How targeted penetration tests secure industrial systems. Methods, requirements and best practices for machine builders, including CRA, IEC 62443 and safety aspects.
Contents
Attacks on industrial systems are increasing – with real-world consequences
Industrial IT and OT systems are increasingly the target of targeted cyberattacks. According to the “X-Force Threat Intelligence Index 2025” by IBM (https://www.ibm.com/thought-leadership/institute-business-value/en-us/report/2025-threat-intelligence-index), the manufacturing sector was again the most affected industry worldwide, accounting for 40% of all recorded attacks. What makes the industrial environment special is that a successful attack can not only compromise data but also affect physical processes.
It becomes particularly critical when cyberattacks impact safety‑related functions. If safety controllers, emergency‑stop chains or controlled machine movements are manipulated, there is an immediate danger to people and equipment. Additional risks include production outages, quality problems or espionage. The consequences range from economic losses to liability risks for manufacturers and operators.
Regulatory pressure requires technical testing
With the new Machinery Regulation, the Cyber Resilience Act (CRA) and the delegated regulation to the Radio Equipment Directive (RED DA), legislators are reacting to these developments. Manufacturers of machines and connected devices are obliged to assess cyber risks and implement technical protective measures — and to demonstrate their effectiveness. Security assessments such as penetration tests are a central element of that proof.
Relevant standards such as IEC 62443, EN 18031 or EN 50742 explicitly require that products and systems be tested for vulnerabilities — especially where risks to safety, availability or confidentiality exist.
Whether and to what extent penetration tests are required to provide evidence under the CRA, the Machinery Regulation or RED DA is not always clear-cut. If you want to classify this question for your products, a short orientation discussion can help.
Why penetration tests are indispensable in IIoT and OT environments
Security requirements for connected industrial systems are rising — not only because of regulatory demands, but also because the technical interdependencies between IT, OT and IIoT are increasing. Penetration tests help to uncover existing weaknesses in a targeted way before they lead to a real security incident.
They make a concrete contribution to protecting critical infrastructures, minimizing risk and strengthening product responsibility. Whether a control panel, a connected device or an embedded component: tests under realistic conditions reveal how robust the product actually is against targeted attacks.
Particularly important is identifying errors that were overlooked during development or not detected in validation tests — for example insufficient authentication mechanisms, lack of hardening or insecure firmware communication. A professionally conducted penetration test makes these weaknesses transparent and provides actionable recommendations.
OT penetration tests require specialized know‑how
Planning an OT or IIoT penetration test requires close coordination with development, engineering, product management and, if applicable, safety teams. The goal is to analyze relevant systems in a targeted way without endangering the function of safety‑critical or production‑related components.
A clear definition of the test scope (scoping) is crucial: which components should be tested? Which scenarios are realistic? Which interfaces are particularly critical? Equally important: the test period must be coordinated with the product team so that potential impacts are technically mitigated in advance — for example through tests in lab or reference environments.
Integrating a simplified threat model as part of the scoping helps systematically identify attack paths and define realistic test objectives — not as a blanket “black box”, but product‑centric, focused and reproducible.
In industrial environments, proper scoping determines the value of a penetration test. We are happy to discuss without obligation which test depth and scenarios make sense for your IIoT or OT systems.
Typical process of an industrial penetration test
Penetration tests in industrial environments differ fundamentally from classic IT tests. The aim is not primarily to demonstrate the maximum potential damage, but to systematically find security‑relevant weaknesses under realistic conditions — especially those not detected during development or testing. The focus is on targeted lab tests and a structured root‑cause and risk analysis.
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Scoping with scenarios and threat modeling
At the start, concrete test objectives, assets to protect and attack vectors are defined together with the manufacturer. Simplified threat models are used, based on realistic attack scenarios — for example remote access to a machine, sabotage via maintenance interfaces or data exfiltration via cloud gateways. The scope is defined so that safety‑relevant components and functions are the focus, e.g. controllers, communication interfaces or HMI systems.
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Lab‑based execution
The actual test takes place in an isolated environment — either on a test device, a lab configuration or a digital twin. This allows targeted analysis of security‑relevant weaknesses without endangering the real production system. The emphasis is on weaknesses in authentication, access control, communication security or logic errors in the implementation of safety‑critical functions.
