Bluesnarfing is the unauthorized access of information from a wireless device through a Bluetooth connection, often between phones, desktops, laptops, and PDAs. This allows access to a calendar, contact list, emails and text messages, and on some phones users can copy pictures and private videos.
Current mobile software generally must allow a connection using a temporary state initiated by the user in order to be 'paired' with another device to copy content. There seem to have been, in the past, available reports of phones being Bluesnarfed without pairing being explicitly allowed. After the release of this vulnerability vendors of mobile phone patched their Bluetooth implementations and, at the time of writing, no current phone models are vulnerable to this attack.
Bluesnarfing is much more serious than Bluejacking, but both exploit others' Bluetooth connections without their knowledge. Any device with its Bluetooth connection turned on and set to "discoverable" (able to be found by other Bluetooth devices in range) may be susceptible to Bluejacking, and possibly to Bluesnarfing when, and if, Bluesnarfing of the current Bluetooth security becomes possible.
By turning off this feature, the potential victim can be safer from the possibility of being Bluesnarfed; although a device that is set to "hidden" may be Bluesnarfable by guessing the device's MAC address via a brute force attack. As with all brute force attacks, the main obstacle to this approach is the sheer number of possible MAC addresses. Bluetooth uses a 48-bit unique MAC Address, of which the first 24 bits are common to a manufacturer . The remaining 24 bits have approximately 16.8 million possible combinations, requiring an average of 8.4 million attempts to guess by brute force.
Because Bluesnarfing is an invasion of privacy, it is illegal in many countries.
It is important not to confuse Bluesnarfing with Bluejacking. While Bluejacking is essentially harmless as it only transmits data to the target device (rather than retrieving data), Bluesnarfing is the theft of information from the target device.