Windows Wireless vulnerability
Brian Krebs has a post today on a Windows wireless networking “feature” which can be somewhat of a security risk. You see, it seems that With wireless networking enabled, Windows remembers the last wireless SSID that you connected to, so let’s say you were at a public Wireless access point called “Bob’s hotel” and you carry your laptop somewhere else. When the machine boots up, Windows tries to find “Bob’s hotel”, but of course, it’s not available at this other location, so… it assigns a 169.254.x.x ip address and broadcasts looking for “Bob’s hotel” the most recent wireless lan.
So, that makes it very easy for another person on another pc to find the broadcasts and quickly get put in the same 169.254.x.x subnet and voila the two machines have set up an ad-hoc wireless network (without the awareness of the user who had made use of Bob’s Hotel wireless networking… (In fact they may not have been aware that their laptop had made use of THAT wireless connection.) Of course, with a firewall enabled you’ve mitigated a large degree of the risk of this. Another solution is to switch off your wireless radio. (Many laptops now have a little on off button or switch that will enable/disable the wireless. Many times there’s a led light to indicate that it’s active.)
Another way to work around this is to set Windows to only associate with “infrastructure” networks and not ad-hoc networks.
To do this, go to “Start,” “Control Panel,” “Network Connections,” and then right click on the entry labeled “wireless network connection” and select “Properties” from the drop down menu. Then click on the “Wireless Networks” tab, and then on the “Advanced” tab at the bottom of that window. A box should pop up that gives you three buttons to choose from: Select the one next to “Access point (infrastructure) networks only.”
Microsoft exects to change Windows default behavior in this area with the next round of Service Packs. (SP3 of XP.) Bottom line, if you have wireless built in on your laptop, be aware of how to enable/disable it AND make sure that your laptop has a software firewall.