Understand common web vulnerabilities and learn the best practices to protect your application and users.
Web security is a critical responsibility for every developer. An insecure application can lead to data breaches, loss of user trust, and legal consequences. This topic introduces fundamental security concepts. We'll cover major vulnerabilities like Cross-Site Scripting (XSS), where an attacker injects malicious scripts into a website viewed by other users, and Cross-Site Request Forgery (CSRF), which tricks a user into performing an unintended action. You'll learn about SQL Injection, an attack that manipulates database queries. The core of prevention lies in a defense-in-depth strategy: always validate and sanitize user input, use prepared statements for database queries, and properly encode output to prevent it from being interpreted as code. We will also discuss the importance of using HTTPS to encrypt data in transit, implementing secure authentication and authorization, and using security-focused HTTP headers to instruct browsers on how to behave safely. Tools like Helmet for Node.js can help set many of these headers automatically.