When you switch on your mobile’s Bluetooth and search for new devices, you will find lots of Bluetooth mobile phones around, and you can download their contacts even control their mobile phones with the help of certain tools. Many people may leave their mobile phones in invisible mode, but this is not safe enough.
We’ll make a small experiment. Make sure your laptop has a Bluetooth adapter and operating system is SuSe Linux 9.3 or others that have the Bluetooth tools used below.
When all is set, run hcitool and type hcitool scan, your laptop will quickly find a few Bluetooth mobile phones depending on how many people are there, but you will never get disappointed. However you can only find those mobile phones whose Bluetooth is turned on and in discoverable mode. So we need to use BTScanner to perform a brute force scan, type BTScanner and your laptop will start to search, this way you can find those Bluetooth mobile phones in invisible mode.
This shows even if your mobile phone is in invisible mode, others can find you without much effort.
Update, newer and higher version Bluetooth may come with enhanced security for you to withstand this kind of attack. Now on the market Bluetooth 4.0 enabled devices are on the increase.