1.13.2010

Cracking Passwords with Teh Google

Have you ever googled yourself? You may have to sift through several pages of results about people with the same name that aren't you, but you would be surprised how easy it is to find a wealth of information about yourself by combinging information retrieved by your social networking profiles being indexed.

Have you ever tried your hand at cracking a password? Chances are if you have, you have downloaded a word list and may have eventually cracked a password (unless you happen to have a cluster of PS3's laying around to do all the processing for you)

Password cracking is a lost art that often requires a lot of patience. There are two primary methods of cracking passwords: online and offline. When you attempt to crack a password online, it is often via a 'brute-force' style attack and has to be throttled carefully to avoid immediate detection (although, any competent system admin will be able to spot an online BF from a mile away after 10 shots of tequila) Offline, is often much more difficult to accomplish, simply because in order to crack a password offline, you either need to obtain a password list, or at bare minimum the hash of the password that you are trying to crack.

All that aside, one of the most difficult and time consuming parts of cracking passwords is starting with the right wordlist. There are tons of really horrible wordlists spread all across the internet, and even a handful of good ones. I am fairly partial to the Common Passwords Dictionary and the extremely large dic-0294 when I am flying blind.

However, with the wealth of knowledge available on the internet about everyone you know from sites like facebook, myspace, linkedin, hi5, twitter, and the list goes on and on, there really is no need to fly blind anymore when cracking passwords.

Now before I go much further, let me warn you that this is a tedious process right now as I am not aware of any tools in the tubes that do this for you (although, such a tool probably would not be to difficult to build) Also I would like to note that as a security professional, the information that I am providing is as much a warning to people about how easy it is to get their password, as it is a informative post about something that has been sorely neglected in security presentations (that I have been privy too).

To keep this relatively brief while still getting the point across, the example I am providing below is purely fictional, and any similarity to actual people is completely unintentional.

Step 1: Recon
If you personally know your target, this step is pretty much already done - however, if you don't know the target, the first step is to find out some very basic information about them. This is all public domain information that is easy to gain through the use of search or social engineering. For the purpose of this example we will say that I am trying to crack the password of a coworker named Don Johnson.

Now I know very little about Don other than the company he works for (obviously) and the department that he is in. We will say that he is the director of Human Resources. Our fictitious company name will be Acme Inc.

So seeing as how I know about him only in his job, LinkedIn seems the obvious starting point for me. Now, LinkedIn is one of those funny psychological experiments that proves that people really don't care about their privacy, no matter what they say. Their profile may say that they are only interested in reconnecting with previous coworkers, but if a recruiter requests to be in their network, they will almost always click - if nothing else, for curiosity sake.

Google Search #1: site:linkedin.com "Don Johnson" +Acme +Denver

9 times out of 10, the Don Johnson we were looking for will be in the top 5 results returned from google. Once I have found his profile, it is quick and easy to get a free gmail account, create a fake recruiter profile on linkedin, and start adding a bunch of people, with Don among those being added. The reason for adding several people is that Don may be a little paranoid and if a recruiter with no network requests to be in his network, he may think twice about allowing him - however, if Don sees that this recruiter is acting like most every other recruiter on linkedin, and obsessively adding 10-20 people a day, well he will probably think nothing of it and allow the request. Once he is in your network you can view his full profile which will often include such information as all of his prior employers, education, blogs, etc. Generally, I will take a scrape of the entire profile (a scrape can be as simple as using File -> Save Page As in your browser) and use the information and picture from that profile to identify him on other networks.

Let us say that in the recon of my target I discovered a linkedin, facebook, myspace, and pandora account all linked to Don. I have scrapes of his profile pages from each network, along with an archive of comments and wall postings on friends profiles from the last 60 days.

Step 2: Assimilation of Information

This is where things really start to get interesting. You have a wealth of information now about your target. You know who he is dating, the names of all his pets (real and virtual), a list of his favorite musicians, movies, and books (invaluable), a collection of nicknames, his birtday, and much much more.

I specifically call out the fact that music, movies, and books are invaluable information to know about a target. Often, people will use a term or character name from their favorite stories as all or part of their password. So that being said, you can take Don's favorite songs look up the lyrics and start your wordlist. Next, look up a character list from his favorite books and movies, then lookup memorable quotes from those characters (imdb.com) and (wikipedia) are your friends here. Keep doing this with all the information you have until you have a comprehensive word list built specifically around the social profile of your target.

This is it, this is all you need to do. I have a relatively high (60-70%) success rate when building a custom word list using this method and if I were to take the time to build some tool that used the full power of the internet to build related information, I could almost guarantee a 90%+ success rate at using this method.

So the next time you are updating your profile on myspace or facebook, think about the password that you are using to login to that site and see if you can connect the dots between your password and any of the information on your profile. I would say that for most people, they will be able to make the connection fairly quickly and most of the time.

I purposefully described this process in a fairly abstract manner, as it is a very effective means of social engineering without having any direct contact with the target, and really, there are enough bad guys in the world already.

We rely on technology to keep our personal information secure and safe, yet the true dangers still lie in the information that we publicly disclose without a second thought. This is no different from the days of dumpster diving, only google is a much cleaner and organized dumpster.

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