OT cybersecurity

In OT cybersecurity, we are the pragmatic ones

We find what matters, fix it without stopping the plant, and leave your team able to run it. Passive first, vendor-agnostic, and what you already own before anything new.

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IEC 62443NIST 800-82NCA OTCCNIS2NCIIPC

Zones & conduits enforcedZero production impactDefensible architecture

How we work

Four rules we keep on every plant

They are how we keep your plant running while we work on it, and why our advice does not end in a shopping list.

Passive by default

Assessments work from documents, interviews, configurations and network traffic. We never scan live controllers.

Testing only where it is safe

Penetration tests run during FAT, SAT or scheduled downtime, or in a test environment, under signed rules of engagement with stop conditions.

Vendor-agnostic

No vendor affiliation and no referral fees. We recommend what fits your plant, including lower-cost or open-source options.

What you own, first

Early fixes mostly use what you already have: firewall rules, switch settings, accounts and backups.

Services

Assess, transform, enable

Three stages, ten services. Most plants start on the left with an assessment, then move right: a funded plan, the fixes, and people who can keep it running.

Three plant projects, and what we chose not to do

AssessAssessments

Know exactly where you stand before spending a rupee on tooling.

Gap Assessment

A rapid review of architecture, governance and maturity gaps, with zero impact on operations.

For: Plants at the start of their OT security journey.
You get: An IEC 62443 maturity score, quick wins and a phased roadmap.
Length: 2 to 4 weeks

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Risk Assessment

Detailed, standards-driven validation (IEC 62443, NIST) through passive methods.

For: Plants that have closed the big gaps and need deep technical validation.
You get: A risk register scored for safety, operations, cost and compliance, an asset inventory and a treatment plan.
Length: 4 to 8 weeks

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Penetration Testing

Attack simulation during FAT, SAT or scheduled downtime, or in a test environment.

For: Mature environments with controlled test windows.
You get: Signed rules of engagement with stop conditions, and a report with scored findings.

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TransformTransformation

From findings to a funded, phased programme your board approves.

Strategy & Roadmap

Findings turned into a phased plan, with the money to buy and the money to run, ready for board approval.

For: Executives and CISOs who need a concrete, funded path.
You get: A 1, 3 and 5-year roadmap, budget by initiative, and a board-level business case.

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Cybersecurity Program

Governance, policies, and incident response planning for long-term security.

For: Organisations putting structure, process and people in place.
You get: Policies and procedures, an incident response plan, vendor access and change management.

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Cybersecurity Solutions

Vendor-agnostic deployment, from firewalls to the OT SOC, with no disruption to processes.

For: Plants deploying OT security technology, monitoring or a SOC.
You get: Technology selection, architecture design, staged deployment and tuned detection rules.

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EnableEnablement

People and muscle memory, trained on real PLCs, not slides.

Awareness Training

Fundamentals for plant and field staff: USB safety, threat recognition.

For: All plant, field and operational staff.
You get: An instructor-led session with real incident cases, and a certificate of completion.
Length: 4 hours

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Job Readiness Training

Role-specific defence skills for engineers taking on security duties.

For: OT engineers, operators, maintenance leads and system owners.
You get: Hands-on exercises, a risk assessment workshop as per IEC 62443-3-2, and a first-responder guide.
Length: 2 to 3 days

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Cybersecurity Testbeds

Portable, realistic OT testbeds with real PLCs and SCADA.

For: Training, attack simulation and technology evaluation.
You get: A testbed designed and built with real PLCs and SCADA, exercise scripts and team training.

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Incident Response TTX

High-pressure simulations testing technical and executive teams together.

For: Asset owners and executives who want to test their readiness.
You get: A scenario built from real OT campaigns, facilitation, and a prioritised improvement plan.
Length: Half a day to a full day

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Where to start

Start with your situation

Most plant engagements begin with one of these. If yours is not here, tell us what you are dealing with and we will point you to the right first step.

You do not know where you standGap Assessment The board wants a funded planStrategy & Roadmap An audit or a regulator is comingCybersecurity Program Your incident plan has never been testedIncident Response TTX

What we find

Four things we meet in almost every plant

And what we do about each. The first fixes are usually configuration changes on equipment you already own.

Systems that cannot be patched

Controllers on operating systems the vendor stopped supporting years ago.

Our answerWall them off. Their own zone, one controlled path in and out, and eyes on that path.

