Изменить MAC-Address

 ManagementObjectSearcher adapterSearch = new ManagementObjectSearcher("root\\CIMV2", "SELECT * FROM Win32_NetworkAdapter");
 
        foreach (ManagementObject networkAdapter in adapterSearch.Get())
        {
            string pnpDeviceId = (string)networkAdapter["PNPDeviceID"];
            Console.WriteLine("Description  : {0}", networkAdapter["Description"]);
            Console.WriteLine(" PNPDeviceID : {0}", pnpDeviceId);
 
            if (string.IsNullOrEmpty(pnpDeviceId))
                continue;
 
            // make sure you escape the device string
            string txt = "SELECT * FROM win32_PNPEntity where DeviceID='" + pnpDeviceId.Replace("\\", "\\\\") + "'";
            ManagementObjectSearcher deviceSearch = new ManagementObjectSearcher("root\\CIMV2", txt);
            foreach (ManagementObject device in deviceSearch.Get())
            {
                string[] hardwareIds = (string[])device["HardWareID"];
                if ((hardwareIds != null) && (hardwareIds.Length > 0))
                {
                    Console.WriteLine(" HardWareID: {0}", hardwareIds[0]);
                }
            }
        }

List<NetworkAdapter> allNetworkAdapters = new List<NetworkAdapter>();
ManagementObjectSearcher searcher= new ManagementObjectSearcher("SELECT * FROM Win32_NetworkAdapter");
 
ManagementObjectCollection networkAdapters_Win32_NetworkAdapter = searcher.Get();
        foreach (ManagementObject tempNetworkAdapter in networkAdapters_Win32_NetworkAdapter)
        {
                allNetworkAdapters.Add(new NetworkAdapter // мой пользовательский класс
                    (
                        tempNetworkAdapter["DeviceID"] == null ? null : tempNetworkAdapter["DeviceID"].ToString()
                    ));
        }