Your car is always listening. Not for your voice, like the Amazon Echo or Siri, but for an electronic signal, such as the coded "unlock" signal from your electronic key fob.
If it's a newer car model, you might not have to press any buttons; just approach your car and the doors will unlock automatically. In some cars, the engine will even turn on.
Wirelessly unlocking your car is convenient, but it comes at a price. Specifically, the key fob's signal is easy for criminals to intercept. That lets them open your car without setting off any alarms.
If you have a true keyless car model, they might be able to just drive away. Let's look at how criminals pull this off and what you can do to keep your car safe.
How your car's security system works
As you've probably noticed, you can't just open your car with any old radio signal. You need your specific key fob to do the job, and there's a reason.
A key fob uses a computer chip to create a unique code that it sends to your car's security system. The car also has a chip using the same algorithm to generate codes. If the codes match up, then the car opens. There's a bit more to it than that, but that's the basic explanation.
How criminals attack #1: Monitoring wireless signals
Since each key fob/car security pair is unique, and each one can create billions of codes, hackers don't stand a chance. Or at least that was the theory. It turns out a popular system from Megamos Crypto isn't as secure as everyone thought.
Researchers at Radboud University in the Netherlands and the University of Birmingham found that by intercepting the wireless signal just twice, they could narrow down the possible combinations from billions to just 200,000. After that, a computer can figure out the code in just half an hour and unlock the car.
In a real-world application, a thief could sit on a street gathering wireless signals as car owners enter and exit their vehicles. Then overnight they could steal a number of cars. Tap or click here to find out if your car is at risk from this kind of attack.
Still, that takes a skilled car thief or hacker to carry out this kind of attack, so the odds of it happening to you are slim. However, thanks to always-on key fobs, there's another risk that's much more likely to happen.
How criminals attack #2: Relay boxes capture signals
Always-on key fobs present a serious weakness in your car's security. As long as your keys are in range, anyone can open the car and the system will think it's you. That's why newer car models won't unlock until the key fob is within a foot.
However, criminals can get relatively cheap relay boxes that capture key fob signals up to 300 feet away, and then transmit them to your car.
Here's how this works. One thief stands near your car with a relay box while an accomplice scans your house with another one. When your key fob signal is picked up, it is transmitted to the box that's closer to your car, prompting it to open.
In other words, your keys could be in your house, and criminals could walk up to your car and open it. This isn't just a theory either; it's actually happening.
Fortunately, there are some simple steps you can take to keep hackers from stealing your signal.
4 ways to 'foil' car thieves
There are a few easy ways to block criminals' amplified signals. You can buy a signal-blocking pouch that can hold your keys, like a shielded RFID blocking pouch.
Tip 1: Stick in the fridge...
If you don’t want to spend money on gadgets to scramble your key fob's signal, you can stick your it in the refrigerator or freezer. The multiple layers of metal will block your key fob's signal. Just check with the fob's manufacturer to make sure freezing your key fob won't damage it.
Tip 2: ...or inside the microwave (but DON'T turn it on)
If you're not keen to freeze your key fob, you can do the same thing with your microwave oven. (Hint: Don't turn it on.) Stick your key fob in there, and criminals won't be able to pick up its signal. Like any seasoned criminal, they'll just move onto an easier target.
Tip 3: Wrap your keyfob in foil
The 'fridge and microwave work well when you're at home, but you can't exactly walk around with heavy appliances, right? So, when you're out and about, here are two tips for protecting your keys.
Because metal can block your key fob's signal, you can wrap it in aluminum foil. While that's the easiest solution, aluminum foil can leak the signal if you don't wrap it tightly. Plus, walking around with a foil-wrapped key looks a little silly. You could make a foil-lined box to put your keys in, if you're in a crafting mood, or try the next solution.
Tip 4: Get an RFID blocker
This kind of signal stealing isn't just a problem for car key fobs. Newer passports and other identification contain radio frequency identification (RFID) chips. Criminals can use a high-powered RFID reader to steal your information from a distance. You can find RFID blockers at most electronics stores, and below are links to two for sale at Amazon.