Top 10 winner

HTTP Parameter Pollution (HPP)

Minded Security Blog: Http Parameter Pollution a new web attack category (not just a new buzzword :p)

Stefano Di Paola · blog.mindedsecurity.com

Announces the AppSec EU 2009 talk naming HTTP Parameter Pollution. Injecting query string delimiters lets an attacker add or override parameters a server or client later re-parses, so hardcoded values can be replaced, application behaviour altered and input validation or WAF rules bypassed. Reported against Google Search Appliance scripts, Ask.com and Yahoo Mail Classic.

Record

Document

Minded Security Blog: Http Parameter Pollution a new web attack category (not just a new buzzword :p)

Researcher

Stefano Di Paola

Published by

blog.mindedsecurity.com

Topic

HTTP

In the archive

• Ranked #2 in the 2009 Top 10 Web Hacking Techniques

Related sources

• HTTP Parameter Pollution Whitepaper
• HTTP Parameter Pollution Slides

Tags

• http
• parser-differential
• injection
• waf-bypass
• filter-bypass
• url-parsing
• owasp-a03-2021
• owasp-a05-2021

This page is the archive's own catalogue record. The research is the work of Stefano Di Paola, first published at the original source. Preserved copies are kept so the citation survives its host; this one was last captured on 10 August 2026.