New Research: A Zero Trust Blueprint for OT System Security
We’re pleased to announce the release of new research from Numberline Security that addresses a clear gap in modern cybersecurity: applying Zero Trust principles to Operational Technology (OT) environments. Thanks to Appgate for sponsoring this work.
Building on Our Enterprise Foundation
This new research paper, “A Zero Trust Blueprint for OT System Security: Rationale, Phases, and ZTNA Platform Requirements,” builds directly on Numberline’s proven enterprise Zero Trust Blueprint, which helps organizations successfully implement Zero Trust initiatives. However, we recognized that while Zero Trust principles are universally applicable, the unique characteristics of OT environments demand specialized guidance and approaches.
Therefore, we took on the task of writing about how organizations can most effectively apply Zero Trust security strategies to operational technology systems, in ways that are different from a standard enterprise IT environment.
The Imperative: OT Deserves Zero Trust, Too
The motivation behind this research is clear and urgent. Historically, OT systems were protected by physical isolation—the “air gap” that made them unreachable from the outside world. But two fundamental shifts have rendered this approach dangerously obsolete:
IT/OT Convergence: The integration of information technology and operational technology networks has opened previously isolated OT systems to enterprise-level threats. What were once separate security domains have unfortunately become a unified attack surface.
Cloud Connectivity: Modern OT systems increasingly require remote access for maintenance, monitoring, software updates, and distributed management. While these capabilities enable unprecedented operational efficiency, they also expose OT systems to internet-based threats that were never part of the original design consideration.
As we state in the research: “OT deserves Zero Trust, too.” Given the critical nature of many operational systems and their traditional security weaknesses, OT environments may represent the domain where Zero Trust principles can deliver the most significant security improvements.
Adapting the Blueprint for OT
Our research introduces a modified Zero Trust Blueprint, tailored for OT environments:
Phase 1: Assessment – Evaluating organizational readiness and OT-specific security maturity
Phase 2: Strategy – Creating focused Zero Trust vision and cross-functional program governance
Phase 3: Roadmap – Developing dual roadmaps for access policies and technology changes
Phase 4: Execution – Deploying changes and enabling policy enforcement with OT-appropriate metrics
One particularly important aspect we emphasize is the dual roadmap approach in Phase 3. Unlike traditional IT projects, Zero Trust for OT requires understanding the dependency between enforced access policies (the actual security delivery mechanism) and the underlying technology and process capabilities that enable those policies.
We’ve found that there are actually two related roadmaps in any Zero Trust initiative: an Access Policy Roadmap (when policies are enforced) and a Technology and Process Change Roadmap (enabling required capabilities). The Access Policy Roadmap can only activate policies that utilize fully available capabilities in the enterprise’s ecosystem. Policies requiring immature or non-existent capabilities must wait until the parallel Technology and Process Change Roadmap readies those capabilities.
This dual roadmap recognition is especially critical for OT environments, where operational constraints and safety requirements make it essential to carefully sequence technology changes before policy enforcement can begin.
OT-Specific ZTNA Requirements
This research also identifies specific Zero Trust Network Access (ZTNA) platform requirements that are unique to or especially important for OT environments. These go beyond standard enterprise IT requirements to address OT’s distinctive operational, safety, and reliability needs.
For example, Network Time Synchronization represents a critical difference between enterprise IT and OT requirements. While enterprise IT environments typically utilize standard Network Time Protocol (NTP) servers, many OT environments require more precise time synchronization using the Precision Time Protocol (PTP).
When evaluating ZTNA vendors for OT deployment, organizations must ensure that vendor components support their preferred time synchronization scheme and associated network protocols. Critically, ZTNA vendors must not impose additional or unexpected latency on time synchronization network traffic, as this could significantly impact OT system performance or even cause system alerts, failovers, or shutdowns.
This is just one example of how the unique characteristics of OT systems require specialized consideration when implementing Zero Trust architectures.
Take Action: Read the Full Research
This blog post only scratches the surface of our comprehensive research. The full white paper provides detailed guidance on organizational readiness assessments, OT-specific maturity models, complete ZTNA platform requirements, and practical implementation strategies.
Download the complete “Zero Trust Blueprint for OT System Security” research paper here to access the full methodology, detailed requirements, and actionable guidance for protecting your critical operational infrastructure.
The convergence of IT and OT networks, combined with increasing cloud connectivity, has made Zero Trust adoption not just beneficial but essential for protecting critical operational infrastructure. With proper planning and OT-adapted approaches, organizations can achieve both enhanced security and operational excellence.