Garage doors may be vulnerable to being opened remotely by hackers using little more than a childrens' toy, a security researcher has proven this week.

The repurposed tool has been branded OpenSesame by its creator Samy Kamkar, who built it out of a discontinued Mattel toy called IN-ME, adding an antennae and an open-source hardware add-on. Although no longer available, Softpedia notes that the toy is a pocket computer that allows kids to chat to eachother, and can still be found on eBay for as little as $12.

The proof-of-concept attack affects basic, fixed code garage door security, for which the most advanced would leave 4,096 possible combinations. Kamkar claims that it would take around 29 minutes to breach the lock by brute-force if the details of the system were known to the hacker.

“It’s a huge joke,” says Kamkar, as quoted by Wired. “The worst case scenario is that if someone wants to break into your garage, they can use a device you wouldn’t even notice in their pocket, and within seconds the garage door is open.”

Kamkar then optimized his method further, finding that by removing the wait times between code guesses and removing redundant transmissions he was able to being the time for attack down to just eight seconds.

Although Kamkar has made the source code for OpenSesame available to the public, it's in a bricked state to prevent abuse. The security researcher explained: “It almost works, but just not quite, and is released to educate. If you are an expert in RF and microcontrollers, you could fix it, but then you wouldn't need my help in the first place, would you?”

More helpfully, Kamkar has provided a video to help the public recognize if their garage door is susceptible to attack, and advises "rolling code" security systems are much more secure.