Bypassing MAC Address Filtering

One security measure that many people are now applying in wireless networks is filtering by MAC address. This implementation only allows works only network cards with certain MAC address to connect to your network. However a knowledgeble person can bypass this obstacle. With free tools like Ethereal you can determine one or more MAC address that are allowed to the network. If you know such a MAC address then you can use that address by modifying the registry in Windows XP.

The HOW?
Changing your MAC address in Windows is not a difficult process. The steps that you need to take vary slightly between Windows XP and Windows 2000.

Note: Modifying the Registry can be dangerous and can cause the system to become unstable if it is done incorrectly.
Go to Start | Run and type in regedit. This will start the Registry Editor

Expand the HKEY_LOCAL_MACHINE | System | CurrentControlSet | Control folders

Scroll down to the Class folder and expand it. Next, scroll down to the {4D36E972-E325-11CE-BFC1-08002bE10318} folder and expand it. This folder contains the Windows XP Registry information regarding network adapters installed on your system. Scroll through each folder until you find your wireless network adapter

From the Registry Editor menu, choose Edit | New | String Value. This creates a new REG_SZ string and prompts for a value. Type NetworkAddress. Now, right-click the NetworkAddress key that was just created and choose Modify. Enter the new MAC address you want to use in the Value Data field and click OK.

Simply close the Registry Editor and reboot the system. The new MAC address is assigned as the system starts. Verify this by typing ipconfig /all.

To return the MAC address to its original, hardware-assigned value, delete the key that you just created and reboot the system.

Note: Changing the MAC address to a random address may cause the adapter not to bind correctly and prompt the card to become unresponsive to the network.

ciao… 🙂 


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