-A Computer. (A Laptop works best)-A Wireless Card capable of packet injection.
-If your laptop wireless card can’t do packet injection you can purchase a wireless adapter such as the Netgear WG111 v2 for around $8-$12 on eBay.

-A Live installation of BackTrack either on a CD or USB stick.
-BackTrack 5 Can be found Here
-Create a Live USB Install Here

WEP is the predecessor of WPA and has been hacked for the past 5+ years yet people continue to use it. With the instructions below we can crack WEP in under 15 minutes.You can crack WEP from the command line but there is an easy GUI interface in backtrack which makes it a much less painful experience for those who are scared of command prompts.

1. Boot into BackTrack

2. Click on the Backtrack applications menu -> Backtrack -> Exploitation tools -> Wireless exploitation -> WLAN Exploitation -> gerix-wifi-cracker-ng (This will open up the GUI interface seen in the picture).

3. Go to the configuration menu and select the wireless interface wlan0
-Click on Enable/Disable Monitor Mode (this will put the wireless card into monitor mode).
-Select the newly created mon0 interface.

4. Now click on the WEP tab at the top of the window.
-Click on “Start sniffing and logging” and leave the terminal open.
-Once the wireless network you want to crack* shows up (it has to be WEP encryption of course) select the WEP Attacks (with clients). *note that the PWR has to be high enough to work so the closer you can get, the better.
-There you click on “Associate with AP using fake auth”, wait a few seconds and click on “ARP request replay”.

5. Once the Data number reaches over 10,000 you are ready to try (if the data is coming fast wait until 20 or 30,000 to be safe) and crack the key, but don’t close any windows yet.
-Go to the cracking tab and click on “Aircrack-ng – Decrypt WEP password” under Wep Cracking.

It will take a few seconds to minutes to crack the password and then you are good to go.

At least WPA and WPA2 are safe right? Wrong. WPA and WPA2 are both crackable but the time it takes to crack depends on the strength of their password.-Boot into BackTrack
-Open up Konsole which is a command line utility built into BackTrack. It is the Black Box in the Lower-Left Hand Corner (See Image).
We will now be entering the following commands into the command line noted by Bold as well as explanations as to what they do:

-The following commands stop the wireless interface so you can change your mac address, this is important because your mac address is a unique identifier so faking one is a good idea if you are accessing a network you don’t have permission to. (which by the way I wholly condemn)

1:
airmon-ng stop wlan0
ifconfig wlan0 down
macchanger –mac 00:11:22:33:44:55 wlan0
airmon-ng start wlan0

2:
-Now we will put the airodump-ng tool into monitor mode, this will allow us to see all of the wireless networks around us (See the first Picture).

airodump-ng mon0

Now choose the network you want to hack and take note of the BSSID, and the Channel it is one as well as the ESSID. The PWR has to be fairly high to be able to hack it, this is determined by how close you are to the wireless router. The closer you are, the better.

Once you have chosen the wireless network enter the following into the terminal:
This will write capture packets and put them into the “filename” file, we are trying to capture the handshake between the router and wireless connection which will give us the key we need to crack.

3:
airodump-ng mon0 –channel * –bssid **:**:**:**:**:** -w filename

The following step is optional but is highly recommended as it will speed up the process a great deal.

Once “WPA handshake: **:**:**:**:**:**” appears in the top right-hand corner we can move on. If you are having trouble getting the WPA handshake to occur then do step 4.

4:
aireplay-ng -0 1 -a **:**:**:**:**:** -c **:**:**:**:**:** mon0

What this step (4) does is it deauthorizes a wireless connection and trie to re-establish it so it will generate a new handshake to capture. This step ends once you have captured the handshake.

5:
aircrack-ng –w wordlist.lst -b **:**:**:**:**:** filename.cap

Step 5 is now trying to crack the password in “filename.cap” using a list of words, here called “wordlist.lst” you can download a good 200 million word dictionary here (128MB but unzipped is 800MB).

Your computer has to compute the hash value of every password in that list but a computer can go through those 200 million passwords in 6-12 hours.

6.

If the password isn’t found in the dictionary you can try and brute-force the password with this command: (Note this could take a very long time depending on their password strength).

/pentest/password/jtr/john –stdout –incremental:all | aircrack-ng -b **:**:**:**:**:** -w – filename.cap

Hopefully you gained some insight into how to not get your own wireless connection hacked:1. Use WPA2 (WPA2-AES) if available and by all means never use WEP.
2. Don’t base your password on a dictionary word. The next section focuses on passwords in general.
3. In your router settings you can usually hide your ESSID (the name of the wireless network) this will add a small layer of security.
4. In your router there is probably a mac-address filtering service where you can specify the mac addresses that are allowed to connect. This will make sure that only your approved devices can connect to your network. (obviously a problem though if you have a guest over and wants to connect to your Wifi).