10.12.08

aircrack-ng and my Alfa Network AWUS036H on Ubuntu Hardy

Posted in OpenSourceSoftware, Linux Distributions, Ubuntu, Security, Wireless at 8:38 pm by Edward Bjarte Fjellskål

I finally got my Alfa AWUS036H USB adapter yesterday, and I got some hours to play with it today. First I saw that the module rtl8187 did not seem to work with my new adapter. A quick google search pointed me in a direction on how to get it up and running, ready for aircrack-ng even. I followed this howto on setting up the adapter, and then I watched this movie on how to crack a WEP network with aircrack-ptw. I tried it out for my self, and it worked right a way… phun! :) I normally use a WPA-PSK network at home, so that was what I was aiming at…

Reading the aircrack-ng WPA/WPA2 howto, I started to try it out… I did several passes at my network, but though I believed I did everything *perfect* the aircrack-ng did not find my WPA-PSK pass phrase (and I know my own pass phrase!). I started googling, and found several similar entries, but non that seem to be helping me out. I connected to the IRC channel for aircrack-ng on Freenode, and popped the question… Two minutes afterwards (Thanks to Mister_X), my problem was solved and I had hacked my WPA-PSK network. The issue seems to be (From my googleing) with dual core processors and the amount of pass phrases >=8 chars in the password file (See this post). The simple solution is to add -p 1 to aircrack-ng (Set this option to the number of CPUs to use (only available on SMP systems). By default, it uses all available CPUs).

So after only ~4 hours (including making and eating dinner), I had cracked my network in WEP and in WPA-PSK (”cracked” when it comes to WPA-PSK) mode :)

Second, so many wireless Access Points I see with my Alfa… It’s rather cool to have such a powerful wireless adapter!