"The BackBox team is proud to announce the release 2.05 of BackBox Linux. The new release include features such as Ubuntu 11.04, Linux Kernel 2.6.38 and Xfce 4.8.0. The ISO images (32bit & 64bit)"

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http://www.backbox.org/downloads

BackBox is a GNU/Linux distribution based on Ubuntu. It has been developed to perform penetration tests and security assessments. Designed to be fast, easy to use and provide a minimal yet complete desktop environment, thanks to its own software repositories, always being updated to the latest stable version of the most used and best known ethical hacking tools.