Wiki: https://wiki.ubuntu.com/UbuntuWhiteHat

"A white hat hacker, also rendered as ethical hacker, is, in the realm of information technology, a person who is ethically opposed to the abuse of computer systems. Realization that the Internet now represents human voices from around the world has made the defense of its integrity an important pastime for many. A white hat generally focuses on securing IT systems, whereas a black hat (the opposite) would like to break into them." http://en.wikipedia.org/wiki/Ethical_hacker

The Ubuntu pentest team aims to take care of security problems in Ubuntu Services as Launchpad, REVU, Forums, website and other community systems.

Go to audit! :-)