DEF CON has a lot of odd talks, but the successful hacking of a vibrator by two researchers from New Zealand drew a big crowd.

The two-person team of g0ldfisk and follower got hold of the schematics for the We Vibe 4 Plus, a U-shaped vibrator that can be controlled via Bluetooth using a remote control or a smartphone app. The wireless functions mean the device's makers had to report its details with the United States the Federal Communications Commission, and that filing allowed the hackers to figure out a way to crack the device.

The We uses a Texas Instruments CC2541 processor with a dated 2.4GHz BlueTooth chip. Because there was no certificate pinning on the device it turns out it was fairly easy to hack, and find out what information it collects and transmits to the mobile app.

“We have had problems picking up the signal,” said Follower. “It turns out the human body is a surprisingly efficient faraday cage.”

The team managed to decipher the Bluetooth command strings and manipulate the We using a desktop computer. They reported the job was relatively simple - the Bluetooth data string is only eight bytes long and the first byte controls the device’s mode.

The two also found that the makers of the We collect exactly when the device is used, which of the ten vibration modes they are using, and even the temperature of the device. All this data is stored on corporate servers and in the terms and conditions of the device the manufacturer reserves the right to pass it on to the authorities.

If that provision sounds odd, know that this type of device is illegal in many places - including the Yellowhammer State of Alabama, some parts of Georgia, and until recently Texas. Using such devices is a criminal matter and there have been prosecutions.

The duo noted that this isn’t something hackers should try on other people’s devices, since technically it may be possible to charge someone with initiating unwanted sexual contact if they do. But they do want manufacturers to tighten up their security practices and will be setting up a campaign to make sex toys safer for all. ®