Your SSID Isn’t Hidden Forever In the Test Lab Eric Geier
In the Test Lab
To prove what I'm saying above is accurate, I'll share with you my experience in the Lab. Warning: Hard hats required beyond this point!
I booted up AirMagnet's Laptop Analyzer to verify the test network was closed (SSID broadcasted disabled). As you see in the figure (click for the full screen), the SSID isn't contained in the beacons. As expected, the SSID field is blank.
I then captured packets while booting up my laptop. As you can see in this figure (click for full screen), the Association Request frame from the laptop's wireless client contains the SSID of the network, which is WirelessGuru. Now, that's a problem.
I also noticed that occasionally the wireless client on the seemingly hidden network would broadcast probe requests and the access point would reply with the closed network's SSID. This scenario provides yet another way for wireless analyzers to pick up the hidden SSID. Probe responses are part of the active scanning method wireless clients use to find networks. Thus, a hacker can get the SSID immediately rather than wait until a user connects to the network. Manufacturers implement scanning methods in different ways; the process won't be the same for all wireless clients.
Things to Remember
Okay, what do you really need to know about disabling SSID broadcasting? Keep the following in mind:
The disabling of SSID broadcasting may help secure your wireless network by hiding your network from casual users.
Readily available analysis tools will spot the network's SSID in a matter of time, no matter what you do.
Using the hidden SSID feature on your network doesn't excuse you from using other methods like WEP or WPA to further secure your network.
The bottom line? Just don't depend too much on disabling SSID broadcasting for securing your network.
Eric Geier is a computing and wireless networking author and consultant. He is employed with Wireless-Nets, Ltd., a consulting firm focusing on the implementation of wireless mobile solutions and training. He is an author of Geeks on Call - Wireless Networking: 5-Minute Fixes and Geeks on Call - PC's: 5-Minute Fixes published by John Wiley & Sons.
