Introduction:
This is a multi-part tutorial that will show you the tools of wireless attacks and penetration testing.

• A laptop or two. One laptop will act as the penetration tester and the other will be the victim. Of course if you do not have two laptops you can use a desktop with virtual machines, which is what we will be doing for these lessons.
• One Alfa wireless adapter. This is sort-of required because the Alfa adapter will support packet injection and sniffing out as well as work with Backtrack right out of the box.
  Alfa AWUS036H USB Wireless Long-Rang WiFi network Adapter with 5dBi Antenna
• A wireless router that we can use.
  D-Link DIR-601 Wireless-N 150 Router

• And finally, a connection to the internet.

Recommended Reading: BackTrack 5 Wireless Penetration Testing Beginner’s Guide
This book covers a lot of the topics you’ll find on this site. However, it goes into much more depth. It goes in easy to follow, simple, step by step lessons. Highly recommended for anyone starting out in wireless security/hacking.

Tutorial 1: Setting up your wireless card.
Plug in the wireless adapter into your laptop’s USB port.
Log in, open up the console and type: iwconfig.The iwconfig command lists all wireless interfaces on your machine. In my case, I have my Alfa One adapter connected as wlan0. Typing iwconfig wlan0 will display more information about your wlan0 interface. The mac address that is displayed should match up with the MAC address written on the back of your wireless adapter.
Now to put your wireless adapter into a monitor mode interface. To do this, simply type: airmon-ng start wlan0. The monitor interface will be named mon0.
Tutorial 2: Getting networking on BackTrack
By default, backtrack does not boot with working networking, this is to increase its stealth when penetration testing. The easiest way to get networking is using the WICD Network Manager. Click Applications -> Internet -> WICD Network Manager. Then select your wireless access point and connect.
If you receive and error message that says “Could not connect to wicd’s D-Bus interface. Check the wicd log for error message.” then simply enter the following commands into your terminal:
root@bt:~# dpkg-reconfigure wicd
root@bt:~# update-rc.d wicd defaults

Then restart your machine and the error should not occur anymore.

Packet Sniffing and Packet Injecting

WLAN Frames:

1. Management frames: Management frames are responsible for maintaining
   communication between the access points and wireless clients.
2. Control frames: Control frames are responsible for ensuring a proper exchange of
   data between the access point and wireless clients.
3. Data frames: Data frames carry the actual data sent on the wireless network. There
   are no sub-types for data frames.

Packet Sniffing with Wireshark