Automated XSS Scanning Techniques

Active scanning automates XSS detection across discovered application content. After spidering completes, initiate active scanning with XSS-focused policies. ZAP systematically injects payloads into every identified input vector, analyzing responses for successful injection. The scanner uses progressively complex payloads, starting with basic scripts and advancing to filter bypass techniques.

Understanding ZAP's payload progression helps interpret results. Initial payloads test for complete lack of filtering with standard tags like <script>, <img>, and <svg>. When these fail, ZAP attempts filter bypasses using encoding, case variations, and malformed tags. Advanced payloads exploit specific contexts like JavaScript strings, HTML attributes, or CSS contexts. Each successful payload provides information about filtering weaknesses.

Response analysis determines XSS vulnerability presence. ZAP looks for unmodified payload reflections indicating no filtering. Partial reflections suggest incomplete filtering that might still be exploitable. Context analysis determines if reflected content executes—payloads in HTML comments or textarea elements might reflect safely. ZAP's algorithms consider these contexts, reducing false positives while maintaining detection sensitivity.