H2HC São Paulo - Capture the Captcha

["Rodrigo Rubira Branco (BSDaemon)" <rodrigo () kernelhacking com>]

 We would like to thank to our sponsors for making this game possible: 
Bonsai for hosting the game and Tenable for providing the prize!

A Captcha is a type of challenge-response test used in computing to
ensure that the response is not generated by a computer. It is a
contrived acronym for "Completely Automated Public Turing test to tell
Computers and Humans Apart."

The process usually involves one computer asking a user to complete a
simple test (Captcha) which the computer is able to generate and grade.
Because other computers are unable to solve the Captcha, any user
entering a correct solution is presumed to be Human.

There are a lot of Captcha implementations out there, written in JSP,
PHP, ASP, .NET which are very poorly implemented and introduce serious
bugs in Web applications they are supposed to protect.

We developed 10 different Captcha implementations, each with its own
weakness, for participants to break using automation and hacking
techniques with the objective of bypassing the human verification process.

Teams (or a single participant) are scored on their success in breaking
the security behind every presented Captcha on the game.

This CTC contest is designed to serve as an educational exercise to give
participants experience in securing Web Applications from automated
attacks, as well as conducting and reacting to the sort of Captchas
found in the wild.

The participantes will need to register during the conference and the
winners will need to provide full information in order to receive the
major prize:  The Nessus Professional Edition from Tenable!