The Motorola PEBL U6 08.83.76R, the Motorola V600, and possibly the Motorola E398 and other Motorola P2K-based phones does not require pairing for a connection related to the Headset Audio Gateway service, which allows user-assisted remote attackers to obtain AT level access and view phonebook entries and saved SMS messages by connecting on Bluetooth channel 3 and tricking the user into pressing Grant, aka a "Blueline" attack. NOTE: while user-assisted, the attack is made more feasible because of a GUI misrepresentation issue that allows a default message to be replaced by an attacker-specified one.
https://exchange.xforce.ibmcloud.com/vulnerabilities/25402
http://www.vupen.com/english/advisories/2006/1045
http://www.securityfocus.com/archive/1/428431/100/0/threaded
http://www.digitalmunition.com/DMA%5B2006-0321a%5D.txt
http://secunia.com/advisories/19319
http://lists.grok.org.uk/pipermail/full-disclosure/2006-March/044287.html