How to crack wi-fi with reaver

What you'll need?:

• Backtrack 5
• Computer with wi-fi and a DVD drive
• A nearby WPA-secured wi-fi network
• A little patience

Let's get crackin'

At this point you should have BackTrack burned to a DVD, and you should have your laptop handy.

• Step 1: Boot into BackTrack

To boot into BackTrack, just put the DVD in your drive and boot your machine from the disc. (Google around if you don't know anything about live CDs/DVDs and need help with this part.) During the boot process, BackTrack will prompt you to to choose the boot mode. Select "BackTrack Text - Default Boot Text Mode" and press Enter.

Eventually BackTrack will boot to a command line prompt. When you've reached the prompt, type startx and press Enter. BackTrack will boot into its graphical interface.

• Step 2:Install reaver

Reaver has been added to the bleeding edge version of BackTrack, but it's not yet incorporated with the live DVD, so as of this writing, you need to install Reaver before proceeding. (Eventually, Reaver will simply be incorporated with BackTrack by default.) To install Reaver, you'll first need to connect to a Wi-Fi network that you have the password to.

1. Click Applications > Internet > Wicd Network Manager
2. Select your network and click Connect, enter your password if necessary, click OK, and then click Connect a second time.

Now that you're online, let's install Reaver. Click the Terminal button in the menu bar (or click Applications > Accessories > Terminal). At the prompt, type:
apt-get update 

And then, after the update completes:

apt-get install reaver
If all went well, Reaver should now be installed. It may seem a little lame that you need to connect to a network to do this, but it will remain installed until you reboot your computer. At this point, go ahead and disconnect from the network by opening Wicd Network Manager again and clicking Disconnect. (You may not strictly need to do this. I did just because it felt like I was somehow cheating if I were already connected to a network.)

• Step 3: Gather Your Device Information, Prep Your Crackin'

 In order to use Reaver, you need to get your wireless card's interface name, the BSSID of the router you're attempting to crack (the BSSID is a unique series of letters and numbers that identifies a router), and you need to make sure your wireless card is in monitor mode. So let's do all that.
Find your wireless card: Inside Terminal, type:

iwconfig

Press Enter. You should see a wireless device in the subsequent list. Most likely, it'll be named wlan0, but if you have more than one wireless card, or a more unusual networking setup, it may be named something different.

Put your wireless card into monitor mode: Assuming your wireless card's interface name is wlan0, execute the following command to put your wireless card into monitor mode:

 airmon-ng start wlan0 

This command will output the name of monitor mode interface, which you'll also want to make note of. Most likely, it'll be mon0, like in the screenshot below. Make note of that.

Find the BSSID of the router you want to crack: Lastly, you need to get the unique identifier of the router you're attempting to crack so that you can point Reaver in the right direction. To do this, execute the following command:

airodump-ng wlan0 

You'll see a list of the wireless networks in range
When you see the network you want, press Ctrl+C to stop the list from refreshing, then copy that network's BSSID (it's the series of letters, numbers, and colons on the far left). The network should have WPA or WPA2 listed under the ENC column.
Now, with the BSSID and monitor interface name in hand, you've got everything you need to start up Reaver.

• Step 4: Crack a Network's WPA Password with Reaver

Now execute the following command in the Terminal, replacing bssid and moninterface with the BSSID and monitor interface and you copied down above:

reaver -i moninterface -b bssid -vv 

For example, if your monitor interface was mon0 like mine, and your BSSID was 8D:AE:9D:65:1F:B2 (a BSSID I just made up), your command would look like:

reaver -i mon0 -b 8D:AE:9D:65:1F:B2 -vv 

Press Enter, sit back, and let Reaver work its disturbing magic. Reaver will now try a series of PINs on the router in a brute force attack, one after another. This will take a while. In my successful test, Reaver took 2 hours and 30 minutes to crack the network and deliver me with the correct password. As mentioned above, the Reaver documentation says it can take between 4 and 10 hours, so it could take more or less time than I experienced, depending.

How Reaver Works

Now that you've seen how to use Reaver, let's take a quick overview of how Reaver works. The tool takes advantage of a vulnerability in something called Wi-Fi Protected Setup, or WPS. It's a feature that exists on many routers, intended to provide an easy setup process, and it's tied to a PIN that's hard-coded into the device. Reaver exploits a flaw in these PINs; the result is that, with enough time, it can reveal your WPA or WPA2 password.