Added smb_spider.rb

SMB Spidering is a very useful technique I've been using on several internal pentests when I've obtained a set of valid credentials and would like to avoid poking through directories to find sensitive files. So for example, if I gain domain admin creds, and want to spider a number of workstations and/or shares, I can run smbspider (I also have a python version of this)  and quickly get a neat, recursive listing of every single file that exists on the remote share.

In numerous instances, I've discovered sensitive password documents and other files of interest. On a recent penetration test, one of the goals was to access information pertaining to the company's sensitive data including current and future projects, any customer data, etc. As opposed to poking through approximately 500 shares (C$ and NAS shares), I used smbspider and simply grepped through the results to find my treasure.