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OT & Cyber-Physical Security Architecture

Securing the Operational Technology and Cyber-Physical Systems Behind Critical Operations

Operational technology and cyber-physical systems are the backbone of modern operations: manufacturing lines, energy generation and distribution, water and wastewater, oil and gas, healthcare delivery, transportation, building management, food and beverage. They run on long-lived equipment, on protocols that predate modern cryptography, in environments where downtime has direct safety, environmental, and economic consequences.


The threat landscape against these environments has changed. Ransomware crews target OT now: Colonial Pipeline, JBS, Norsk Hydro, MKS Instruments, and the steady stream of incidents that don't make headlines. Nation-State actors continue to invest in OT-specific capability. Adversaries are beginning to operationalize AI for industrial reconnaissance and OT-aware attacks. The architectural assumption that OT lives in its own air-gapped world hasn't held for a decade.


Our OT & Cyber-Physical Security Architecture service helps you design the security architecture for these environments. We assess your current state across OT, IoT, IIoT, building management, medical, and broader cyber-physical scope; design a target-state architecture aligned to IEC 62443, NIST SP 800-82, and the Purdue Model; evaluate the OT security vendor landscape vendor-neutrally; and deliver a phased roadmap that respects operational reality. TBDCyber doesn't sell or resell OT security tooling.

Our Approach
OT/CPS Discovery, Inventory
& Risk Assessment

  • Asset discovery and inventory across OT, IoT, IIoT, building management systems, medical devices, transportation systems, and broader cyber-physical scope.
     

  • Network architecture mapping aligned to the Purdue Enterprise Reference Architecture (the Purdue Model), Levels 0 through 5, plus the industrial DMZ.
     

  • Protocol-aware vulnerability assessment for OT-specific protocols including Modbus, DNP3, Profinet, BACnet, OPC UA, EtherNet/IP, and sector-specific protocols.
     

  • Risk analysis grounded in operational, safety, environmental, and business impact, not just CVE counts.
     

  • IT/OT convergence point assessment: where the boundary is supposed to be, and where it has eroded over years of "temporary" connections.
     

  • Third-party and vendor remote access mapping: typically the highest-risk pathway into OT environments and the one most organizations have least visibility into.




     

OT/CPS Architecture &
Segmentation Design

  • Reference architecture aligned to IEC 62443 (zone and conduit model), NIST SP 800-82, and the Purdue Model.
     

  • Network segmentation strategy across IT, industrial DMZ, supervisory, control, and process levels.
     

  • Industrial DMZ architecture between corporate IT and operational systems is the single most important architectural control that most environments still get wrong.
     

  • Secure remote access architecture for vendors, technicians, and engineers, replacing the typical VPN-and-shared-credential pattern with modern jumphost, ZTNA, and session-recorded access models.
     

  • Identity architecture for OT environments, including human technicians, contractors, vendors, and the often-overlooked non-human identities (PLCs, HMIs, historians, engineering workstations).
     

  • Zero Trust principles applied to OT: where they work cleanly, where they need adaptation for legacy equipment, and where operational realities require pragmatism over purity.
     

  • Cyber-physical safety integration: security controls must not introduce safety risk, and safety systems must remain isolated and authoritative.

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OT-Specific Threat &
Resilience Architecture

  • OT-specific threat modeling covering ransomware operations targeting OT, IT-to-OT lateral movement, supply-chain compromises of OT vendors and software, insider threats in industrial environments, and emerging AI-augmented attack patterns.
     

  • Detection architecture for OT: passive monitoring as the default, active scanning where operationally safe, and hybrid models for environments that can support both.
     

  • Backup, recovery, and resilience architecture for industrial control systems, including isolated, offline backups; validated recovery; and golden-image management for PLCs and HMIs.
     

  • Pre-staged incident response playbooks for OT scenarios, designed to integrate with TBDCyber's broader Incident Emergency Response and Compromise Assessment services in the event of a real incident.
     

  • AI in OT: AI-augmented OT-specific malware and reconnaissance as a growing attack surface, and AI/ML-driven anomaly detection in industrial protocol traffic as a defensive capability.
     

  • Clear differentiation from active threat hunting and threat intelligence work delivered through TBDCyber's OT Threat Analysis service.

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Compliance, Vendor Selection, Roadmap & Governance

  • Alignment with sector and regulatory frameworks: IEC 62443, NIST SP 800-82, NIST CSF profile for OT/ICS, NERC CIP for electric utilities, FDA cybersecurity guidance for medical device environments, TSA Pipeline Security Directives, NIS2 for European critical infrastructure, IMO maritime requirements, and emerging US sector-specific regulation.
     

  • Vendor-neutral evaluation across the OT security platform landscape based on environmental fit, deployment model (passive vs. active), and integration with your existing security stack.
     

  • Phased roadmap that respects operational reality.
     

  • OT security operating model and IT/OT collaboration framework.
     

  • Training and knowledge transfer for in-house OT engineers, IT security teams, and the bridge roles that have to operate across both worlds.
     

  • Connection to broader programs: Zero Trust Architecture Strategy (architectural anchor), Cyber Resilience Review (broader resilience), DR and BCP Management (operational continuity).

     

Benefits

Architecture for the OT Environment You Actually Have

Most OT security guidance assumes a clean Purdue Model. Your environment probably has 30 years of accumulated reality layered on top of it. We design architectures that work in the environment you operate, not the one in the textbook.

Aligned to the Standards Your Auditors and Regulators Expect

IEC 62443, NIST SP 800-82, NERC CIP, FDA cybersecurity guidance, TSA Pipeline Directives, NIS2. The architecture we design is mapped to the framework your sector and regulators actually use.

Pragmatic About Operational Reality

You cannot patch a control system mid-production run. You cannot air-gap a remote site that needs vendor support. You cannot replace 25-year-old equipment because it doesn't support modern cryptography. We build architectures that respect those constraints and design controls around them, not in spite of them.

Connected to Your Broader Zero Trust Program

OT and cyber-physical security are one pillar of a broader Zero Trust program. Where Zero Trust principles apply cleanly, we use them. Where they need adaptation for legacy or operational reasons, we adapt them. Either way, OT is part of the architectural conversation, not a separate world.

Related Services

OT & Cyber-Physical Security Architecture is one pillar of a broader Zero Trust program. Want to know more? See Zero Trust Architecture Strategy for the architectural anchor.

 

Need active threat hunting, intelligence, or detection work specific to OT? See OT Threat Analysis, the operational counterpart to this architectural service.

 

Investigating a suspected OT incident? See Compromise Assessment and Incident Emergency Response.

 

Need OT-specific incident plans and resilience? See Incident Planning, DR and BCP Management, and Cyber Resilience Review.

 

Concerned about identity in OT, including vendor and contractor access? See Identity Strategy and Privileged Access Management.

Most OT Architectures Were Designed When Air-Gapping Was Real.

Today's OT environments are connected to enterprise IT, accessed remotely by vendors, supported by software running in the cloud, and increasingly augmented by AI. The architectural assumption that OT lives in its own world hasn't held for a decade and adversaries from ransomware crews to nation-state actors are operationalizing that gap.


TBDCyber designs OT and cyber-physical security architectures that reflect today's reality: connected, complex, and contested. Anchored to IEC 62443, NIST SP 800-82, and the Purdue Model. Built to integrate with your broader Zero Trust program.
 

Talk to an OT Security Architect →

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