Web Application Security Basics: The OWASP Top 10

Get an interview-ready overview of the most common web application vulnerability categories.

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What is it?

The OWASP Top 10 is an industry-standard, regularly updated list of the most critical web application security risks, maintained by the Open Web Application Security Project. It’s the reference point nearly every web security conversation — and interview — starts from. Common categories include Broken Access Control, Injection (like SQL injection), Cryptographic Failures, and Security Misconfiguration.

Why should I learn it?

Almost every entry-level web security or ethical hacking interview references OWASP directly. Being able to explain a few categories in your own words, with an example, is far stronger than reciting the list.

How it works

A web application accepts input or handles a request → if it fails to properly validate, authorise, or protect that interaction, it falls into one of the OWASP categories → testers systematically check for each category during a web application assessment → findings are reported with the specific OWASP category referenced, which gives the client immediate industry context on the type and severity of the issue.

Real-world example

A shopping site that lets a logged-in user change the user_id parameter in a URL to view another customer’s order history is a textbook Broken Access Control finding — the application checked that someone was logged in, but not that they were authorised to see that specific data.

Troubleshooting mindset

When assessing a web app, don’t just look for exotic bugs — systematically check the OWASP categories one by one; most real-world findings are common, well-documented categories, not novel discoveries.

Common mistake

Do not memorise the definition without connecting it to real engagement practice. Ask: what does this concept mean for what I’m allowed to actually do, and how would I prove I stayed within scope?

Quick recap

  • Understand the job of the phase or technique.
  • Know where it sits in the overall testing methodology.
  • Always tie it back to authorization and scope.
  • Connect the topic to the next phase of the engagement.

Interview connection

Explain the concept in simple words first, then connect it to authorization and real engagement practice. That is stronger than repeating a tool name.

References & Further Reading

  • AddySec original content — written for the Ethical Hacking track to build practical, interview-ready understanding.
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