A vulnerability scan is an automated check that identifies known vulnerabilities in your systems. A pen test (penetration test) goes a step further: an ethical hacker actually tries to exploit those vulnerabilities, just as a real attacker would. Both tests are valuable, but they serve different purposes and complement each other.
You want to have your corporate network tested, but are unsure between a vulnerability scan and a pen test. This makes sense, because the terms are often used interchangeably. Sometimes a company even pays for a pen test, but actually receives a vulnerability scan. In this article, we clearly explain the difference so you can make the right choice for your situation.
What is a vulnerability scan?
A vulnerability scan is an automated process in which specialized software vets your network, servers, workstations and applications for known vulnerabilities. The scanner compares your systems against a database of thousands of known security vulnerabilities (CVEs) and generates a report with the vulnerabilities found, sorted by severity.
Think of a vulnerability scan as a digital MOT inspection: it quickly and widely checks for known problems, such as outdated software, weak passwords, open ports or misconfigurations. The report tells you what might be wrong, but not whether an attacker could effectively exploit it in practice.
A vulnerability scan is typically completed within a few hours to a day, can be repeated weekly or monthly, and is relatively affordable. This makes it an excellent tool for maintaining continuous visibility into your security status.
Benefits of a vulnerability scan:
- Wide coverage: scans your entire IT environment in a short period of time
- Repeatable: suitable for weekly or monthly monitoring
- Affordable: significantly cheaper than a pen test
- Compliance: meets basic regulatory requirements such as NIS2 and ISO 27001
Limitations:
- Detects only known vulnerabilities from the database
- Cannot detect complex attack chains
- Sometimes generates false positives: reports that in practice do not pose a risk
- Do not test whether a vulnerability is actually exploitable
What is a pen test?
A pen test (penetration test) is a simulated cyber attack performed by an ethical hacker using the same techniques as a real attacker. The goal is not only to find vulnerabilities, but also to demonstrate what an attacker can actually accomplish with them. Can someone access your customer data through that vulnerability? Can a hacker move laterally through your network and take over your entire domain?
Where a vulnerability scan stops at identifying potential problems, a pentester actively looks for ways to combine and exploit those problems. A pentester also discovers vulnerabilities that an automated scanner misses: problems in business logic, insecure workflows, or creative attack paths through seemingly innocuous vulnerabilities.
A good analogy: a vulnerability scan is like an X-ray that detects bone fractures. A pen test is like an MRI that also reveals soft tissue, internal bleeding and more subtle problems. Both are useful, but for a complete picture you sometimes need the depth of an MRI.
A professional pen test typically takes one to three weeks, depending on the scope and complexity. The result is a detailed report with vulnerabilities found, a description of how they were exploited, a risk assessment and concrete recommendations to fix the problems.
Benefits of a pen test:
- Discovers vulnerabilities that scanners miss, such as flaws in business logic
- Shows actual impact: what can an attacker actually achieve?
- Combines individual weaknesses into realistic attack scenarios
- Delivers a report usable as evidence for audits, insurance and clients
Limitations:
- Higher investment than a vulnerability scan
- Snapshot: test the situation in one specific moment
- Narrower scope: a pentester does not test every system, but focuses on the most critical parts
- Requires planning and coordination with your IT team
Comparison chart: pen test vs vulnerability scan
| Criterion | Vulnerability scan | Pentest |
|---|---|---|
| Approach | Automated (software) | Manually by ethical hacker |
| Purpose | Identify known vulnerabilities | Exploit vulnerabilities and demonstrate impact |
| Profundity | Broad but superficial | Focused and profound |
| Lead time | A few hours to 1 day | 1 to 3 weeks |
| Frequency | Weekly to monthly | Annually or when major changes occur |
| False positives | Regular | Minimal (manual verification) |
| Implementation | Internal or external | External specialist (OSCP, CEH). |
| Report | List of vulnerabilities and scores | Detailed with exploits, impact and recommendations |
| Investment | From ~€500-€1,500 per scan | From ~€3,000 to €15,000+ |
| Suitable for | Continuous monitoring, basic control | In-depth validation, compliance, risk analysis |
When do you opt for a vulnerability scan?
A vulnerability scan is the right choice if you want to perform a comprehensive audit of your entire IT environment on a regular basis. Specifically, a vulnerability scan is appropriate when:
- You want continuous visibility into new vulnerabilities in your network
- Your organization has just started structural vulnerability management
- You must meet compliance requirements that require regular scans, such as the CyberFundamentals framework (CyFun)
- You have just implemented patches or updates and want to check that everything is sealed correctly
- You have a limited budget and still want insight into your security status
In practice, we see with Flemish SMEs that a monthly vulnerability scan is a good starting point. It gives your IT team a concrete work list and makes patch management measurable.
