Bypassing Mozilla Port Blocking

To protect against the HTML Form Protocol Attack, which would allow the browser to send arbitrary data to most TCP ports, Mozilla restricted connections to several dozen ports. For example, click on http://jeremiahgrossman.blogspot.com:22/ See the screen shot:

I think it was RSnake who found this first, but the blocking mechanism seems to be only applied to the http protocol handler. Odd. Using the ftp protocol handler, we can bypass the block like so: ftp://jeremiahgrossman.blogspot.com:22/ If the port is up, it'll connect, if not, timeout.

I believe this technique could be used to improve JavaScript Port Scanning, where we’re currently only scanning horizontally for web servers (80/443). Instead we may be able to perform vertical port scans on the remaining ports and bypass the imposed restrictions. Perhaps also useful for the Browser Port Scanning without JavaScript technique.