This Phenoelit tool called ObiWaN is written to carry out brute force security testing on Webservers.
The idea behind this is webservers with simple challenge-response authentication mechanism mostly have no switches to set up intruder lockout or delay timings for wrong passwords. In fact this is the point to start from. Every user with a HTTP connection to a host with basic authentication can try username-password combinations as long as he/she likes.
Like other programs for UNIX system passwords (crack) or NT passwords (l0phtcrack) ObiWaN uses wordlists and alternations of numeric or alpha-numeric characters as possible passwords. Since Webservers allow unlimited requests it is a question of time and bandwith to break in a server system.
The most interesting targets are web based administration frontends like Netscapes Server Administration. If you can break in, you are able to create accounts, stop the server and modify its content. Real fun.
You can read the full documentation here.
Various versions (including Windows, Linux and Solaris) of ObiWaN are available for download here: