For example, a blog site might allow comments to be posted containing some limited HTML markup. Web developers would often use location.hash and pass it to the selector which would cause XSS as jQuery would render the HTML. With javascript: What is the best way to block scripting without block html markups (,
, etc.)? However, you should make sure that all possible injection points of your application have been analyzed and correctly fixed. You can do this by adding the 'unsafe-inline' source to the allowed source list, as in the following example: Of course, this approach enables your search feature but nullifies the benefit brought by 'self'. Also there are 3 Then, go to the Applications section of the Auth0 Dashboard and click on "Create Application". Parsing HTML input is difficult, if not impossible. It sends the result to the user's browser in the HTTP response. Why doesnt SpaceX sell Raptor engines commercially? For example: If a user supplies a value that is expected to be an email address, validate that the only contains the expected characters. If your user doesn't submit anything to your server you don't even need the above. Thanks for contributing an answer to Stack Overflow! Then navigate to the vulnerable website and add a new review on the movie. There is a Node.js project that sanitizes data and there is an OWASP library for JavaScript that handles sanitization to prevent XSS. If that is not possible then you can use hash- or nonce-based policy to allow scripts on different domains. Use a trusted and verified library to escape HTML inputs. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. If you include this code in a WordPress plugin, publish it and your plugin becomes popular, you can have no doubt that a security analyst will at some point contact you reporting this vulnerability. See how our software enables the world to secure the web. After submitting this string, you will get the following result in the page of the vulnerable website: At the bottom of the page, you find an empty comment. Follow these steps: Generate HTML safely using a templating engine, or use a static JavaScript frontend to avoid HTML generation altogether. XSS is an attack technique that injects malicious code into vulnerable web applications. At a basic level XSS works by tricking your application into inserting a