WPA stands for Wifi Protected Access. It is an encryption system to secure WLAN networks. It eliminates all known vulnerabilites in WEP(Wired Equivalent Privacy). WPA uses 128 bit key and 48 bit initialization vector while WEP uses 108 bit key with 24 bit initialization vector. WPA2 is the successor of WPA. Both WPA and WPA2 use temporal key integrity protocol(TKIP) for encryption and pre-shared key(PSK) authentication. The only difference between WPA and WPA2 is that they use Rivest Cipher(RC4) and Advanced Encryption Standard(AES) encryption algorithms respectively. Both can be configured to use counter cipher block chaining mode(CCM) though. They are by far consired most secure for Wifi networks.
So, today we are going to see WPA/WPA2 password cracking with aircrack. For this howto, I am going to use Kali Linux. ( For this howto, if you are running Kali Linux in Vmware or Virtualbox you need to have a compatible wifi usb adapter). I am running Kali Linux in live USB mode(see how to make kali live usb) as my laptop has Atheros adapter. So let’s start.
Once you have booted into Kali Linux, open terminal and type command “iwconfig”. It lists your wireless interfaces just like ifocnfig shows wired interfaces.
We can see that we have a wireless interface wlan0. Now we are going to start monitor mode on our wireless interface. Monitor mode is same as promiscuous mode in wired sniffing. Type command “airmon-ng start wlan0″. We can see below that monitor mode has been enabled on “mon0″.
Now let’s see all the traffic collected by our wireless interface. Type command airodump-ng mon0.
Hit Enter. We can see all the wireless networks available as shown below.
We can see that all the wifi networks are configured with WPA2 or WPA. We are going to hack the network “shunya”. We will collect the shunya’s network traffic into a file. Open a terminal and type command “airodump-ng –bssid <Mac address of wifi access point> -c 13 –write wpacrack mon0″.
–bssid stands for base station security identifier
<MAC address> is the Mac address of access point.
-c is used to specify the channel the wifi network is operating on.
–write to write to a file.
wpacrack is the file name we are writing into.
mon0 is the interface
Hit Enter. We will see the result as below.
We can only hack a WPA/WPA2 protected wifi network by capturing it’s handshake process or association( when the client is trying to connect to the wifi network.). So let’s try to disconnect all the clients connected to the wifi network “shunya” first. Open a new terminal and type the command “aireplay-ng –deauth 100 -a <MAC> –ignore-negative-one mon0″.
–deauth are the deauthentication packets,
100 are the number of deauthentication packets we want to send.
-a stands for access point.
<MAC> is the MAC address of the wifi access point.
This command will send 100 deauthentication packets to the broadcast address of the wifi access point. This will make all the clients connected to the shunya get disconnected. As soon as this happens, all the clients will try to connect back to the wifi network once again. We can see that a WPA handshake has happened in the previous terminal.
Now let’s see where our capture file is located. Type “ls”. We will do dictionary password cracking here. So let’s find out where the dictionaries are. Type command “locate wordlists”. This will show us a number of wordlists available by default in kali linux.
Our captured traffic is stored in .cap file. We will use the wordlist big.txt for cracking the password. Open a new terminal and type command “aircrack-ng wpacrack-01.cap -w /usr/share/dirb/wordlists/big.txt”.
Hit Enter. If our dictionary has the password, the result will be as below. If our dictionary doesn’t have the password, we have to use another dictionary.
Remember that the choice of dictionary will play a key role in WPA/WPA2 password cracking. So that was wpa/wpa2 password cracking with aircrack for you. Hope this was helpful.