April 17, 2014

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Wireless LANs, Security, and Intrusions

News.com has an article about drive-by spam. The idea is that a spammer will find a building with a wireless LAN. The spammer will then connect to that LAN, without permission, from outside the building, and use the building’s email server to send a big load of spam email.

This is abusive behavior. The spammer is exploiting the wireless network owner, who ends up paying for the email, and who might get blamed for spamming. (The network owner can prevent this by tightening up the security of their email system, but this is not cost-free, and it doesn’t excuse the drive-by spammer’s actions.)

The problem here is that wireless nets do not respect property lines, walls, or other physical boundaries. If you’re running a wireless network, it is almost certainly open to people outside your site. This is a security risk for you – drive-by spamming is only one of the ways an outsider could exploit the availability of your network. (And even if you turn on the “secure mode” of your wireless network, you’re probably not safe against a sophisitcated adversary.)

It seems reasonable to adopt the ethical principle that you should not use somebody else’s wireless net without permission. (And if you do use it, you should use it only to access the greater Internet, and not to use their internal servers.)

Now suppose you’re in a public place. You pop your wireless card into your laptop, and it finds a connection. What should you do? How do you know whether you have permission?

The answer is that you don’t know. Maybe the wireless net is open because of an oversight, or because its owner wasn’t able to close it. But maybe it’s open on purpose. Some sites use their wireless nets to provide complimentary service to their customers or to the public. Sharing your network feed is a neighborly thing to do, so an open wireless net might be an invitation rather than a mistake.

How can you tell the difference? Unfortunately, the technology doesn’t help. You just shove your network card into your laptop, and it either does or doesn’t find a connection. There’s nothing in the technology that helps you figure out whether the network’s owner objects to your using it. There might not even be an easy way to find out who the network owner is.

What we need is some kind of social norm to help us out. If “everybody knows” that a network configured one way is meant to be open to the public, and one configured otherwise is not, then the boundaries will be clear. Until then, we’ll just have to do our best to behave reasonably and treat others’ wireless nets with the same respect we should normally afford to others’ property.

Situations like this often invite legislation and legal line-drawing. That seems like a mistake here, as any new law would likely be farther from the “right” answer than the eventual social norm will be. So far I haven’t seen any proposed legislation regulating use of others’ wireless nets, but I wouldn’t be surprised to see some.