How to Hack Wi-Fi: Cracking WPA2-PSK Passwords with Cowpatty

How to Hack Wi-Fi: Cracking WPA2-PSK 

Passwords with Cowpatty

I want to demonstrate another excellent piece of hacking software for cracking WPA2-PSK 

passwords. A few months ago, we cracked WPA2 using aircrack-ng. In this tutorial, we'll 

use a piece of software developed by wireless security researcher Joshua Wright called 

cowpatty (often stylized as coWPAtty). This app simplifies and speeds up the 

dictionary/hybrid attack against WPA2 passwords, so let's get to it!

Step 1: Find the Cowpatty

Cowpatty is one of the hundreds of pieces of software that are included in the BackTrack 

suite of software. For some reason, it was not placed in the /pentest/wireless directory, but 

instead was left in the /usr/local/bin directory, so let's navigate there.

[code]

cd /usr/local/bin

Because cowpatty is in the /usr/local/bin directory and this directory should be in your 

PATH, we should be able to run it from any directory in BackTrack.

Step 2: Find the Cowpatty Help Screen

To get a brief rundown of the cowpatty options, simply type:



[code]

cowpatty

BackTrack will provide you a brief help screen. Take a note that cowpatty requires all of the 

following.

- a word list

- a file where the password hash has been captured

- the SSID of the target AP

Step 3: Place the Wireless Adapter in Monitor Mode

Just as in cracking with aircrack-ng, we need to put the wireless adapter into monitor mode.

[code]

airmon-ng start wlan0

Step 4: Start a Capture File

Next, we need to start a capture file where the hashed password will be stored when we 

capture the 4-way handshake.

[code]

airodump-ng --bssid 00:25:9C:97:4F:48 -c 9 -w cowpatty mon0

This will start a dump on the selected AP (00:25:9C:97:4F:48), on the selected channel (-c 

9) and save the the hash in a file named cowcrack.

Step 5: Capture the Handshake

Now when someone connects to the AP, we'll capture the hash and airdump-ng will show 

us it has been captured in the upper right-hand corner.

Step 6: Run the Cowpatty

Now that we have the hash of the password, we can use it with cowpatty and our wordlist 

to crack the hash.

[code]

cowpatty -f /pentest/passwords/wordlists/darkc0de.lst -r /root/cowcrack-01.cap -s Mandela2

As you can see in the picture, cowpatty is generating a hash of every word on our wordlist 

with the SSID as a seed and comparing it to the captured hash. When the hashes match, it 

dsplays the password of the AP.

Step 7: Make Your Own Hash

Although running cowpatty can be rather simple, it can also be very slow. The password 

hash is hashed with SHA1 with a seed of the SSID. This means that the same password on 

different SSIDs will generate different hashes. This prevents us from simply using a 

rainbow 

table against all APs. Cowpatty must take the password list you provide and compute the 

hash with the SSID for each word. This is very CPU intensive and slow.

Cowpatty now supports using a pre-computed hash file rather than a plain-text word file, 

making the cracking of the WPA2-PSK password 1000x faster! Pre-computed hash files are 

available from the Church of WiFi, and these pre-computed hash files are generated using 

172,000 dictionary file and the 1,000 most popular SSIDs. As useful as this is, if your SSID 

is not in that 1,000, the hash list really doesn't help us.

In that case, we need to generate our own hashes for our target SSID. We can do this by 

using an application called genpmk. We can generate our hash file for the "darkcode" 

wordlist for the SSID "Mandela2" by typing:

[code]

genpmk -f /pentest/passwords/wordlists/darkc0de.lst -d hashes -s Mandela2

Step 8: Using Our Hash

Once we have generated our hashes for the particular SSIDs, we can then crack the 

password with cowpatty by typing:

[code]

cowpatty -d hashfile -r dumpfile -s ssid