When do you opt for a pen test?
A pen test is appropriate when you want to validate the true resilience of your systems. Specifically, a pen test is the right choice when:
- You want to know if an attacker can actually penetrate your systems
- Your organization puts a new system, application or network into production
- You are preparing for a cybersecurity audit or certification (ISO 27001, NIS2, SOC 2)
- A customer or insurer demands an external pen test report
- You want to understand what attack paths a hacker might follow within your network
- Your IT infrastructure has changed dramatically: new VPN, migration to the cloud, merger with another company
With the NIS2 compliance deadline of April 18, 2026 looming, we are seeing more and more Belgian companies having a pen test performed as part of their compliance assessment. The CCB’ s CyberFundamentals framework requires organizations to regularly validate their security measures, and a pen test is a strong means of proof.
The ideal combination: scan and pen test
The most effective approach is not to choose between a vulnerability scan and a pen test, but to combine both. In practice, that looks like this:
Ongoing: run a vulnerability scan monthly (or more often) to monitor your security status and quickly identify new vulnerabilities. This gives your IT team an up-to-date work list and makes patch management measurable.
Periodically: have a professional pentest performed annually by a specialized company to validate the true resilience of your critical systems. Schedule an additional pen test whenever you make major changes to your infrastructure.
For incidents: after a security incident, a combination of the two makes sense. A vulnerability scan shows whether there are still open vulnerabilities, while a pen test validates whether the measures taken are effective.
This layered approach is exactly what regulations such as NIS2 and frameworks such as CyFun expect from organizations: not one test a year to tick off, but a structural and ongoing process of vulnerability management and validation.
What should you consider when choosing a partner?
Whether you commission a vulnerability scan or a pen test, the quality of the partner determines the value of the result. When making your choice, consider the following:
Team certifications.
Look for recognized certifications such as OSCP (Offensive Security Certified Professional), CISSP, CEH or CISM. These guarantee that testers have proven expertise.
Transparency about the approach.
A reliable partner will explain in advance the methodology being followed (e.g., PTES or OWASP) and the scope of the test. Be alert if a vendor offers a “pen test” at a conspicuously low price: you are likely to get a vulnerability scan with a different label.
Reporting in human language.
A good report contains not only technical details for your IT team, but also a clear summary for management. This is essential if you want to use the report towards your management, an insurer or an auditor.
Belgian context.
A partner who knows the Flemish market, understands the specific regulatory context (NIS2, CyFun, VLAIO grants) and can advise on how your test results fit into the broader compliance process.
Did you know that through the VLAIO SME portfolio you can receive up to 45% subsidy on cybersecurity advice, including pen tests and vulnerability assessments? That makes professional security testing affordable even for smaller companies.
Conclusion
A vulnerability scan and a pen test are not competitors, but complementary tools in your security strategy. The vulnerability scan offers breadth and regularity; the pen test offers depth and realism. Together, they give you a complete picture of your security status.
Unsure which approach is best for your situation? Book a no-obligation consultation and our experts will help you make the right choice, tailored to your IT environment, budget and compliance obligations.
FREQUENTLY ASKED QUESTIONS
What is the difference between a pen test and a vulnerability scan?
A vulnerability scan is an automated check that identifies known vulnerabilities in your systems. A pen test goes further: an ethical hacker actually tries to exploit those vulnerabilities to show what impact an attack could have.
Do I need a pen test for NIS2 compliance?
NIS2 requires organizations to regularly validate their security measures. A pen test is a strong means of proof for this purpose, especially in conformity assessment through CyFun or ISO 27001. Essential entities must submit their first assessment by April 18, 2026.
How much does a vulnerability scan cost in Belgium?
A professional vulnerability scan typically costs between €500 and €1,500 per execution, depending on the scope. Automated tools for continuous scanning are available on a subscription basis. Up to 45% subsidy is possible through the VLAIO SME portfolio.
How much does a pen test cost in Belgium?
A professional pen test typically starts from €3,000 for a limited scope. Complex environments with multiple applications and network segments cost €10,000 to €15,000 or more. The investment depends on the type of pen test, the scope and the desired depth.
How often should I have a vulnerability scan performed?
For most organizations, a monthly vulnerability scan is a good frequency. After major changes to your infrastructure (new servers, software updates, migrations), an additional scan is recommended. Regulations such as NIS2 and PCI DSS may dictate specific frequencies.
Can a vulnerability scan replace a pen test?
No. A vulnerability scan detects known vulnerabilities but cannot show whether those vulnerabilities are actually exploitable. A scanner also misses complex attack paths and problems in business logic. For a complete risk assessment, you need both.
