Introduction
If you followed my last tutorial on WPA cracking then you no doubt noticed how long it took to actually crack the password (if you cracked it at all). Well, there are a lucky few of you out there who can greatly increase that process with something called CUDA.
What is cuda?
CUDA is a parallel processor that comes on a select number of NVIDIA video cards. If you’re interested, you can read more about it here.
So What?
Parallel processing = super computer. So, turns out, you have a little super computing processor in desktop / laptop that will increase your cracking speed by up to 15 times!
Do I have CUDA?
If your video card is on this list, then yes you do. If not, sorry, you’re out of luck! You could use a service like WPACracker.com to speed up your cracking process, but it will cost you.
The Steps
Get backtrack & Snag a wpa capture
Grab your copy of BackTrack Linux.
and
Follow my WPA Cracking Guide up to the part right before we start cracking the password.
Get cuda working
Close X Windows
Click the dragon icon in the bottom right-hand corner and select “log out”.
Turn on networking
The easiest way to do this will be plugging your ethernet connection into a router and running:
root@bt:~#/etc/init.d/networking start
This should scan your networking interfaces and obtain an IP address. If you would like to make sure that you have an internet connection, run the ping command:
root@bt:~#ping -c 4 www.google.com
Update APT sources
To make sure we have the most recent list of files, let’s update our file list from the Backtrack repository:
root@bt:~# apt-get update
Install the NVIDIA Drivers
Make sure you’re connected to the internet, then open a terminal window and type:
root@bt:~# apt-get install nvidia-driver
Get CUDA
Now that Backtrack knows we have an Nvidia card, let’s install the tools we need to use CUDA:
root@bt:~# apt-get install cuda-sdk cpyrit-cuda
Test Pyrit
To check and see if Pyrit recognizes your NVIDIA card, type the following at the prompt:
root@bt:~# pyrit list_cores
If your results look like mine, congratulations, you’re almost there!
Get Cracking
Crack with cowpatty
Now we’re golden, after getting your wordlist together, type the following at the prompt to start cracking:
root@bt:~# pyrit -e (essid) -i (wordlist) -o - passthrough | cowpatty -d - -s (essid) -r (capfile)
and mine:
root@bt:~# pyrit -e TEST -i wpamangled.lst -o - passthrough |cowpatty -d - -s TEST -r TEST.cap
Cracked!
As you can see, cracking with CUDA is much faster than cracking regularly.
Here’s a screenshot comparison of the same capture file cracked with the same wordlist, but with and without CUDA.
With Aircrack-ng, but without CUDA:
With Pyrit, Cowpatty, and CUDA:
As you can see, using CUDA is well worth it. On my laptop, however, the Nvidia card is much slower than that of a desktop.
Closing
While this tutorial should work very well for anyone with a CUDA enabled computer, I encourage you to read the following resources if you have any questions pertaining to how CUDA works or what other programs you could possible use CUDA with.
