Avoid Getting Hacked with Wireless LAN Tests - dummies

Avoid Getting Hacked with Wireless LAN Tests

By Kevin Beaver

After you have a wireless card and wireless testing software, you’re ready to roll. Start testing to avoid those pesky hackers. The first tests you should perform gather information about your WLAN.

Check for worldwide recognition

The first test requires only the MAC address of your AP and access to the Internet. You’re testing to see whether someone has discovered your WLAN and posted information about it for the world to see. Here’s how the test works:

  1. Find your AP’s MAC address.

    If you’re not sure what your AP’s MAC address is, you should be able to view it by using the arp -a command at a Windows command prompt. You might have to ping the access point’s IP address first so the MAC address is loaded into your ARP cache.


  2. After you have the AP’s MAC address, browse to the WiGLE database of WLANs.

  3. Register with the site so you can perform a database query. It’s worth it.

  4. Select the Query link and log in.

  5. To see whether your AP is listed, you can enter such AP information as geographical coordinates, but the simplest thing to do is enter your MAC address in the format shown in the example for the BSSID or MAC text box.


    If your AP is listed, someone has discovered it — most likely via wardriving — and has posted the information for others to see. You need to start implementing the security countermeasures as soon as possible to keep others from using this information against you! There are numerous Wi-Fi “locator” apps for mobile devices as well.

Scan your local airwaves

Monitor the airwaves around your building to see what authorized and unauthorized APs you can find. You’re looking for the SSID (service set identifier), which is your wireless network name. If you have multiple and separate wireless networks, each one may or may not have a unique SSID associated with it.

Here’s where the freebie tool NetStumbler comes into play. NetStumbler can discover SSIDs and other detailed information about wireless APs, including the following:

  • MAC address

  • Name

  • Radio channel in use

  • Vendor name

  • Whether encryption is on or off

  • RF signal strength (signal-to-noise ratio)

The information that you see here is what others can see as long as they’re in range of your AP’s radio signals. NetStumbler and most other tools work by sending a probe-request signal from the client. Any APs within signal range must respond to the request with their SSIDs — that is, if they’re configured to broadcast their SSIDs upon request.


When you’re using certain wireless security assessment tools, including NetStumbler and CommView for WiFi, your adapter might enter passive monitoring mode. This means you can no longer communicate with other wireless hosts or APs while the program is loaded.