Understanding Car Theft by Relay Attack: How It Works and How to Prevent It
Relay attacks have become one of the most common and effective methods of stealing modern vehicles equipped with keyless entry and push-button start systems. This form of car theft doesn’t require breaking windows, hotwiring, or even having the key, it simply relies on exploiting the wireless communication between your car and its key fob.
How Relay Attacks Work
Key fobs for modern, push-to-start vehicles constantly emit a low-frequency signal to communicate with the vehicle. When you’re near your car, the vehicle detects the signal and allows you to unlock and start the engine without pressing a button on the fob. In a relay attack, two thieves work together using electronic relay (signal repeater) devices. One stands near your home, front door, or garage and uses a signal amplifier to capture the signal from your key fob inside the house. That signal is then transmitted to a second device held by the other thief standing near the car. The car “believes” the key is present and unlocks and starts as if the owner were nearby.
Relay theft happens most often at home, but not always. Thieves also carry out these attacks in public places like parking lots, shopping centers, or gas stations. One thief may follow a driver and get close enough to capture the key fob signal while the driver is distracted or walking away. This allows the second thief to open and drive off with the car shortly after the driver has parked.
How to Protect Against Relay Attacks
- Use a Faraday pouch or box: These signal-blocking containers prevent your key fob’s signal from being intercepted when not in use.
- Turn off the key fob’s signal: Some newer fobs have a feature to disable their wireless transmission when not in use. Check your owner’s manual.
- Store keys away from entry points: Keep your fob far from windows and doors to make signal capture more difficult at home.
- Stay alert in public: Be aware of anyone standing unusually close to you or your vehicle, especially in crowded areas.
- Use physical deterrents: Steering wheel locks, wheel clamps, aftermarket alarms, and secondary immobilizers can slow thieves down or deter them entirely.
- Install a motion sensor or driveway alarm: Early alerts can give you time to respond before a theft occurs.
Relay attacks are not the only way modern cars are stolen! Read our article about Late Model Car Theft- “Car Hacking” to learn more. Also, see our guide on Layered Defense for Auto Theft Prevention for the most comprehensive list of theft prevention measures.
