Penetration Testing for Machine Builders and IIoT Products
Penetration tests show machine builders and manufacturers of connected industrial products where their systems can be attacked before an attacker finds out. Production plants are increasingly networked, industrial internet of things (IIoT) devices are being integrated, and operational technology (OT) systems are being modernized. This brings efficiency and new products, but it also opens new attack vectors. In this environment, penetration testing has become an essential tool for keeping industrial systems secure and intact.
Contents
- Attacks on industrial systems are rising, with real consequences
- Regulatory pressure calls for technical testing
- Why penetration testing is essential in IIoT and OT environments
- OT penetration testing requires specialist expertise
- How an industrial penetration test typically runs
- What to look for in a provider of industrial penetration tests
- Good practice: getting the most out of a pentest
- Testing as part of quality assurance
Attacks on industrial systems are rising, with real consequences
Industrial IT and OT systems are increasingly the target of deliberate cyberattacks. According to IBM's X-Force Threat Intelligence Index 2025, manufacturing was once again the most attacked sector worldwide, with 40% of all recorded attacks. What sets the industrial environment apart is that a successful attack can do more than compromise data. It can also affect physical processes.
The situation becomes critical when cyberattacks affect safety-related functions. If attackers manipulate safety controllers, emergency stop circuits, or controlled machine movements, people and equipment are in immediate danger. Further risks include production downtime, quality problems, and espionage. The consequences range from financial damage to liability risks for manufacturers and operators.
Regulatory pressure calls for technical testing
Legislators have responded with the new Machinery Regulation, the Cyber Resilience Act (CRA), and the delegated act under the Radio Equipment Directive (RED). Manufacturers of machinery and connected devices must assess cyber risks, implement technical protective measures, and demonstrate that these measures work. Security testing such as penetration testing is a central part of that evidence.
Relevant standards such as IEC 62443, EN 18031, and EN 50742 also explicitly require products and systems to be tested for vulnerabilities, especially where there are risks to safety, availability, or confidentiality.
Whether penetration tests are needed as evidence under the CRA, the Machinery Regulation, or the RED delegated act, and to what extent, is not always clear. If you want to assess this question for your products, a short call can help.
Why penetration testing is essential in IIoT and OT environments
Security requirements for connected industrial systems are rising. This is partly due to regulation, and partly because the technical dependencies between IT, OT, and IIoT keep growing. Penetration tests help uncover existing weaknesses before they lead to a real security incident.
They make a concrete contribution to protecting critical infrastructure, reducing risk, and strengthening product responsibility. Whether the product is industrial switchgear, a connected device, or an embedded component, tests under realistic conditions show how well it actually withstands targeted attacks.
The focus should be on flaws that were overlooked during development or missed in validation testing. Typical examples are weak authentication, missing hardening, or insecure firmware communication. A professionally conducted penetration test makes these weaknesses visible and delivers recommendations you can act on.
OT penetration testing requires specialist expertise
Planning an OT or IIoT penetration test requires close coordination with development, engineering, product management, and, where relevant, safety teams. The aim is to analyze the 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 decisive:
- Which components should be tested?
- Which scenarios are realistic?
- Which interfaces are particularly critical?
The test period must also be agreed with the product team, so that potential effects are technically contained in advance, for example by testing in a lab or reference environment.
A simplified threat model as part of scoping helps identify attack paths systematically and define realistic test objectives. The test is then not a generic “black box” exercise but close to the product, focused, and traceable.
In an industrial environment, the right scoping determines how much value a penetration test delivers. We are happy to discuss in a no-obligation call which test depth and which scenarios make sense for your IIoT or OT systems.
How an industrial penetration test typically runs
Penetration tests in an industrial environment differ fundamentally from conventional IT tests. The main goal is not to show the maximum possible damage. It is to find security-relevant weaknesses systematically under realistic conditions, especially those that development or testing did not catch. The focus is on targeted lab testing and a structured analysis of causes and risks.
1. Scoping with scenarios and threat modeling
At the start, the tester and the manufacturer define specific test objectives, assets to protect, and attack vectors. Simplified threat models based on realistic attack scenarios support this, for example remote access to a machine, sabotage through maintenance interfaces, or data exfiltration through cloud gateways. The scope is set so that security-relevant components and functions are in focus, such as controllers, communication interfaces, or HMI systems.
