Conducting penetration tests is one of the best ways to assess your company’s security. But there's a catch: many think they’re doing it right… and they’re not. In fact, some mistakes are so common they’ve become part of the routine. And in cybersecurity, that’s an unnecessary risk. In this article, we’ll not only share the most common penetration testing mistakes but also how to avoid them.
What is Penetration Testing or Pentesting (and Why Should You Do It)?
If you haven’t read our article on what pentesting is, here’s a quick summary to get you up to speed: a penetration test is essentially simulating a hacker attack—but with good intentions. It’s about finding security gaps before someone with bad intentions does. Think of it as a controlled “assault” on your system to identify where the enemy could slip in.
And it’s not just about getting into servers. Networks, applications, devices, and of course, the human factor are all tested. Because yes, human error is still the easiest weakness to exploit. In other words: if you’re not conducting regular penetration tests, you’re playing with fire.
Why Is It So Important to Avoid Mistakes in Pentesting?
Because a poorly executed penetration test can give you a false sense of security. It’s like going to the doctor, getting a quick check-up, and being told “everything’s fine” without a proper examination.
From internal networks to web applications and employee behavior—everything matters. And the worst part is that a real hacker will check all of it without your permission or following any rules. That’s why a good penetration test must be realistic, well-planned, and thorough.
Read more: Web Pentesting: How to perform effective pentesting on your website?
7 Common Mistakes in Penetration Testing and How to Avoid Them
Mistake #1: Not Having a Clear Idea of What You Want to Test
This is the classic one. A penetration test begins with no clear objectives, as if it’s just about “seeing what happens.” And what happens? Nothing meaningful.
Before starting, you need to sit down, think, and define: What do we want to test? Which systems are we targeting? What kinds of attacks will we simulate? Without this, the pentest is like shooting arrows blindfolded.
The basics: define objectives, set the scope, and make sure everyone is on the same page. That’s where good pentesting starts.
Mistake #2: Half-Testing
Another classic: only testing what’s visible. The website, open ports, a server or two… and that’s it. But what about the rest?
Key components like APIs, internal databases, network-connected devices, or even physical access are often overlooked. Do you think an attacker will respect the “scope” of your test? Spoiler: they won’t.
That’s why tests must be thorough. It’s not about reviewing just the obvious—it’s about assessing what’s truly in use and vulnerable.
Mistake #3: Ignoring the Weakest Link—People
You’d be surprised how often successful attacks start with a simple phishing email. And yet, many penetration tests don’t include a single attempt at social engineering. Big mistake.
People are part of the system, and as such, they must be part of the test. Simulating fake emails, suspicious calls, or physical intrusion attempts is essential to understand how your team would react to a real threat. And no, it’s not about punishing anyone. It’s about learning, improving, and strengthening your cybersecurity culture.
Read more: Types of Pentesting: Which one is right for your business?
Mistake #4: Being Too “By the Book”
Another common mistake is following a rigid script. Scan ports, check known vulnerabilities, run a few exploits… and that’s it.
But real hackers don’t work like that. They improvise, mix techniques, and get creative. If your pentest doesn’t reflect that, you’re only doing half the job.
A good test needs a dose of chaos, experimentation, and thinking like a real attacker. Going off-script can uncover flaws that no scanner would ever detect.
Mistake #5: Not Considering the Real Business Impact
Not all vulnerabilities are equally dangerous. Some affect critical processes, and others… not so much. But if the final report treats everything as equally severe, teams won’t know where to start. This happens often: reports that don’t contextualize risk in business terms.
And that’s a problem. Because in the end, security isn’t just technical—it’s also about understanding which processes a breach affects and how serious the consequences could be. If a flaw could crash your sales system on Black Friday, it deserves top priority. Simple as that.
Mistake #6: Lack of Communication Between Teams
This is one of the quietest yet most harmful mistakes. The technical team goes one way, the security team another, vendors have no idea what’s happening… and in the end, no one is on the same page.
Security is everyone’s responsibility, and a penetration test should involve all key players from the start. Constant communication, interim reports, joint meetings—everything contributes to a result that’s useful and actionable.
Mistake #7: Delivering Reports No One Understands
What’s the point of conducting a great penetration test if the final report is a technical puzzle?
This happens more often than it should. Reports full of jargon, no prioritization, no clear actions, no business context. No one will act on that kind of information.
A good report should be clear, straightforward, and useful. Yes, it should include a technical section, but also an executive summary anyone can understand. And most importantly, it should include concrete steps to fix the issues found.
Read more: Phases of Pentesting: How to secure your systems step by step?
How to Do a Good Pentest?
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Work with external professionals like TecnetOne. There’s nothing like a fresh perspective to see what you might have overlooked.
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Simulate what a real attacker would do. Forget the checklist and think with an offensive mindset.
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Include everything, not just the obvious. APIs, employees, internal networks—everything matters.
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Do it regularly. Threats evolve every day, and your defenses should too.
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Act on what you discover. Finding vulnerabilities is useless if no one fixes them.
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Document and learn. Every test is a chance to grow and strengthen your organization.
Do Pentesting Right with TecnetOne (and Avoid Mistakes)
Penetration testing isn’t something you do just to check a box. It’s a powerful tool to truly improve your organization’s security.
But if done poorly, it can backfire—creating a false sense of security, overlooking critical areas, or simply leaving you clueless about what to do with the results.
The key is to avoid these mistakes, learn from each test, and treat security for what it is: a constant priority, not a once-a-year task.
At TecnetOne, we have a team of certified ethical hackers (CEH, OSCP, Hack the Box, eJPT) ready to help you strengthen your company’s security. We conduct penetration tests tailored to your environment, with actionable reports and real support—so you don’t just discover vulnerabilities, you actually fix them.
