It’s not only about people getting to use your WIFI for free, but also about the security of the files and information you’ve actually got on your personal network.

Not too long ago, I was checking my personal security, trying to hack my own password with some powerful software I got hold off that ran on Ubuntu. While trying out the software, I also managed to retrieve the WIFI password of four or five neighbouring networks. Now what was even worse was that three of them still had the default router username and password, so I got access to being able to control their routers and snoop around their phone logs. On one on the networks I managed to obtain access to a hard drive with tons of personal files.

Now that was really a one off thing for trial purposes, but it showed me that one has to be wary of WPS, the actual security protocol, router passwords (change default) and personal network security. Fortunately, I’m rather ethical, so besides learning how to do it, I was never inclined to doing any harm.

Edit: Back then I used Wifislax. There are probably better alternatives now, but that did the job at the time. Another interesting feature was to use it as a WIFI jammer: you could target a WIFI and basically overload it with petitions. You have to be pretty near though for this to work, but when I tried it, it caused the jammed wifi to reboot itself repeatedly if I recall correctly (no need to be actually logged-on the the target network).