HTTP Parameter Pollution

["Luca.carettoni" <luca.carettoni@xxxxxxxxxxxx>]

Hi Folks,
              during OWASP AppSec 2009 we have presented a newly discovered 
input validation vulnerability called "HTTP Parameter Pollution" (HPP). 

Basically, it can be defined as the feasibility to override or add HTTP 
GET/POST parameters by injecting query string delimiters. 
During the last months, we have discovered several real world flaws in which 
HPP can be used to modify the application behaviors, access uncontrollable 
variables and even bypass input validation checkpoints and WAFs rules. 
Exploiting such HPP vulnerabilities, we have found several problems in some 
Google Search Appliance front-end scripts, Ask.com, Yahoo! Mail Classic and 
many other products.

If you enjoy the web security world, you are kindly invited to have a look at:  
 
http://www.owasp.org/images/b/ba/AppsecEU09_CarettoniDiPaola_v0.8.pdf

We're going to release additional materials in the next future, including a 
video of the Yahoo! attack vector. 
Stay tuned on http://blog.mindedsecurity.com and http://blog.nibblesec.org

Cheers,
Luca Carettoni and Stefano Di Paola