Securing Web Apps Against Cross-Site Scripting (XSS) Attacks

Cross-Site Scripting (XSS) remains one of the most common and dangerous vulnerabilities threatening modern web applications. Understanding how malicious scripts are injected and executed is the first step toward building resilient, secure user interfaces. This written course guides you through the mechanics of XSS, helping you transition from writing vulnerable code to implementing robust, modern security controls. You will learn to think like an attacker to better defend your applications, ensuring user data and sessions remain protected. What you'll learn: 1. Understand the core mechanics of Stored, Reflected, and DOM-based XSS attacks. 2. Identify common entry points and vulnerable patterns in JavaScript applications. 3. Implement context-aware output encoding and input validation techniques. 4. Configure strong Content Security Policies (CSP) to block unauthorized script execution. 5. Leverage modern web framework protections and trusted sanitization libraries. 6. Practice secure coding habits to prevent token theft and session hijacking. You will start with fundamental security concepts and terminology before exploring real-world attack scenarios through written code walkthroughs. The course then transitions to practical defense strategies, detailing how to implement modern sanitization techniques and configure server headers to mitigate risks. This course is designed for beginner web developers, software engineers, and security enthusiasts who want to build a solid foundation in web application security. No prior security experience is required, though a basic understanding of HTML and JavaScript is helpful. Step into the world of web security and start writing safer code today.