Why Should I Care About Wireless Network Security?

Access to a wired network is easy to control because people have to be physically inside your house to plug a computer into the router. With a wireless network, people just have to be in the proximity of your house. Physical barriers such as windows and doors do not control access in this case, so we have to take other steps to block intruders.

The security issue with a wireless network stems from the fact that the signal is omnidirectional. Unlike a wired network, where signals are fairly well contained, the wireless signal goes everywhere in all directions (including up and down for those of you in multistory buildings) for 300 feet or more. Anyone who wants to gain access to your signal need only put a receiver (a computer with a wireless card) inside the signal range.

Very Important

Why would someone want to access your wireless network? Well, there are lots of reasons. One of your neighbors could "leech" onto your network just to receive free Internet access. Although irritating, this is not all that harmful in itself, if all they are doing is browsing the Internet on your dollar. However, "war drivers" (people who drive around looking for unsecured wireless connections) or professional hackers could use the access to obtain your personal information. For example, eavesdropping while you are conducting an online purchase could expose your credit card information. They could also access the computers on your network.

One of the most unusual illicit uses of unsecured home wireless networks also offers perhaps the strongest reason yet to secure your wireless network. Recently, several instances have surfaced in which people conducting illegal activities used unsecured home networks for the anonymity that they can provide. One fellow parked in a neighborhood, easily gained access to an unprotected home wireless network and downloaded huge amounts of illegal child pornography. He was caught and arrested, but because of a traffic violation, not the downloading. (The police noticed the pictures on the computer after they pulled him over.) If someone commits illegal activity in this manner, it can easily be traced to your broadband subscription, and you could end up having to explain to the authorities (and your family) that it was not you or other family members conducting the illegal activity.

We are always amazed when we drive through a neighborhood and check how people have deployed their wireless networks. On one drive recently, we easily found 114 wireless routers, only 45 (roughly 40 percent) of which were protected in any fashion. From such a scan, potential intruders can easily obtain a survey of the available wireless networks, their service set identifiers (SSIDs), channel numbers, and most important, which networks have been secured and which have been left wide open (roughly 60 percent). In Figure 2-1, the networks with a circle and a padlock inside indicate that they are at least using encryption. The circles without a padlock are wide open. Anyone can sit on the street near these houses (or businesses), associate to the access point, and access the Internet or try to break into the rest of the home network. Tools that perform these kinds of searches are free and easy to find and use.

Figure 2-1. Example of Scanning for Wireless Networks in a Neighborhood

Several of the unsecured sites shown in Figure 2-1 are in the same condition that your wireless router is in when you take it out of the box. In other words, these people took their router out of the box, hooked it up, and started using it without enabling wireless security. It is great for getting up and running fast, but if you do not take a few minutes to secure your router (and it really only takes a few minutes), you could be asking for trouble.