BackTrack Linux: WEP Cracking Tutorial - Command Line

So last post I told you about some of the main stream distros of Linux.  This week I am going to give you some information on a very special version of Linux.  I present to you one of the finest distros for the purpose of penetration testing, BackTrack Linux.  No you perverts it isn't a distro for making porno...it is a distro made to hack networks. In the right hands it can be used to test a network for legit purposes...in the wrong hands (the foolish hands) it could be used to fuck yourself.  Like feds knock on your door fucked.  Don't hack kiddies.  Just sayin.  Without further adieu.... How to crack a wep from the command line. :D

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*     How to Crack a Wi-Fi Network's WEP Password with BackTrack     *
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To crack WEP, you'll need to launch Konsole, BackTrack's built-in command 
line.  It's right there on the taskbar in the lower left corner, second 
button to the right. Now, the commands.

First run the following to get a list of your network interfaces:

    airmon-ng

The only one I've got there is labeled ra0. Yours may be different; take 
note of the label and write it down. From here on in, substitute it in 
everywhere a command includes (interface).

Now, run the following four commands. See the output that I got for them 
in the screenshot below.

    airmon-ng stop (interface)
    ifconfig (interface) down
    macchanger --mac 00:11:22:33:44:55 (interface)
    airmon-ng start (interface)

How to Crack a Wi-Fi Network's WEP Password with BackTrack If you don't 
get the same results from these commands as pictured here, most likely 
your network adapter won't work with this particular crack. If you do, 
you've successfully "faked" a new MAC address on your network interface, 
00:11:22:33:44:55.

Now it's time to pick your network. Run:

    airodump-ng (interface)

To see a list of wireless networks around you. When you see the one you 
want, hit Ctrl+C to stop the list. Highlight the row pertaining to the 
network of interest, and take note of two things: its BSSID and its 
channel (in the column labeled CH), as pictured below. Obviously the 
network you want to crack should have WEP encryption (in the ENC) column, 
not WPA or anything else.

How to Crack a Wi-Fi Network's WEP Password with BackTrack Like I said, 
hit Ctrl+C to stop this listing. (I had to do this once or twice to find 
the network I was looking for.) Once you've got it, highlight the BSSID 
and copy it to your clipboard for reuse in the upcoming commands.

Now we're going to watch what's going on with that network you chose and 
capture that information to a file. Run:

    airodump-ng -c (channel) -w (file name) --bssid (bssid) (interface)

Where (channel) is your network's channel, and (bssid) is the BSSID you 
just copied to clipboard. You can use the Shift+Insert key combination 
to paste it into the command. Enter anything descriptive for (file name). 
I chose "yoyo," which is the network's name I'm cracking.

How to Crack a Wi-Fi Network's WEP Password with BackTrack

You'll get output like what's in the window in the background pictured 
below. Leave that one be. Open a new Konsole window in the foreground, 
and enter this command:

    aireplay-ng -1 0 -a (bssid) -h 00:11:22:33:44:55 -e (essid) (interface)

Here the ESSID is the access point's SSID name, which in my case is yoyo. 
What you want to get after this command is the reassuring "Association 
successful" message with that smiley face.

How to Crack a Wi-Fi Network's WEP Password with BackTrack

You're almost there. Now it's time for:

    aireplay-ng -3 -b (bssid) -h 00:11:22:33:44:55 (interface)

Here we're creating router traffic to capture more throughput faster to 
speed up our crack. After a few minutes, that front window will start 
going crazy with read/write packets. (Also, I was unable to surf the web 
with the yoyo network on a separate computer while this was going on.) 
Here's the part where you might have to grab yourself a cup of coffee or 
take a walk. Basically you want to wait until enough data has been 
collected to run your crack. Watch the number in the "#Data" column--you 
want it to go above 10,000. (Pictured below it's only at 854.)

Depending on the power of your network (mine is inexplicably low at -32 
in that screenshot, even though the yoyo AP was in the same room as my 
adapter), this process could take some time. Wait until that #Data goes 
over 10k, though--because the crack won't work if it doesn't. In fact, 
you may need more than 10k, though that seems to be a working threshold 
for many.

How to Crack a Wi-Fi Network's WEP Password with BackTrack

Once you've collected enough data, it's the moment of truth. Launch a third 
Konsole window and run the following to crack that data you've collected:

    aircrack-ng -b (bssid) (file name-01.cap)

Here the filename should be whatever you entered above for (file name). 
You can browse to your Home directory to see it; it's the one with .cap 
as the extension.

If you didn't get enough data, aircrack will fail and tell you to try again 
with more. If it succeeds, it will look like this:

How to Crack a Wi-Fi Network's WEP Password with BackTrack The WEP key 
appears next to "KEY FOUND." Drop the colons and enter it to log onto the  

network. 


Shout out to Andy for this one.