http-parameter-pollution

HTTP parameter pollution exploits inconsistent parsing of duplicate query keys across security gateways and application layers, allowing a malicious value to bypass WAF filtering while the backend processes the attack payload. It maps first, last, and join behaviors to pinpoint divergent interpretations.

HTTP parameter pollution testing identifies when duplicate HTTP parameter names are parsed differently across a CDN/WAF, reverse proxy, and application framework, leading to security bypasses or logic flaws. It confirms first, last, join, or array-merge behavior per hop.

Send authorized duplicate-parameter requests like id=1&id=2 and compare responses to determine which layer treats the first versus last value as authoritative. This structured methodology drives practical cases like SSRF via conflicting URL validators and CSRF token confusion.

Yes, HTTP parameter pollution satisfies requirements for end-to-end request path modeling by fingerprinting parsing behavior across proxies and frameworks. It generates scenario-ready duplicate-key payloads to confirm where decoding disagreements occur across the delivery chain.

Testing duplicate HTTP keys for security bypasses is limited to authorized assessments where WAFs, routing, or framework decoding can disagree. It requires comparing responses across hops, so consistent parsing across all layers will yield no exploitable parameter pollution behavior.