Bluetooth devices, particularly mobile phones, are at risk from two types of attack from nearby or passing devices, bluejacking and bluesnarfing. A bluejacking attack involves sending text messages to the mobile phones of any users who are within range, and it could be used both maliciously and for ‘bluespam’. A bluesnarfing attack is potentially more serious, and involves the theft of all contact information stored in the phones. Not all phones are vulnerable to these sorts of attacks and as manufacturers respond to the discovery of these vulnerabilities, so there will be changes. At the moment (January 2005), it is said that Nokia 6310, 6310i, 8910 and 8910i models are at greatest risk. Apparently, “on some models of phone, you are only vulnerable to attack if you are on visible mode; however, there are other models of phones where you are vulnerable even in non-visible mode”.
The only defence is to turn Bluetooth off.