Daily Cup of Tech

Wireless networking has been one of the best innovations to the IT industry, both at home and at the office. It provides a great amount of freedom to the user while still giving reasonable speeds. And the cost has dropped so much in the past number of years that it is generally in the price range for the majority of computer users.

Now, one of the issues that has always been in the back of my mind about WiFi and other wireless devices such as cordless phones is the fact that they run in the unlicensed wireless spectrum. This means that pretty much anyone and his dog can put together a low wattage device that runs in that specific frequency range without having to ask anyone’s permission first. This means that if you and your neighbor each have a wireless network set up and you both are running in the same channel and frequency, you can easy cause each other networking problems all quite innocently.

But, what if I wasn’t so innocent? Take, for example, the Wave Bubble. Here are complete plans and instructions for building a low frequency signal jammer. It is small enough to fit in a package of cigarettes, runs of batteries that can be recharged from a USB port, and it is capable of knocking out any wireless signal within a 20 ft radius.

“So what? A 20 ft radius isn’t that big. My server room is larger than that!” This may be but let’s consider the following:

So, let’s say that you are running a small network as depicted in the diagram.

Each access point is connected to the previous access point via the wireless backhaul with the first access point connected wirelessly to the server room. Several systems are accessing each access point, represented in this diagram by the laptops and workstations.

Now, let’s assume that someone were to fire up this WiFi jammer under the desk of an individual user. We would see one user lose connectivity. Not really a big deal.

But, what if they were to run the jammer beside the bottom access point? We would then see all systems that rely on that access point lose connectivity. Starting to get worried, yet?

What if I were to put the jammer beside the middle access point? Now we have three access points and all of the system that rely on them without connectivity.

And if I wanted to be particularly nasty, I’d set up the jammer right in the server room, plugged into the server’s USB port. This would jam all wireless access to the server room along with constantly charging the batteries from the USB port so that the jammer would continue to run indefinitely.

So, now that we are all suitably scared, what can we do to help protect ourselves? Here are a few tips:

1. Always wire your access points. This way, you cannot be jammed from the server.
2. Wire access points directly back to the central switch and try to avoid bridging your connections. This will help prevent a cascade effect.
3. Do periodic audits of your “air space”.
4. Don’t broadcast that you are using wireless technology. Turn off your SSID on your wireless systems.
5. Do not place server rooms on an external wall. This could allow someone to jam your wireless link without even entering your office.
6. Catalog and label all server room hardware. Periodically audit your hardware lists.
7. Tightly restrict physical access to your server rooms.
8. Train all employees to immediately questions unaccompanied strangers in the office.

It is very important that you keep your wireless network safe and secure. Having your network ripped out from under you is almost as bad as having someone access it without proper authorization.

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