How to test cybersecurity: Top mistakes when testing your online security

Many organisations have invested heavily in cybersecurity over the past few years. Firewalls, EDR, monitoring, SOC services, awareness training – the list goes on and often grows year by year. Yet breaches still happen, even in businesses that feel they’ve done everything right. One reason is surprisingly common: The organisation hasn’t actually tested cybersecurity in a way that reflects how attacks work in real life. 

At NetNordic, we often meet companies that have strong security ambitions and good tools in place, yet they still lack one thing: a clear, measurable answer to a simple question: What would actually happen if someone tried to break in today?

That’s where penetration testing comes in. Done properly, it gives a clear overview of something that’s hard to achieve through policies and dashboards alone. A real-world view of risk, impact, and priorities – and thereby also a way to fix them.

What it really means to test cybersecurity

Cybersecurity testing can mean many things. Vulnerability scans. Compliance audits. Configuration reviews. Tabletop exercises. All valuable in their own way. But penetration testing (often shortened to pentesting) is different.

A penetration test is a controlled simulation of a real cyberattack, carried out by ethical specialists. The point isn’t to create a long technical report. It’s to understand what an attacker could do if they targeted your organisation right now.

In other words, it connects technical weaknesses to business impact. And that’s what makes it so valuable. It not only points out theoretical weak spots – it finds every little creak an attacker might slip through. 

Compliance requirements are important. Regulations and frameworks have helped push security maturity forward, especially for organisations that provide critical services or deal with sensitive information. But it’s risky to assume that being compliant means being secure.

Compliance tells you whether you have the right controls and documentation in place. Penetration testing tells you whether those controls actually work when someone tries to bypass them. And that small difference matters.

In practice, many breaches happen in organisations that, on paper, should have been protected – because attackers look for loopholes outside of the regulations. They search for weaknesses that can be combined, misconfigurations that slipped through changes, and gaps between tools and teams.

Said in other words: If compliance is the baseline, penetration testing is the verification.

Vulnerability scanning plays an important role in cybersecurity. It helps you identify known vulnerabilities (such as CVEs), missing patches, outdated software, and misconfigurations.

But scanning isn’t the same as pentesting. While a scan can tell you what looks like a potential issue, a pentest can tell you whether the potential issue can actually be exploited – and, more importantly, what happens if it is? Both are useful, but they serve very different purposes. And if you want to truly test your cybersecurity, you need clarity on what each activity proves – and what it does not.

A penetration test is only as valuable as the scope behind it. Therefore, the first step should always be defining what matters most, such as:

• What systems are critical to your business?
• What would be most damaging to lose access to?
• Where is sensitive data processed or stored?
• Which services are essential for daily operations?
  

Without this alignment, testing can become either too shallow or too broad. And in both cases, the organisation ends up with findings that might be difficult to act on. At NetNordic, we often see scoping problems take one of these forms:

Testing “something” instead of what matters

Some organisations schedule a pentest because it feels like the right thing to do. But by doing this, the test often ends up targeting the easiest environment, not the most important one.

Underestimating hybrid IT environments

Even organisations that are cloud-first still rely on critical services: Identity and access management, endpoints, SaaS tools, integrations, and in many cases on-premises infrastructure. Cloud adoption changes the landscape, but it doesn’t remove risk – it shifts it.

Missing dependencies and third parties

Your security posture is not only defined by what you control internally. Vendors, suppliers, outsourced services, and custom-built systems often become blind spots. The more complex the ecosystem, the more important it is to include those dependencies in the testing strategy.

A strong scope is business-driven, and it might focus on:

• CRM systems and customer data
• HR platforms and identity access
• Systems supporting manufacturing and operational processes
• Email and office applications
• Critical infrastructure components (where relevant)
  

The goal isn’t to test everything at once. The goal is to test what matters most first. And, ideally, to keep testing to stay protected even through internal or external changes.

Traditional penetration testing is often performed once a year. Sometimes even less frequently. And honestly, that approach is understandable, as pentesting has historically been time-boxed, manual, and consultant-led. But it doesn’t align well with how modern IT environments evolve.

Today, most organisations change constantly. From minor to big developments, change can look like:

• New SaaS tools are introduced
• Cloud configurations are adjusted
• Users and privileges shift
• New suppliers are onboarded
• Systems are patched, upgraded, replaced, or integrated
  

At the same time, attackers operate continuously. They don’t wait for your annual test window, and they might even work for weeks or months to find a way to bypass your security measures.

It is important to remember, however, that a penetration test is a snapshot. It shows how things looked at that moment. The challenge is that the environment may look different a month later. That’s why more organisations are moving towards ongoing validation, where testing becomes part of security operations rather than a yearly milestone.

Attackers rarely rely on a single vulnerability. In fact, most successful attacks happen because small weaknesses combine:

• Misconfigurations
• Exposed services
• Weak or reused credentials
• Over-permissioned user accounts
• Gaps in monitoring coverage
• Insufficient segmentation
• Human error and social engineering
  

Penetration testing is valuable because it reflects this reality. It demonstrates what happens when multiple weaknesses can be chained together into an actual compromise.

Depending on the scope, a test can also include human-based attack methods such as phishing simulations or impersonation attempts – because in many cases, the quickest route in is still through people.

For management teams, this is an important shift in thinking: Cybersecurity is not only about technical controls. It’s also very much about people, processes, and the way the organisation responds when pressure is applied.

A common assumption is that having the right tools means the organisation is protected. Firewalls, EDR, SOC monitoring, identity controls and alerting are all essential. But tools can still leave gaps if they aren’t configured correctly, maintained over time, and validated against real attack scenarios.

In many organisations, blind spots might appear because:

• Complexity increases with size
• Visibility is fragmented across teams and suppliers
• Outsourced environments reduce direct control
• Custom-built systems don’t follow standard security patterns
• The supply chain becomes a real attack surface
  

Pentesting provides a practical way to validate whether your defences function as a complete system, not just as a collection of products.

What does a high-quality penetration test look like?

A good penetration test shouldn’t just deliver findings. It should deliver understanding and priorities. And most importantly, it should provide a clear image of where the weaknesses are and what threat these weaknesses can cause.

And finally – it should be collaborative. Security isn’t something you can outsource and forget. It works best when the organisation and the security partner work together as a team.

Manual penetration testing vs continuous validation: Why most organisations need both

Manual penetration testing remains essential. Human creativity, experience, and the ability to think like an attacker are hard to replicate. But manual testing also has limitations. It’s typically time-boxed, periodic, and difficult to repeat at high frequency. 

This is why many organisations combine manual pentesting with continuous validation approaches. While manual pentesting brings depth, creativity, and tailored investigation, continuous validation helps ensure security controls still work as environments change.

The most effective approach is often a hybrid model: Continuous assurance for day-to-day confidence, and periodic manual tests for deeper assessment, high-risk systems, and compliance needs.

Test cybersecurity to reduce uncertainty – not just to tick a box

Penetration testing isn’t about proving that an organisation is insecure. It’s about removing uncertainty.

In a threat landscape where attackers are persistent and environments constantly change, the ability to test cybersecurity continuously and realistically is becoming a core part of modern security leadership. Because in the end, confidence doesn’t come from having controls in place.

It comes from knowing they work.

Read more about our cybersecurity cases here.