Bluetooth Discoverability
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Keeping a Bluetooth device in "discoverable" mode allows other gadgets with Bluetooth to locate it within a certain range.
Before we dive into Bluetooth surveillance, we'll want to take a look at how Bluetooth itself works and understand what makes the technology traceable. Bluetooth devices use the free, 2.4-gigahertz radio band known as ISM, which stands for industrial, scientific and medical devices. The band is unlicensed for low-power use, so headsets and other Bluetooth accessories use very little in the way of batteries. While any two Bluetooth devices can share data at a range between 10 and 100 meters (33 and 328 feet), phones usually operate at the former, laptops at the latter. Any Bluetooth device can communicate with up to seven other devices at a time.
After you turn any Bluetooth-capable device on, the most basic security feature on it is the ability to go into one of two modes: "discoverable" or "non-discoverable." This information is typically found in the "settings" option of a device's control panel, where you can select whether or not your phone or laptop is visible to others within the area.
If several Bluetooth devices are set on discoverable mode, they all have the ability to search for and locate each other, so long as they remain within range. Every device has its own address, a unique 48-bit identifier with six bytes of information that might look like this: 01:23:45:67:89.10. The first three bytes (01:23:45) are assigned to the specific manufacturer of the device, while the last three bytes (67:89:10) are assigned by the manufacturer. These make each device entirely unique.
So how could someone track your movement if you left your phone on discoverable? Would they have to follow you around all day long, or is there a simpler way? To learn how a Bluetooth surveillance network is set up, read the next page.
Since many terms related to Bluetooth surveillance use some variation of the Bluetooth brand name, it helps to get a few sorted out.
Bluejacking, a prank that involves sending fellow Bluetooth users unsolicited text messages, doesn't actually have anything to do with hijacking, even though the name implies it. The term is simply a hybrid of Bluetooth and "ajack," the username of the Malaysian IT who discovered the glitch and spread the news over the Internet.
Bluejacking, although potentially irritating to users who don't want any part of the joke, won't harm or steal anyone's information. Bluesnarfing, on the other hand, happens when an attacker reads, changes or copies information from a person's phone, such as a phone book, address book or calendar. More serious infringements of bluesnarfing include taking over someone's phone and using it to make phone calls, send text messages or surf the Web.
