What is Web Application Security?

Most real-world attacks don't target an operating system or a network cable — they target the web application sitting on top of them: the login form, the search box, the file upload, the API endpoint. Anywhere a web app accepts input from a stranger on the internet and does something with it is a potential way in.

This subject goes deeper into the handful of vulnerability classes responsible for most real breaches — the ones briefly introduced in the OWASP Top 10 article in Cybersecurity Fundamentals — and, just as important, the specific fix for each one. Security isn't abstract once you've seen the actual line of code that causes the problem, and the line that fixes it.