apt-get install bridge-utils
- Finding out about the access point (AP) you want to imitate, and then actually imitating it (i.e. creating another access point with the same SSID and everything). We’ll use airmon-ng for finding necessary info about the network, and airbase-ng to create it’s twin.
- Forcing the client to disconnect from the real AP and connecting to yours. We’ll useaireplay-ng to deauthenticate the client, and strong signal strength to make it connect to our network.
- Making sure the client doesn’t notice that he connected to a fake AP. That basically means that we have to provide internet access to our client after he has connected to the fake wireless network. For that we will need to have internet access ourselves, which can be routed to out client.
- Have fun – monitor traffic from the client, maybe hack into his computer using metasploit.
Information Gathering – airmon-ng
To start monitor mode on the available wireless interface (say wlan0)-
airmon-ng start wlan0
To capture packets from the air on monitor mode interface (mon0)
After about 30-40 seconds, press ctrl+c and leave the terminal as is. Open a new terminal.
Creating the twin
airbase-ng -a <BSSID here> –essid <ESSID here> -c <channel here> <interface name>
If you face any problems, a shorter code will be-
airbase-ng –essid <name of network> mon0
Remove the angular brackets (< & >) and choose any channel that you want. Also, the BSSID can be randomly selected too, and doesn’t have to match with the target. The interface would be mon0 (or whatever is the card you want to use) . The only thing identical about the twins has to be their ESSIDs (which is the name of the network). However, it is better to keep all parameters same to make it look more real. After you are done entering the parameters and running the command, you’ll see that airbase turned your wireless adapter into an access point.
Note : We will need to provide internet access to our client at a later stage. Make sure you have a method of connecting to the net other than wireless internet, because your card will be busy acting like an AP, and won’t be able to provide you with internet connectivity. So, either you need another card, or broadband/ADSL/3G/4G/2G internet.
|Man in the middle attack : Pic Credits: owasp.net|
Telling the client to get lost
aireplay-ng –deauth 0 -a <BSSID> mon0 –ignore-negative-one
The 0 species the time internal at which to send the deauth request. 0 means extremely fast, 1 would mean send a packet every 1 seconds, 2 would mean a packet every 2 seconds, and so on. If you keep it as 0, then your client would be disconnected in a matter of seconds, so fire up the command, and press ctrl+c after a few seconds only. Note that the deauth is sent on broadcast, so all the clients (not just one) connected to the network will disconnect. Disconnecting a specific client is also possible.
Not the real one, but why the fake one
Even after being disconnected from the real AP, the client may choose to keep trying to connect to the same AP a few more times, instead of trying to connect to ours. We need to make our AP stand out, and for that, we need more signal strength. There are 2 ways to do that-
- Physically move closer to the client.
- Power up your wireless card to transmit at more power.
The latter can be done with the following command –
iwconfig wlan0 txpower 27
Here 27 is the transmission power in dBm. Some cards can’t transmit at high power, and some can transmit at extremely high power. Alfa cards usually support upto 30dBm, but many countries don’t allow the card to transmit at such powers. Try changing 27 to 30 and you’ll see what I mean. In Bolivia, however, you can transmit at 30dBm, and by changing the regulatory domain, we can overcome the power limitation.
iw reg set BO
iwconfig wlan0 txpower 30
It is strongly advised to not break laws as the transmission limits are there for a reason, and very high power can be harmful to health (I have no experimental evidence). Nevertheless, the client should connect to you if your signal strength is stronger than that you the real twin.
Note : If you are unable to get your client to connect to you, there is another option. You can leave him with no options. If you keep transmitting the deauth packets continuously (i.e. don’t press ctrl+c after the client has disconnected), he will have no choice but to connect to you. However, this is quite an unstable situation, and the client will go back to the real twin as soon as it gets the chance.
Give the fake AP internet access
- x0 – This has internet access
- at0 – This is create by airbase-ng (wired face of the wireless access point). If you can somehow give internet access to at0, then the clients connected to your fake wireless network can connect to the net.
- evil – This is an interface that we will create, whose job will be to actually bridge the networks.
brctl addbr evil
This will create the bridge. Now we have to specify which two interfaces have to be bridged-
brctl addif evil x0
brctl addif evil at0
We can assign an IP to the interfaces and bring them up using-
ifconfig x0 0.0.0.0 up
ifconfig at0 0.0.0.0 up
Also bring up the evil interface (the interfaces aren’t always up by default so we have to do this many times)
ifconfig evil up
Now to auto configure all the complicated DHCP settings, we’ll use dhclient
dhclient3 evil &
Finally, all the configurations have been completed. You can execute ifconfig and see the results, which will show you all the interfaces you have created.
Officially, the evil twin attack is complete. The client is now connected to your fake network, and can use the internet pretty easily. He will not have any way to find out what went wrong. However, the last objective remains.