WPA/WPA2 Bruteforcing and Hacking Tool: Reaver

Reaver is a WPA/WPA2 Bruteforcing and hacking Tool. The tool takes advantage of a vulnerability, 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

 In this tutorial we will explain How To Hack a Secure Wifi Network With Reaver??

First Of all You Must Have Some of the Prerequisites already Installed:

1. You must be running Backtrack Linux.
2. You must have a wireless card capable of raw injection.
3. You must put your wireless card into monitor mode. This is most easily done using airmon-ng from the aircrack-ng tool suite. 

Now, How To 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.

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

(Note: If  airodump-ng wlan0 doesn't work for you, you may want to try the monitor interface instead e.g.,        airodump-ng mon0.)

You'll see a list of the wireless networks in range—it'll look something like the screenshot below:

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. (If it's WEP, use our previous guide to cracking WEP passwords.)

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 moninterfacewith 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 was8D: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. When Reaver's cracking has completed, it'll look like this:

A few important factors to consider: 

Reaver worked exactly as advertised in my test, but it won't necessarily work on all routers (see more below). Also, the router you're cracking needs to have a relatively strong signal, so if you're hardly in range of a router, you'll likely experience problems, and Reaver may not work. Throughout the process, Reaver would sometimes experience a timeout, sometimes get locked in a loop trying the same PIN repeatedly, and so on. I just let it keep on running, and kept it close to the router, and eventually it worked its way through.

Also of note, you can also pause your progress at any time by pressing Ctrl+C while Reaver is running. This will quit the process, but Reaver will save any progress so that next time you run the command, you can pick up where you left off-as long as you don't shut down your computer (which, if you're running off a live DVD, will reset everything).

How to Protect Yourself Against Reaver Attacks

Since the vulnerability lies in the implementation of WPS, your network should be safe if you can simply turn off WPS (or, even better, if your router doesn't support it in the first place). Unfortunately, as Gallagher points out as Ars, even with WPS manually turned off through his router's settings, Reaver was still able to crack his password.