Here’s a cool way to scan a site visitor’s network using just HTML and the user’s browser.
The concept of doing network scanning via JavaScript is hardly new and is quite easy for anyone with even cursory knowledge of JavaScript. However, the assumption was that as long as you browse the web with JavaScript disabled you are safe from hostile sites from scanning your network. Alas, this was not to be, in a very interesting post Jeremiah Grossman shows how can this be done with plain HTML using no JavaScript what so ever.