HTML5 storage manipulation (reflected DOM-based)
Summary: PortSwigger describes reflected DOM-based HTML5 storage manipulation as a script storing attacker-controllable data in the browser's localStorage or sessionStorage, letting an attacker build a URL that makes another user's browser store that data. The storage itself is not a vulnerability, but if the application later reads the data back and processes it unsafely, it can deliver cross-site scripting and JavaScript injection; Burp Scanner flags it through dynamic and static analysis, and static analysis alone can produce false positives.
What's compelling: The flaw only becomes exploitable when client-side code reads stored data back and handles it unsafely, so a scanner finding without dynamic evidence may be a false positive that still points at code paths worth reviewing. PortSwigger's recommended fix is to keep all untrusted-origin data out of HTML5 storage, or enforce defenses in client-side code when functionality makes that unavoidable.
Read the original at PortSwigger Research ↗
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- Vulnerabilities & Patching
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