Bluejacking
Sending unsolicited messages to nearby Bluetooth devices; the message does no harm to the device, but it can lure the user into a harmful response, much as spam or phishing does.
Bluejacking is the sending of unsolicited messages to a Bluetooth device within radio range, by abusing features meant for exchanging contact cards or short notes. NIST SP 800-121 Rev 2, Guide to Bluetooth Security, lists it among the Bluetooth-specific attacks and compares it to spam and phishing against email users. The message on its own does not damage the device or take anything from it. The risk lies with the person who receives it: a message written to deceive can persuade the user to reply, save a new contact or take some other action that helps the sender.
Study sources commonly teach bluejacking alongside two other Bluetooth attacks, and the three are told apart by what the attacker gains. Bluejacking delivers messages only. Bluesnarfing takes data from the device. Bluebugging takes control of the device and its functions. Setting a device to non-discoverable when it does not need to be found, and declining contact or pairing requests from unknown devices, reduce exposure to all three.
Exam relevance: a scenario is likely to describe people in a public place receiving strange messages from an unknown nearby device, with no data lost. That points to bluejacking. Candidates are expected to see it as the lowest-impact of the three, while recognising that it can open the door to social engineering.