What Is Web Application Security

Web application security is protecting websites and web apps from attack. Because the web is the largest attack surface, it is where most security testing and most entry level jobs are.

In this guide
  1. Why web application security matters most
  2. The common vulnerabilities
  3. How testing works
  4. How to learn it

Why web application security matters most

Almost everything is a web application now. That makes the browser the front door to most breaches, and web application testing the largest single category of security work.

The common vulnerabilities

VulnerabilityWhat it does
InjectionTurns input into commands, like SQL injection
Broken access controlLets users reach data that is not theirs
XSSRuns attacker script in a victim's browser
SSRFMakes the server fetch attacker chosen URLs
Auth flawsWeak login, session and reset handling

The industry reference is the OWASP Top 10, explained in full in OWASP Top 10 explained.

How testing works

A tester maps the application, then probes every input and every access boundary by hand, using a proxy like Burp Suite to intercept and modify requests. See SQL injection and XSS explained for concrete examples.

TakeawayThe highest severity web findings, broken access control and business logic, are the ones no scanner catches. That is why manual skill still pays.

How to learn it

Learn how the web works, then exploit the OWASP Top 10 by hand on free labs. The structured path is the web application security course.

Learn to test web applications

Live, hands on, OWASP exploited not just read.

See the program

Related

ProgramWeb Application Security CourseGuideWhat Is API SecurityGuideWhat Is Penetration TestingSyllabusWeb Pentesting Syllabus

Frequently asked questions

What is web application security?

Protecting web apps from attack, and testing them to find weaknesses before attackers do.

What is the OWASP Top 10?

A ranked awareness list of the most critical web application security risks, used as a testing reference.

What tools test web application security?

Burp Suite primarily, with SQLmap and supporting tools. Manual testing matters more than any tool.

Is web security a good area to start?

Yes, it is the largest category of security work and where most entry level roles are.

How do I learn web application security?

Learn how the web works, then exploit the OWASP Top 10 by hand on labs, then take a structured program.