Attack Readiness

OT vulnerabilities have
physical consequences.

Security testing of industrial control systems with methodologies designed for OT environments. Operational continuity is the priority throughout.

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What is an OT pentest?

You know your OT environment controls physical processes. You have IT/OT convergence bringing new connectivity to your production floor. You get a controlled assessment of your OT security without disrupting operations. An OT pentest tests the IT/OT boundary, network segmentation, and the security of individual OT components using methodologies adapted to industrial environments. Passive analysis, controlled active testing, and detailed reporting with operationally feasible recommendations.

About this service

OT Pentest: security testing for industrial environments

Operational technology controls physical processes: production facilities, power plants, water treatment, logistics systems. A vulnerability in OT has direct physical consequences. An OT pentest examines the security of your industrial control systems with the care these environments require.

OT environments are fundamentally different from IT. Availability takes precedence over confidentiality. Systems sometimes run for decades without updates. Protocols such as Modbus, OPC UA, and Profinet were not designed with security in mind. The team understands this context and tests with adapted methodologies that account for operational reality.

DEFION has specific OT security experience in manufacturing, energy, water, and transport environments. The team knows the protocols, the systems, and the operational constraints. Testing focuses on the IT/OT boundary, OT network segmentation, and the security of individual components without risking operational continuity.

Why this matters

Three OT security risks that grow with IT/OT convergence

  • The IT/OT boundary is the primary attack path

    Remote access, historian servers, and IT/OT integration points are how attackers cross from IT to OT. A single misconfigured firewall rule or unpatched engineering workstation can be the bridge to your production systems.

  • OT protocols have no authentication

    Modbus, DNP3, and many other industrial protocols transmit commands without authentication. Anyone who reaches the OT network can send commands to PLCs and HMIs. Segmentation is the only defence.

  • OT systems cannot be patched like IT

    Production continuity requirements, vendor support constraints, and certification dependencies mean OT systems run known vulnerabilities for years. Compensating controls and segmentation are critical but often untested.

What gets tested

Scope of the OT pentest

IT/OT boundary and DMZ configuration
OT network segmentation (Purdue model)
SCADA/HMI systems
PLCs and RTUs (passive analysis)
OT protocols: Modbus, OPC UA, DNP3, Profinet, EtherNet/IP
Engineering workstations
Historian servers and IT data connections
Remote access solutions for OT
Physical security of OT components
Methodology

How DEFION conducts an OT pentest

01

Scoping and risk analysis

Inventory of OT environment, process-critical systems, constraints, and test windows.

02

Passive reconnaissance

Network monitoring without active scans, protocol analysis, and asset discovery.

03

Controlled active tests

Targeted tests on the IT/OT boundary and non-critical components, avoiding production risk.

04

Segmentation validation

Verifying whether IT and OT networks are correctly separated according to the Purdue model.

05

Protocol analysis

Reviewing OT protocol implementations and communication flows for security weaknesses.

06

Reporting

Report with findings, risk assessment, and OT-specific remediation steps that account for operational constraints.

What you receive

Deliverables

  • Executive summary suitable for plant management and board
  • Technical report with OT-specific findings
  • Network segmentation assessment (Purdue model)
  • IT/OT boundary analysis
  • Remediation plan accounting for operational constraints and maintenance windows
  • Report debrief with OT and IT teams
Target audience

Who is an OT pentest for?

Any organisation with industrial control systems faces OT security risks. IT/OT convergence has brought OT into the attack scope of threat actors who previously focused only on IT systems.

  • Manufacturing companies with automated production processes
  • Energy companies and utilities
  • Water treatment and distribution companies
  • Logistics and transport sector
  • Organisations that need to demonstrate NIS2 or IEC 62443 compliance
Frequently asked questions

FAQ

Is an OT pentest safe for my production environment?
Yes. The team uses adapted methodologies that prioritise operational continuity. Aggressive tests on process-critical systems are not performed. Active tests are limited to non-critical systems and the IT/OT boundary. Passive analysis provides insights without risk.
Can the test take place during production?
Passive analysis yes. Active tests are preferably performed during planned maintenance windows or on non-production systems. The test plan is coordinated with your operational schedule.
What if our OT environment contains legacy systems?
That is the rule rather than the exception in OT. The team has experience with legacy systems and knows how to test them safely. Recommendations account for the reality that patching is often not possible; compensating controls are included.
Should both IT and OT teams be involved?
Yes. An OT pentest touches both domains. The team works with both IT and OT and ensures findings and recommendations are usable for both teams.
How does an OT pentest relate to IEC 62443 compliance?
An OT pentest can be part of an IEC 62443 compliance programme. It validates whether the technical security measures that IEC 62443 requires are actually effective. Findings can be mapped directly to IEC 62443 security levels.
OT Red Teaming

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Internal Pentest

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External Pentest

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Ready to test your OT security?

Tell us about your environment and operational constraints. We design the right approach together.

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