OT and ICS cyber security, IEC 62443-aligned.
Risk assessments, network segmentation, monitoring, IR planning and tabletop exercises for manufacturing, energy, oil & gas, transport and healthcare infrastructure. Aligned to IEC 62443 and NIST SP 800-82r3.
What we mean by OT cyber security
Operational Technology cyber security is the discipline of defending control systems — the PLCs, DCSs, SCADA, building automation, and the networks that connect them — against deliberate compromise. It is adjacent to IT cyber security but the failure modes are different: safety, environmental, and production-impact consequences sit alongside the usual confidentiality, integrity, and availability triad.
Engagements are aligned to IEC 62443-2-1:2024 (security program requirements for IACS asset owners), IEC 62443-3-3:2013 (system security requirements and security levels), and NIST SP 800-82 Rev 3 (the September 2023 current revision of the Guide to Operational Technology Security).
Key facts
- IEC framework
- 62443
- NIST guide
- 800-82r3
- Industries served
- 5
- Recommended cadence
- Annual
What we do
Four headline service modes, each scoped to your control system environment.
OT risk assessment
Asset inventory, threat assessment, IEC 62443 zone-and-conduit modelling. Output is a prioritised risk register tied to the control architecture.
Network segmentation review
Validate Purdue Model layering and IEC 62443 zone boundaries. Identify cross-boundary flows that should not exist and harden those that should.
OT monitoring & detection
Passive monitoring deployment for OT-aware visibility. Detection content tuned to ICS protocols and operational baselines, not adapted IT signatures.
OT tabletop exercises
Scenario-based exercises spanning IT/OT communication paths, safety considerations, and production-impact decision making.
Industries we cover
Five sectors where OT cyber security is the dominant cyber risk picture. Each has distinctive control-system patterns and regulatory drivers.
Manufacturing
PLC and DCS environments, MES integration, IT/OT boundaries.
Energy & utilities
SCADA, smart-grid components, NIS-CAF obligations.
Oil & gas
Process control, remote facility connectivity, safety-instrumented systems.
Transport & logistics
Building automation, fleet telematics, depot OT.
Healthcare infrastructure
Building management, medical-device networks, BMS-to-IT bridging.
How an engagement runs
Five stages from scoping to annual exercise.
- 1
Scoping call
30 minutes, freeSite type, control system inventory, regulatory driver, current monitoring posture. We learn what kind of OT environment we are walking into before we propose anything.
- 2
OT risk assessment
Scope-dependentOn-site and remote assessment. Asset inventory, threat assessment, IEC 62443 zone-and-conduit modelling. Output is a prioritised risk register.
- 3
Roadmap & remediation plan
Scope-dependentPrioritised plan covering segmentation, monitoring, patching constraints, and incident response. Cost-vs-impact trade-offs explicit.
- 4
Implementation & monitoring setup
VariableNetwork segmentation work, monitoring deployment, change-management hooks. We work alongside your engineering team rather than throwing recommendations over the wall.
- 5
OT tabletop exercise
AnnualScenario-based exercise covering IT/OT incident communication paths. Safety, environmental and production-impact dimensions all included.
Capabilities
Six capability areas covered. Most engagements deliver several; some focus on one.
OT Risk Assessment
Comprehensive risk analysis covering asset inventory, threat assessment, IEC 62443 zone & conduit modelling, and impact assessment.
Network segmentation review
Validate IEC 62443 zones and conduits, Purdue Model layering, and cross-boundary flow controls. Output is a remediation plan with prioritised segmentation actions.
OT monitoring & detection
Passive OT-aware monitoring deployment, baseline establishment, detection content tuned to ICS protocols. Integrates with existing SIEM where present.
OT incident response planning
Custom incident response plans, comprehensive playbook development, and tabletop exercises that account for safety, environmental, and production impact.
Tabletop exercises
Scenario development, facilitated exercises, role-based simulations, post-exercise analysis. Cover IT/OT communication paths and joint decision making.
Compliance support
Documentation, audit support, and ongoing monitoring against IEC 62443-2-1:2024, NIST SP 800-82r3, and where applicable NIS-CAF.
Why 1 Sequence Cyber
Standards-aligned
Programmes aligned to IEC 62443-2-1:2024 (security program requirements for IACS asset owners), IEC 62443-3-3:2013 (system security requirements and security levels), and NIST SP 800-82 Rev 3 (September 2023, current revision).
Cross-disciplinary delivery
OT cyber security is not just IT applied to PLCs. We treat it that way — joint sessions with operations, engineering, safety and security, because the failure modes that matter aren't only confidentiality and integrity. Cross-link with our NIS-CAF service for UK regulated OT operators.
Ready to scope OT cyber work?
Tell us your sector, your control system architecture at a high level, and what is driving the requirement. We’ll come back with a proposal within 48 hours.
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