Identifying Stored XSS Vulnerabilities

Stored XSS detection requires understanding application data flows. Identify features that store and display user input—comments, profiles, messages, or reviews. Use ZAP to inject unique identifiers into these features, then navigate to pages displaying stored content. The time delay between injection and execution complicates automated detection, making manual testing crucial.

Marker-based detection helps track stored payloads across complex applications. Inject payloads containing unique identifiers like <script>alert('ZAP-TEST-12345')</script>. Later, search responses for these markers to identify successful storage and execution points. This technique helps correlate injection points with execution contexts, essential for understanding stored XSS vulnerabilities.

Persistence verification ensures reported vulnerabilities are truly stored rather than temporarily cached. After identifying potential stored XSS, clear sessions and revisit affected pages. True stored XSS persists across sessions and affects other users. Cache-based reflections might appear stored but only affect the current session. This distinction impacts severity ratings and remediation approaches.