Industrial control systems, aviation operations technology, and healthcare medical devices share a common characteristic: they were designed for reliability and safety, not security. Connecting them to IP networks without an accompanying security architecture is creating a class of risk that conventional IT security programs are simply not equipped to address. The IT/OT convergence celebrated as an efficiency driver is also one of the most consequential attack surface expansions in the history of enterprise security.

Why OT Security Requires a Different Playbook

Conventional IT security operates on assumptions that do not hold in OT environments. Systems can be patched, rebooted, and replaced on a routine schedule. In OT, patching often requires taking operations offline — which means scheduled downtime windows that may occur once or twice a year, if at all. Many OT systems run on proprietary protocols that modern security tools cannot inspect without risking false fault conditions. A vulnerability scanner run against a programmable logic controller in a water treatment facility can trigger a process fault. The controls that protect IT environments are frequently incompatible with OT operational requirements.

A Risk-Based OT Security Framework

The Four OT Security Foundations

  • Asset inventory and passive network visibility: You cannot protect what you cannot see. Passive monitoring tools purpose-built for OT environments provide visibility without disrupting operations — this is the non-negotiable starting point.
  • Network segmentation aligned to the Purdue Model: IT and OT must be separated at the network layer with controlled, monitored crossing points. Uncontrolled IT-to-OT access is the most exploited pathway in OT incidents.
  • Controlled remote access: No standing VPN access to OT systems. Privileged access workstations for all OT connections. Session recording for all remote maintenance — vendor and internal alike.
  • OT-specific incident response: Safety first, environmental protection second, operational continuity third. Security does not top the priority hierarchy in OT incidents. Playbooks built on the IT model will create worse outcomes in an OT crisis.

The Regulatory Timeline Is Not Waiting

TSA cybersecurity directives for aviation and surface transportation, NERC CIP for energy utilities, and FDA cybersecurity guidance for connected medical devices are all tightening — with enforcement mechanisms attached. Organizations that have deferred OT security investment are finding that regulatory requirements are now forcing the issue on timelines that do not accommodate the phased, thoughtful approach that produces durable results. The time to build an OT security program is before a regulator or an adversary forces the question. By the time either arrives, the options available are considerably more expensive and considerably less effective.