JavaScript Security: Defending Against Prototype Pollution and Supply Chain Risks

As JavaScript applications grow in complexity, securing them requires looking deep into the language runtime and the external packages we rely on every day. Vulnerabilities like prototype pollution and compromised third-party packages can expose your entire codebase to severe exploits if left unchecked. This text-based course guides you through foundational security concepts to protect your applications from modern runtime and supply chain threats. You will learn to recognize insecure patterns in your code, understand how attackers exploit dynamic features, and implement robust defenses to keep your dependencies secure. What you'll learn: Understand the mechanics of prototype pollution and how to write defensive code to prevent it; Analyze the risks of dynamic expression evaluation and secure your application logic; Audit npm ecosystem modules and manage third-party dependencies securely; Implement modern supply chain security practices, including lockfile verification and package pinning; Practice identifying vulnerabilities through detailed, step-by-step code analysis exercises; Configure automated security scanning tools to detect vulnerable packages early in your workflow. You will start by exploring core JavaScript inheritance concepts to understand why prototype pollution occurs, before moving on to practical strategies for securing expressions and sanitizing inputs. Finally, you will learn how to navigate the npm ecosystem safely, establishing a secure development workflow from local code to external dependencies. This course is designed for web developers, software engineers, and security beginners who want to build a solid foundation in application security. No advanced security background is required, though a basic familiarity with JavaScript and npm is helpful. Start reading today to build safer, more resilient JavaScript applications.