Who's in the middle

When your at your local coffee shop or joining that "Free Wifi" hotspot, you might want to think twice!  Anything you send and receive can be "sniffed" without you knowing.  I will demonstrate how easy it is to perform a Man in the Middle (MiTM) attack.  I will setup a "Free Wifi" hotspot and have my test machine connect for some "Free" browsing! You'll need a wireless card that supports packet injection.  The Alfa AWUS036H is a great model and well supported with Backtrack.

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 DISCLAIMER - This is only for educational purposes to help make you aware of the risks with wireless.

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The first step is to ensure your interfaces are up.

Next you'll need to put your card in monitor mode.  Additional commands may be used to resolve warning messages.

Now lets set the channel for our wireless card and the monitor interface.





It is now time to create our "Free Wifi" hotspot.  This command will remain open during the test.  You will see when "clients" connect.










A new interface will be created (at0) and will need be brought up.  We will use brctl to create a bridge so that our "clients" can access the internet through eth0.

Next we'll need to assign IP addresses to the interfaces and bring up the bridge.

At this point all traffic is now routed through the attackers machine.  Tools such as Wireshark, Urlsniff, driftnet, or webspy could be used to monitor "client" traffic.

If you use public wifi,  keep these things in mind.  Using a VPN is a good idea.