What is XSS Payload Detection?

Understanding XSS Payload Detection

XSS payload detection is the process of identifying malicious cross-site scripting code injected into a web application's inputs, requests, or responses so it can be blocked before it executes in a victim's browser. It targets the scripts attackers use to hijack sessions, steal credentials, or manipulate page content, and is a key defense in web application security.

Detection operates at several points. Input filtering and validation inspect incoming data for script-like patterns such as `` hoping it executes and exfiltrates session cookies. The application's WAF matches the payload against its XSS signatures and blocks the request, input validation rejects the unexpected markup, and as a final safeguard output encoding would render the string harmlessly as text. Together these layers ensure the script never runs in another user's browser.