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Before we get into cracking passwords with programs, I will explain a couple old-fashioned ways to obtain someone’s password.
• Social Engineering – Social engineering is when a hacker takes advantage of trusting human beings to get information from them. For example, if the hacker was trying to get the password for a co-workers computer, he (Even though I use “he”, hackers are of both genders, and I just chose to use “he” in these examples.) could call the co-worker pretending to be from the IT department. The conversation could be something like:
Bob- “Hello Suzy. My name is Bob and I’m from the IT department. We are currently attempting to install a new security update on your computer, but we can’t seem to connect to the user database and extract your user information. Would you mind helping me out and letting me know your password before my boss starts breathing down my neck? It’s one of those days, ya’ know?”
Suzy would probably feel bad for Bob and let him know her password without any hesitation. BAM! She got social engineered. Now the hacker can do whatever he pleases with her account.
• Shoulder surfing – Shoulder surfing is exactly what it sounds like. The hacker would simply attempt to look over your shoulder as you type in your password. The hacker may also watch weather you glance around your desk, looking for a written reminder or the written password itself.
• Guessing – If you use a weak password, a hacker could simple guess it by using the information he knows about you. Some examples of
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this are: date of birth, phone number, favorite pet, and other simple things like these.
Now that we have the simple low-tech password cracking techniques out of the way, let’s explore some high-tech techniques. Some of the programs I will use in my examples may be blocked by your anti-virus programs when you attempt to run them. Make sure you disable your anti-virus program when you decide to download and explore them.
There are different ways a hacker can go about cracking a password. Below I will explain and give an example of each way.

Dictionary Attacks

A dictionary attack is when a text file full of commonly used passwords, or a list of every word from the dictionary is used against a password database. Strong passwords usually aren’t vulnerable to this kind of attack. In the following example, I will use Brutus, a very common password cracker, to show a dictionary attack against an ftp server. Brutus is a Windows only program, but at the end of this chapter I will list a couple more password crackers, some of which are made for Mac, Windows, and Linux.

Before I get into the example, you must first know what an FTP server is. FTP stands for File Transfer Protocol. FTP is a simple way to exchange files over the internet. If a hacker got FTP access to my website, he could delete/upload anything he wants on my server. An FTP address looks similar to a website address except it uses the prefix ftp:// instead of http://. I set up an FTP server on my computer so I could demonstrate. You can get Brutus at http://www.hoobie.net/brutus/ .

1.  First the hacker would choose a target. In this case it’s my home computer and the IP address for your home computer is 127.0.0.1 .
2.  By going to ftp://127.0.0.1 I get a pop-up box asking for a username and password.

3. Next the hacker would launch a program similar to Brutus and attempt to crack the password.

4. In the target you put the IP address of the website and to the right select the appropriate option, which in this case is FTP.
5. The default port is 21 but some websites change this to make them a little more secure. If you find out that the port isn’t 21, you can find the right one by doing a port scan. We will get into this later in the book.
6. If you don’t know any of the usernames for the FTP server, then you will have to get a list of the most common usernames.
7. For a dictionary attack you will have to choose the pass mode Word List and browse and select the file containing your word list. You can get some good password lists at http://packetstormsecurity.org/Crackers/wordlists/ . Below are examples of what a username and password list might look like.

8. Once you hit Start the program will attempt to connect to the server and begin to try all the possible combinations from your lists.

9. If you’re lucky, eventually it’ll get the right Username:Password combination. As you can see below, it got the correct combination of username – admin and password – password.

10. A smarter hacker would use a proxy when using a program like this. What a proxy does is cloaks your IP address by sending your connection request through another computer before going to the target. This is a smart idea because as you will see in the image below, Brutus leaves a huge log of your presence on the target server.

11. In place of the IP address 127.0.0.1 would be the hackers IP address. Footprints like these get a hacker caught and into a lot of trouble with the law.