X10 home automation devices control household systems over AC power lines. In the past their online pop-up ads were pervasive and hard to avoid and these devices are fairly common today.
Researchers Dave Kennedy, aka Rel1k, and Rob Simon, aka Kc57, revealed two X10 hacking devices at the recent Defcon 19 conference in Las Vegas.
The X10 Sniffer to determine what’s connected to the power network and monitor what the devices are doing, and the X10 Blackout, which can jam signals to interfere with the operation of lights, alarms, security cameras and other devices.
The researchers demonstrated the Sniffer and Blackout devices they designed that plug into a power socket inside or outside a house or even into an outlet in a house nextdoor, since signals can leak out from a house and carry for some distance. Kennedy said that while testing one of the devices from his house in Ohio, he picked up signals from home automation systems belonging to 15 neighbors.
These tools can be programmed with whatever system commands the hacker desires. The X10 protocol is publicly documented, and it can be easily implemented using MCUs. While we couldn’t find the Defcon device plans or code online, there is a fairly detailed Microchip app note on how to implement the X10 protocol using the PIC 16F877A including both schematic and source code. If you want to try an X10 hack, this app note looks like a good place to start.