CSP stands for Content Security Policy, and it is a web security feature that helps protect websites against certain types of attacks, especially cross-site scripting (XSS) and data injection attacks. CSP is a security protocol that web administrators can implement to control which types of content may be executed on their website. This helps prevent malicious code from running in the browser, which can protect both the user and the site from potential threats.
How does CSP work?
CSP works by the server sending a security policy to the browser as part of the HTTP header. This policy specifies which resources may be loaded and executed on the webpage. With the help of CSP you can, for example, restrict:
- Scripts: Only allow scripts from trusted sources, such as your own domain or specific third-party providers.
- Stylesheets: You can control where CSS styles may be loaded from.
- Images: Restrict loading of images to specific domains.
- Iframe content: Determines which sources can be embedded via iframes.
If a browser encounters content that does not comply with the specified policy, it will block this content, reducing the risk of attacks.
Why is CSP important?
CSP is important because it helps prevent some of the most common attacks on websites. In particular XSS attacks (cross-site scripting), where malicious code is injected into web pages, can be prevented if CSP is implemented correctly. XSS can be used by hackers to steal user data, bypass security protocols, or even take control of the entire website.
Benefits of CSP:
- Prevents malicious code execution: CSP limits the execution of scripts from unknown or unauthorized sources, which reduces the risk of XSS and other attacks.
- Protects user data: By blocking malicious code CSP protects the data that users enter on a website, such as passwords or credit card information.
- Improves trust: Websites that implement CSP signal to users that their security is taken seriously.
CSP is therefore a central part of modern web security and should be an integrated part of any web development strategy to protect both owners and visitors.