Spring Content Security Policy Guide: What It Is and How to Enable It

The Content Security Policy (CSP) is a crucial security standard designed to protect web applications from content injection attacks such as cross-site scripting (XSS) and clickjacking. It achieves this by specifying allowed content types and data sources, thereby preventing malicious code from being executed. In the context of Spring web applications, CSP can be implemented by configuring HTTP headers through the Spring Boot framework, using either XML or Java configurations. This involves adding dependencies like spring-boot-starter-security and spring-security-web to manage CSP headers, ensuring resources are only loaded from trusted origins. The implementation of CSP enhances the browser's ability to block unauthorized scripts, providing an additional layer of security against XSS attacks. The text also discusses the same-origin policy and how CSP complements it by enforcing a whitelist of trusted content sources. The article was authored by Tarun Telang, a seasoned software engineering leader with expertise in Java, web, mobile, and cloud technologies.