Sure, cracking WEP (Wired Equivalent Protection) on regular wifi networks might be old news, but not when it’s now something almost anyone can try (at their own risk of course). This video by Oliver Greiter of EthicalHack.org shows how you could easily reveal a hidden SSID and hack WEP encryption in about 10mins on a Mac with just KisMac (realistically, time required varies with encryption level).
What you need:
1. KisMac (Mac OS X version of Kismet)
2. A prism2 chipset wireless adapter (Unfortunately, Airport Extreme doesn’t work for cracking yet)
If you’re wondering how you can get this particular wireless adapter, the video shows Oliver using a prism2 usb adaptor, which is widely used and pretty cheap, e.g. D-Link DWL-122. Just beware that these manufacturers tend to change their chipsets without warning so check around first.
How do you protect yourself then?
Since WEP has been known to be a relatively weak form of protection, it still forms a good deterrent. If someone’s wardriving around your neighborhood, he’s likely to pick on an easier target like an open network, than to pick a WEP encrypted one. Still if you have to use WEP (being compatible with most devices), at least use it in conjunction with MAC address filtering.
Interestingly I used to turn off WEP and only use MAC filtering since I though WEP was useless… to my horror I discovered that MAC filtering alone was easy to circumvent since it’s much easier to clone a MAC address than to crack WEP. I discovered this when I found an intruder on my wifi network using one of my machine’s addresses. For the best form of protection though, try WPA or better still, authenticate your network users using a VPN server. You can learn more about wireless security on Wikipedia.
See ethicalhack.org for a higher quality Quicktime version for the video.