Poorly separated IT and OT boundaries

Historian links, vendor VPNs and convenience connections have quietly joined IT and OT into a single network.

Our answerDraw the zones, agree the conduits, then enforce them.

Remote access nobody watches

Vendor tunnels that never close, shared passwords, sessions nobody records.

Our answerOne door in, every session recorded, access that expires.

An incident response plan nobody has tested

A document written for the audit and kept in a folder. When something happens, the first hour goes on finding out who to call.

Our answerA plan written for your plant, then exercised with the people who will use it, until the first hour is routine.

Technology and standards

The defences we deploy, and how much each one matters

Solutions implementation

These are the technology categories behind our implementation work, placed where they belong on the Purdue model and rated by how critical each one is to a defensible plant. Everything is staged on our testbed before it touches production.

Network ProtectionIndustrial firewalls & segmentation

CriticalityCritical

Every other control assumes the plant is not flat. Segmentation is the first thing an assessment finds missing and the first thing an attacker exploits.

Stops

Internet-exposed controllers, IT ransomware spilling into the plant, lateral movement between units.

Secure Remote AccessBrokered, recorded vendor sessions

CriticalityCritical

Remote access is the most common confirmed entry point in industrial incidents. Standing VPN tunnels and shared vendor logins are the door attackers walk through.

Stops

Stolen VPN credentials, unmonitored vendor sessions, dormant accounts.

Backup & RecoveryController, HMI & server resilience

CriticalityCritical

Recovery time is the difference between a three-day restart and a five-week shutdown. Backups only count if the restore has been rehearsed.

Stops

Lost PLC logic and HMI projects, extended outages, ransom pressure.

OT IDS / MonitoringPassive visibility & threat detection

CriticalityImportant

You cannot defend assets you cannot see. Passive monitoring is the only way to get a true inventory and to notice a rogue Modbus write before the process does.

Stops

Unknown devices, protocol misuse, months-long dwell time.

Endpoint ProtectionHMI & engineering workstation hardening

CriticalityImportant

HMIs, historians and engineering stations are ordinary Windows machines that run for a decade unpatched. Allow-listing makes that survivable.

Stops

Ransomware execution, USB-borne malware, unauthorised engineering tools.

Specialized DefenseData diodes, USB kiosks & OT honeypots

CriticalityTargeted

For the paths a firewall alone does not close: a diode lets historian traffic leave L2/L3 for IT with no way back, a USB kiosk is the only route removable media takes to a Level 2 workstation, and a decoy SIS, DCS or IED gives an intruder something to touch and you an alert.

Stops

Traffic flowing back into OT, USB-borne malware, quiet lateral movement toward controllers.

USB scanning kioskOT honeypots

Industrial platforms we secure

OT security technologies we deploy

Standards and frameworks we map to

IEC 62443InternationalNIST 800-82USA / GlobalNCA OTCCSaudi ArabiaEU CRAEuropean UnionNIS2European UnionNCIIPCIndiaDESC ICSUAE / DubaiSEMI E187Semiconductor

Logos indicate technologies we work with, not endorsements. Client logos available on request.

Industries

Built around how your industry works

Each industry page walks through the process stage by stage, where it is exposed, and which of these services tackles each challenge.

View all industries

Power GenerationElectric UtilitiesOil and GasWater and WastewaterManufacturingChemicalPharmaceuticalFood and BeverageAutomotiveSemiconductorMiningAviationTransportMaritimeEmbedded Technology

Questions

What plant teams ask us first

What is the first step if we start OT cybersecurity for our plant today?

Find out what you actually have and where it is exposed, before buying anything. A gap assessment does exactly that: two to four weeks, fully passive, ending in a prioritised list of what to fix first and what it will roughly take. Most plants discover the first few fixes are configuration changes on equipment they already own, not new products.Gap Assessment

How do I justify OT security spend to my board?

Who should be responsible for OT cybersecurity: IT or Instrumentation?

Which OT monitoring platform should we choose: Claroty, Nozomi or Dragos?

Will an OT security assessment disrupt our operations?

My PLCs are 20 years old and cannot be patched. What can I do?

How much does an OT security assessment cost and how long does it take?

Talk to RelyBlue

Tell us about your plant

Where it is, what runs it, and what worries you. One conversation with a senior advisor, no sales pressure.

You talk to a senior advisor, never a salesperson