You lock your car every single night. You park it in the driveway under a light. You even double-check the handles before walking inside. So how is it possible that someone got into your car without leaving a scratch? It turns out that modern car thieves have moved way beyond slim jims and broken windows. They now use small electronic devices to trick your car into unlocking itself. Over 850,000 vehicles were stolen in 2024 alone. Here is exactly how these thieves operate and what you can do about it.
Your key fob signal can be stolen through walls
Most newer cars use a key fob that sends a wireless signal. When you walk up to your car, the car detects that signal and unlocks. It is convenient, but it also creates a real problem. Thieves have figured out that they can grab that signal without ever touching your keys. They do not need to break into your house. They do not need to steal your fob. The signal travels through doors, walls, and windows, which means your keys sitting on the kitchen counter are broadcasting to anyone who knows how to listen.
This type of crime is called a relay attack. It has been growing more common over the past few years. Insurance expert John Espenschied describes it simply. Criminals “copy and paste” the signal from your fob to fool your car into thinking the key is right next to it. They never force a lock. They never smash glass. Your car just opens for them like it would for you. The whole process takes seconds.
Thieves work in pairs to relay your signal
Here is how the scheme actually works. Two thieves show up at your home, usually in the middle of the night. One person stands near your front door or a window closest to where you keep your keys. That person holds a small electronic device that picks up the faint wireless signal from your key fob inside the house. Even though the signal is weak, the device amplifies it and sends it to the second thief. The second person stands next to your car in the driveway holding another device.
That second device broadcasts the amplified signal right at your car. Your vehicle thinks the key fob is standing right beside it. So it unlocks the doors. In some cases, the car even lets the thief start the engine and drive away. A Nashville resident named Marek Taylor caught this on video and said, “He opened that locked door like it wasn’t even locked.” Taylor had locked his truck just hours before the break-in. The whole thing happened at 3 a.m.
A device called Flipper Zero makes this easy
The devices these thieves use are not some underground black-market gadgets. One popular brand is called the Flipper Zero. Its own website says it “loves hacking digital stuff, such as radio protocols, access control systems, hardware and more.” It was originally designed as a multi-tool for tech professionals and hobbyists. But criminals quickly figured out they could retool it to copy key fob signals, garage door frequencies, and even credit card data. It is small, portable, and disturbingly effective in the wrong hands.
Amazon actually banned the sale of Flipper Zero on its platform because the device was frequently used for card skimming. But you can still buy it from the manufacturer’s website and other retailers. Owning one is not illegal. Using it to steal cars or skim cards absolutely is. Madison, Wisconsin, police officer Wesley Hartkemeyer warns that devices like this “allow criminals to sidestep safety protocols that used to make us feel secure.” The technology is not going away anytime soon.
Car alarms will not save you from this
Most people assume their factory-installed car alarm will protect them. After all, that is what it is there for, right? The problem is that a relay attack does not trigger the alarm. The car thinks a legitimate key fob is being used. It has no reason to sound an alert. From the car’s perspective, everything looks normal. It is like someone unlocking your front door with a perfect copy of your house key. The lock does not know the difference, so it just opens.
This is what makes relay attacks so dangerous. They bypass the exact security features that most car owners rely on. The National Insurance Crime Bureau reported that annual car thefts dropped 17% in 2024 to about 850,708 vehicles. That sounds like progress, but it comes after a massive four-year surge that peaked at over one million thefts in 2023. Vehicle crime remains well above pre-pandemic levels, especially in dense urban areas. Traditional alarms are not enough anymore.
Aluminum foil on your key fob actually works
This sounds ridiculous, but wrapping your key fob in aluminum foil can actually block thieves from stealing its signal. Rocky Casullo of Casullo’s Automotive says that the foil shortens the range of the signal. That makes it much harder for criminals to capture it from outside your home. It is not a perfect solution, and it does look a little silly. But when the alternative is waking up to an empty driveway, a little foil does not seem so bad.
The one trade-off is that you will need to be closer to your car for the fob to work. You might not be able to unlock it from across a parking lot. But that is a small price to pay for added security. Casullo specifically recommends this for people living in high-crime areas where relay attacks are more common. You probably already have a roll of foil in your kitchen, so this costs you absolutely nothing to try tonight.
RFID-blocking bags are a better long-term fix
If wrapping your fob in foil feels too DIY, there is a more polished option. RFID-blocking pouches, also called Faraday bags, are specifically designed to block wireless signals from escaping. You just drop your key fob in the pouch when you get home, and the signal is completely contained. Thieves standing outside with their relay devices will detect nothing. Insurance expert John Espenschied describes these as “little sleeping bags for your key fob that block the signal from escaping.”
You can find Faraday bags on Amazon for under $15. Some come in multi-packs, which is helpful if you have more than one key fob in the house. Residents in the Nashville neighborhood where relay attacks were caught on camera said they immediately started investing in RFID bags after seeing the footage. It is a simple purchase that takes the relay attack completely off the table. Just make sure you actually use it every time you come home, not just when you remember.
Where you store your keys at home matters
Think about where you drop your keys when you walk in the door. A hook by the front entrance? A bowl on the hallway table? A shelf near a window? These are the worst possible spots. Remember, the thief with the relay device stands near your house to grab the signal. The closer your keys are to an exterior wall, door, or window, the easier it is for them to pick up the fob’s frequency. Most people store keys in the most convenient spot, which is usually the most vulnerable one.
Espenschied recommends moving your key fob away from doors and windows. The middle of your house or an interior room is a much better spot. Some people even keep their fobs in a drawer in a back bedroom. The goal is to put as much distance and building material between your fob and the outside walls as possible. Combined with a Faraday bag, this makes it extremely difficult for thieves to reach the signal. A small change in habit can make a big difference.
Old-school steering wheel locks still deter thieves
Remember The Club? That bright red bar your parents or grandparents locked across the steering wheel? It might seem outdated in 2025, but it still works as a visual deterrent. Even if a thief manages to unlock your car and start the engine, a steering wheel lock makes the vehicle much harder to drive. Most criminals want a quick grab. If they see something that slows them down, they will often move on to an easier target.
Espenschied calls the steering wheel lock “old school, but an extra layer of not worth the hassle” for thieves. You can pick one up at Walmart or AutoZone for around $25 to $50. It takes about five seconds to attach. Is it a guarantee? No. But it adds one more obstacle between a thief and your car. Layering multiple security steps together gives you the best protection against theft. Sometimes the old methods and the new methods work best as a team.
Disabling keyless entry and updating software helps
Did you know that some vehicles let you turn off keyless entry entirely? Check your car’s settings menu or your owner’s manual. Disabling this feature means the fob will not constantly broadcast a signal. That eliminates the relay attack method altogether. You will need to manually press the unlock button on your fob, but that tiny inconvenience is worth the added peace of mind. Not every car offers this option, but it is worth checking yours.
Keeping your car’s software updated is also important. Manufacturers sometimes release security patches that fix vulnerabilities in keyless entry systems. You can usually check for updates at your dealership or through your car’s built-in system. Espenschied lists software updates as one of his top recommendations for staying ahead of security vulnerabilities. Between disabling passive keyless entry and installing the latest software, you close two major gaps that relay attackers depend on. These are free steps that anyone can take today.
Locking your car is still important, but it is no longer enough on its own. Thieves have caught up with modern technology, and the rest of us need to adapt. Whether it is a $0 roll of aluminum foil, a $15 Faraday bag, or a $30 steering wheel lock, every layer of defense you add makes your car less appealing to criminals. The best strategy combines several of these steps together. Take a few minutes tonight to move your keys, check your settings, and make your vehicle a harder target.
