Testing for reflected XSS manually with Burp Suite - Port Swigger
Summary: PortSwigger's guide describes reflected XSS as occurring when an application receives data in an HTTP request and includes it in the immediate response without safe handling. It walks through manual testing in Burp Repeater: note where the input is reflected and in what context, enable auto-scroll on response changes, replace a canary string with a proof-of-concept such as <script>alert(1)</script>, and resend until the payload appears in the response.
Bottom line: The technique needs nothing more than a reflected parameter and a payload returned unencoded - the guide's own example reflects input inside an HTML <h1> element, so any application echoing request data into its responses is a candidate.
Read the original at PortSwigger Research ↗
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