2. Lab-based testing
The actual test takes place in an isolated environment: on a test device, a lab configuration, or a digital twin. Here, security-relevant vulnerabilities can be analyzed in a targeted way without endangering the real production system. The focus is on weaknesses in authentication, access control, and communication security, and on logic errors in the implementation of safety-critical functions.
3. Analysis of findings: root cause and impact
Unlike conventional penetration tests, the focus is not only on finding weaknesses but also on understanding their cause. Each finding goes through a structured root cause analysis: was it an architecture flaw, an implementation error, or a configuration weakness? The actual impact is also analyzed systematically. Which functions would be affected? Would safety be affected? How high is the realistic risk if the weakness were exploited?
4. Risk-based prioritization and better development
The vulnerabilities found are rated by criticality and prioritized. The final report contains technical details and steps to reproduce, and also specific recommendations for remediation, with a focus on lasting improvements to development and test processes. The aim is not only to fix the flaws found but to prevent similar flaws in the future.
What to look for in a provider of industrial penetration tests
The quality of an OT or IIoT penetration test depends on the expertise of the test team. Unlike in conventional IT pentests, knowing the tools is not enough. A deep understanding of industrial systems, development processes, and regulatory requirements is essential.
A qualified provider brings the following skills:
- Experience with industrial controllers, communication protocols, and security architectures, for example PLCs, HMIs, fieldbus systems, proprietary protocols, or safety-related control technology.
- Skill in designing and running tests under lab conditions, so that vulnerabilities can be examined in a targeted and controlled way without risk to ongoing operations.
- Ability to perform root cause analysis, that is, to investigate the causes of identified vulnerabilities in a structured way, for example in architecture, implementation, or configuration.
- Understanding of functional safety and safety-related requirements, so that interactions between security and safety are assessed correctly.
- Experience with regulatory requirements such as the Cyber Resilience Act, the Machinery Regulation, and the Radio Equipment Directive, and with the relevant standards such as IEC 62443, EN 18031, or EN 50742.
Professional providers do more than deliver a list of technical vulnerabilities. They show in a structured way where the gaps in development or testing are and how to avoid them in future.
Good practice: getting the most out of a pentest
For a penetration test in an industrial environment to be more than a one-off piece of evidence, it should be embedded in product development, quality assurance, and security strategy. The aim is not only to close individual vulnerabilities but to improve product security structurally.
- Plan tests early
Penetration tests should not wait until the end of a project. For new developments or fundamental changes, such as new communication modules, remote interfaces, or cloud connectivity, a test before placing on the market is advisable. Ideally, it runs in parallel with internal verification to uncover weaknesses that would otherwise go unnoticed. - Use lab environments
For OT systems, a controlled test environment with realistic components is advisable, for example labs with typical controllers, IIoT gateways, or simulated machine sequences. This lets you identify security-relevant weaknesses without endangering production systems. - Feed results back into development
Insights from the test should flow into lessons learned, secure coding guidelines, or the architecture design. Where vulnerabilities recur, it pays to extend the internal test and release processes. - Assess and prioritize risks in a traceable way
A plain vulnerability list does not help much. Test results must be rated for their relevance to safety, availability, manipulation, and regulation, in a way that technical decision-makers and management can follow. - Make testing continuous, not a one-off
Even with limited resources, penetration tests should take place regularly, for example once a year or risk-based by product group. As maturity grows, tests can move into internal test activities (such as integration tests) or serve as a basis for certification.
Testing as part of quality assurance
In industrial environments, penetration tests are much more than a test procedure. They are a central tool for the quality assurance of security-relevant systems. Used well, they not only uncover vulnerabilities but also reveal their causes, so you can improve development processes in a targeted way.
Connectivity is growing, and so are regulatory requirements such as the CRA and the Machinery Regulation. Safety functions play a critical role. What counts is a structured, risk-based test approach built on solid technical understanding. If you test OT and IIoT systems in a targeted way, you protect more than systems and data. You also protect operations, reputation, and market access.
In machine building, penetration tests are not an end in themselves. They are part of a traceable security and evidence strategy. If you want to clarify how tests fit into your product development and regulatory preparation, we are happy to talk in a no-obligation call.
