gateway, and cloud connection is a potential entry point into your OT network.
2ISA/IEC 62443 — the standard that actually applies↓
What it is: the international standard for industrial cybersecurity. A series of standards covering security management systems, policies, and technical requirements for OT environments.
Why it matters more than NIST or ISO 27001: those frameworks were designed for IT. 62443 addresses OT-specific challenges like legacy systems, safety systems, and availability requirements.
The zone and conduit model: segmenting OT networks into zones (groups of assets with similar security requirements) with firewall-controlled conduits is the foundation of an OT security architecture.
3Network architecture — the technical foundation↓
The Purdue Model: Levels 0-5 from physical process to enterprise IT. The demilitarized zone (DMZ) at Level 3.5 between OT and IT networks is the critical control point for IIoT data flows.
What should cross the DMZ: IIoT telemetry data flows one-way from OT to IT. Commands and configuration changes to OT devices should never originate from IT networks.
Unidirectional security gateways: hardware-enforced one-way data flow from OT to IT. The strongest technical control against IT-side compromise reaching OT.
4Remote access security ↓
The remote access explosion: VPN connections to OT networks from vendor technicians, employees, and contractors are a primary attack vector.
Privileged Access Management (PAM) for OT: dedicated remote access solutions featuring session recording, just-in-time access, and no persistent connections.
Multi-factor authentication: MFA for all remote access to OT-connected systems is non-negotiable in modern deployments.