Lesson overview · Free interview practice

Web Application Security

Web application security fundamentals: the OWASP Top 10 and how to defend against them.

Topics in the full lesson
  • Introduction to Web Security
  • OWASP Top Ten Vulnerabilities (2025 edition)
  • Secure Authentication Practices
  • Secure Authorization Practices
  • Input Validation and Output Encoding
  • Session Management
  • Secure Communication
  • Security Headers and CSP
  • Logging, Monitoring, and Incident Response
  • Best Practices
  • Exercises

Practice Problems

Work through a question before revealing its explanation. These questions and answers are free; Premium adds the full lesson walkthrough, examples and implementation detail.

Completion marks record your own progress, not an automatically checked result. The task type does not determine whether it is optional.

TheoryMedium

Preventing SQL Injection: Parameterized Queries + ORMs

Question

How does SQL injection work, and how do parameterized queries and ORMs prevent it?

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

TheoryMedium

Password Storage: Adaptive Hashing with Argon2, bcrypt, scrypt

Question

How should passwords be stored, and why are bcrypt/Argon2 the right choice vs SHA-256?

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

TheoryMedium

Principle of Least Privilege + Secure-by-Default Architecture

Question

What is the Principle of Least Privilege, and how does it pair with Defense in Depth and Secure by Default?

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

TheoryMedium

The OWASP Top 10 (2025): Categories and What Changed

Question

What is the OWASP Top 10, what are the 2025 categories, and how has the list evolved?

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

TheoryHard

Authentication & Session Patterns: JWT, OAuth2, Session Cookies

Question

What are the three canonical web authentication patterns, and when does each fit?

Take a moment to think about this before revealing the answer

Explain your reasoning or try an implementation before comparing answers.

Explore the full Web Application Security material

Premium includes the complete lessons and implementation references. Free practice questions remain available without a subscription.

All course tracks & premium content
From basics to advanced masterclasses
Built for JS/TS developers like you
Real-world tips & common pitfalls
Upgrade to Premium