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Analysis of findings: root cause and impact
Unlike classic penetration tests, the emphasis is not only on discovery but also on understanding the cause. For each finding, a structured root‑cause analysis is performed: was it an architectural flaw? An implementation error? A configuration deficiency? In addition, the concrete impact is analyzed systematically: which functions would be affected? Would safety be impacted? How large is the realistic risk in case of misuse?
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Risk‑based prioritization and improvement of development
Identified vulnerabilities are assessed and prioritized according to their criticality. The final report contains not only technical details and reproduction instructions, but concrete recommendations for remediation — with a focus on sustainably improving development and testing processes. The goal is not only to close the discovered flaws but to avoid similar errors in the future.
Selection criteria what qualifies providers of industrial penetration tests
The quality of an OT or IIoT penetration test depends entirely on the know‑how of the test team. Unlike classic IT pentests, technical tool knowledge alone is not sufficient. What matters is a deep understanding of industrial systems, development processes and regulatory requirements.
A qualified provider brings the following competencies:
- Experience with industrial controllers, communication protocols and security architectures — e.g. working with PLCs, HMIs, fieldbus systems, proprietary protocols or safety‑oriented control technology.
- Expertise in test design and execution under lab conditions, to investigate vulnerabilities in a targeted and controlled manner — without risk to ongoing operations.
- Ability to perform root‑cause analysis, i.e. structured investigation of the causes of identified vulnerabilities — such as architecture, implementation or configuration issues.
- Understanding of functional safety and safety‑relevant requirements, to correctly assess interactions between security and safety.
- Experience with regulatory requirements such as the Cyber Resilience Act (CRA), the Machinery Regulation, the Radio Equipment Directive as well as relevant standards like IEC 62443, EN 18031 or EN 50742.
Professional providers do not just deliver a list of technical vulnerabilities; they clearly show where gaps exist in development or testing — and how to avoid them going forward.
Best practices how companies get the most out of a pentest
To ensure a penetration test in an industrial environment is more than a one‑off compliance exercise, it should be embedded into product development, quality assurance and security strategy. The goal is not only to close individual vulnerabilities but to structurally improve product security.
- Plan tests early
Penetration tests should not take place only at the end of a project. Especially for new developments or major changes (e.g. new communication modules, remote interfaces, cloud integration), a test before market launch is recommended — ideally in parallel with internal verification to uncover overlooked weaknesses. - Use lab environments
For OT systems, a controlled test environment with realistic components is recommended — e.g. labs with typical controllers, IIoT gateways or simulated machine processes. This identifies security‑relevant weaknesses without endangering productive systems. - Feed results back into development processes
Insights from the test should flow into lessons learned, secure coding guidelines or architecture design. For recurring weaknesses, it is worthwhile to supplement internal test and approval processes. - Assess and prioritize risks transparently
A raw “vulnerability listing” is not sufficient. Test results must be evaluated in terms of safety, availability, manipulation potential and regulatory relevance — and presented so that technical decision‑makers and management can understand them. - Continuity instead of a one‑off action
Even with limited resources: penetration tests should be carried out regularly — e.g. annually or risk‑based by product group. As maturity grows, tests can be integrated into internal verification steps (e.g. integration tests) or used as templates for certifications.
Conclusion play it safe from a security perspective
In industrial environments, penetration tests are far more than a mere inspection procedure — they are a central instrument for assuring the quality of safety‑relevant systems. When used correctly, they not only uncover vulnerabilities but also enable understanding of their root causes and targeted improvement of development processes.
Especially in the context of increasing connectivity, growing regulatory requirements (e.g. Cyber Resilience Act (CRA), Machinery Regulation) and the critical importance of safety functions, a structured, risk‑based and technically sound testing approach is essential. Those who test OT and IIoT systems deliberately protect not only systems and data but also operations, reputation and market access.
Penetration tests in mechanical engineering are not an end in themselves but part of a comprehensible security and evidence strategy. If you want to clarify how tests can be sensibly integrated into your product development and regulatory preparation, a non‑binding conversation is recommended.
