Web Application Testing Matters — And Why OWASP Top 10

The Stakes Are High

Let’s face it: Web Application Testing is now essential. I’ve seen it firsthand. A single overlooked vulnerability can compromise an entire application. Web applications are everywhere—powering online banking, running e-commerce, and storing health records and personal data. Attackers are aware of this. According to Verizon’s Data Breach Investigations Report, web applications are involved in most confirmed data breaches. The threat is real, persistent, and increasing. So where do you begin? That’s the question I always hear. My answer is always the same: start with the OWASP Top 10.

Web Application Testing, what is it?

Web application testing is the process of finding security flaws before attackers do. It involves scanning, probing and analyzing a web app to uncover weaknesses. These weaknesses or vulnerabilities can be exploited to steal data, hijack accounts or crash systems. Testing can be manual, automated or both.

Common testing methods include:

• Penetration testing — simulated attacks by security professionals
• Static application security testing (SAST) — scanning source code for flaws
• Dynamic application security testing (DAST) — testing a live, running app
• Interactive application security testing (IAST) — combining SAST and DAST

The goal is simple. Find vulnerabilities first. Fix them before they’re exploited. Pretty Simple Right.

The Vulnerability Landscape Is Massive

Here’s something that surprises most people I work with. The National Vulnerability Database (NVD) tracks tens of thousands of new CVEs — Common Vulnerabilities and Exposures every year. In 2024 alone, researchers recorded more than 40,000 new CVEs. That’s an overwhelming number. No team can test for all of them. This is where the OWASP Top 10 becomes essential.

The OWASP Top 10 covers just 10 vulnerability categories. But those 10 categories account for roughly 60–70% of all web application vulnerabilities found in practice.

The math is powerful. A small, focused list covers the majority of real-world risk. Might want to start OWASP Top 10, I would.

What Is the OWASP Top 10?

OWASP stands for the Open Worldwide Application Security Project. (Google says it was renamed from ‘Web’ in 2023.) I was on the website and now they simply go by ‘OWASP.’

Anywho, it’s a nonprofit foundation dedicated to improving software security. The OWASP Top 10 is their flagship document. It lists the 10 most critical web application security risks, ranked by prevalence, detectability, and impact. It’s updated every few years to reflect current threats. The most recent version was published in 2021. Word on the street is that it might come out this year. (Opinion)

Here are the 10 categories from the 2021 list:

• A01 — Broken Access Control
• A02 — Cryptographic Failures
• A03 — Injection
• A04 — Insecure Design
• A05 — Security Misconfiguration
• A06 — Vulnerable and Outdated Components
• A07 — Identification and Authentication Failures
• A08 — Software and Data Integrity Failures
• A09 — Security Logging and Monitoring Failures
• A10 — Server-Side Request Forgery (SSRF)

Each category maps to dozens of specific CVEs and CWEs (Common Weakness Enumerations). That’s why 10 categories can cover so much ground.

Why I Recommend Starting With the OWASP Top 10

1. Data-Driven

The list isn’t based on opinion. It’s built from real-world breach data. OWASP analyzes millions of applications and thousands of CVEs to determine which risks are most common and most dangerous. That means testing against it isn’t guesswork. It’s prioritized, evidence-based security work.

2. Widely Accepted

The OWASP Top 10 is recognized by regulators, auditors and compliance frameworks worldwide. PCI DSS, HIPAA and SOC 2 all reference it directly or align with its guidance. When I present security findings to stakeholders, the OWASP Top 10 gives them context they already understand.

3. High-ROI Starting Point

Security resources are finite. You can’t test everything at once. Testing against the OWASP Top 10 gives you the highest return on investment. You address the most common, most impactful vulnerabilities first. Then you expand from there.

4. Covers Both Code and Configuration

Many vulnerability lists focus solely on code bugs. The OWASP Top 10 stands out because it includes misconfigurations, design flaws, outdated components, and logging failures. This provides a more comprehensive view of real-world risks.

How to Get Started With OWASP Top 10 Testing

Getting started doesn’t have to be complicated. Here’s the approach I use:

Understand Each Category

Read the OWASP Top 10 documentation at owasp.org. Each category includes a description, example attack scenarios and recommended prevention methods.

Map to Your Application

Not every risk applies equally to every app. Map each OWASP category to your specific application stack, architecture and data flows.

Use the Right Tools

Several free and commercial tools are built around the OWASP Top 10. OWASP ZAP is a popular free DAST tool. Burp Suite is a widely used professional option. There are many SAST Choices take your pick. I would recommend as manual as possible, but you can use AI pretty easily. If anyone can comment on this let me know.

Combine Automated and Manual Testing

Use Both Automated and Manual Testing. Get the best of both worlds. Automated tools find common issues fast. But they miss logic flaws and context-specific vulnerabilities. Manual testing fills those gaps.

Track and Remediate

Testing without remediation is pointless. Log every finding, prioritize by risk level, and track fixes to completion. This is challenging because the developer may resist, but you must stand firm and ensure it gets fixed.

Retest and Expand

Now, after you give the report and developers say they fixed and addressed the Top 10. Maybe expand your testing scope, add threat modeling, run a black-box pen test, and include lesser-known CWEs. Conduct red team exercises. The bottom line is to stay secure and continually test and retest.

The Bottom Line

Web application testing is no longer optional. It is a fundamental requirement for any organization that operates web-facing software. The OWASP Top 10 is the best place to begin. It is proven, practical, and data-driven. With ten categories, it covers the majority of real-world risks. I won’t say it covers everything, and it doesn’t. But it provides security teams with a clear, actionable starting point, and that’s exactly what most organizations need. Start with the OWASP Top 10. Security is a journey, not a destination. But every journey begins with a first step.

Want to start testing your web application against the OWASP Top 10? Download the free OWASP testing guide at owasp.org or reach out to our security team to build a testing plan today.