PoC Code for Facebook Friend Profiler Gatherer

The code on this page iterates over Facebook profile IDs, employing the CSS History Hack to determine whether each profile has been visited by you. Much of this work is indebted to Jeremiah Grossman and Robert Hansen. This PoC stores NO information about you, but illustrates how easy it would be for a blackhat to do so.

An explanation of some of the JavaScript herein:

• It uses a setInterval call to keep the UI responsive with a callback time of 13ms. This seems to be enough, on my system, to leave the browser functional, while operating at maximum speed. Credits to this method to James Edwards.
• It employs mod 10 loop unrolling to optimize the repeated calls. Furthermore, the loop uses countdown, as opposed to countup as in all JS implementations this is faster. (Don't ask).
• The loop starts at 500800000 in the search for profile URLs. This is because I found that most Facebook profile registrations for my tests were within this numerical ordering.

A server-side lookup of usernames is performed by the following python cgi script:

#!/usr/bin/env python
# -*- coding: utf-8 -*-
import cgi
import cgitb; cgitb.enable()

print "Content-type: text/html"
print 
form = cgi.FieldStorage()
id = form.getfirst("id", "")

if id != "":
  from urllib import urlopen
  import re
  data = urlopen('http://www.facebook.com/profile.php?id=' + str(int(id))).read()
  p = re.compile('.*?([a-zA-Z\s]+) is on Facebook.*', re.MULTILINE)
  
  m = p.search(data)
  
  if m:
    print m.group(1)
  else:
    print id

The implications of the disclosure of this data is obvious. With as few as two hits it would be possible to begin intersecting public information to narrow down the likely identity of the visitor. It would also, obviously, be extremely easy for spammers to market their products with what appeared as customized messages: "Your Friend recommended this to you!" etc.

Current position: []

The boring stuff

NAME: Facebook friend list stealing PoC
AUTHOR: Martin Eve

BSD LICENSE:
Copyright (c) 2010, Martin Eve
All rights reserved.

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