The one mistake with keys making you an easy car theft target
Shopping trips have become a hunting ground for a new breed of car thief. While you’re loading groceries into your boot or wheeling a trolley back to the store, criminals could be silently stealing the signal from your car keys to drive away with your vehicle.
This sophisticated theft method, known as a relay attack, doesn’t require breaking windows or hot-wiring engines. Instead, thieves use readily available technology to capture and amplify the signal from keyless entry fobs, allowing them to unlock and start cars within seconds.
Kazimieras Urbonas, Supplier Excellence Manager at Ovoko, one of Europe’s largest online marketplaces for used car parts, has seen the devastating impact of these thefts on car owners across the continent.
The thefts are happening so quickly that many victims don’t realise their car is gone until they return from shopping. To help you, he shares his insights below.
How relay attacks work in supermarket car parks
The relay method is alarmingly simple yet devastatingly effective. Two thieves work as a team, positioning themselves strategically around busy car parks where shoppers are distracted and vulnerable.
The first criminal stands near your car with a device that can detect key fob signals from up to 100 metres away. Meanwhile, their partner positions themselves closer to you, perhaps pretending to shop or loitering near the store entrance.
When you walk near your vehicle with your keys in your pocket or bag, the device picks up the constant signal that keyless entry systems transmit. This signal gets relayed instantly to the second device by the car, which tricks the vehicle into thinking the genuine key fob is right beside it.
The entire process takes less than 60 seconds. While you’re still loading shopping or returning your trolley, thieves can unlock your car, start the engine, and drive away without setting off any alarms.
Why keyless entry makes you a target
Modern keyless entry systems are designed for convenience, constantly broadcasting a low-frequency signal that allows you to unlock your car without pressing buttons. However, this convenience creates a security weakness that criminals exploit.
Your key fob is essentially having a conversation with your car at all times. Thieves simply eavesdrop on that conversation and repeat it back to your vehicle.
The problem becomes worse in supermarket environments where several factors increase your vulnerability:
- Walking to or from your car – Standing close to your vehicle with keys in your pocket or bag makes signal capture easier
- Shopping inside the store – Thieves can position themselves strategically, with one near your parked car and another closer to the store entrance to capture your key signal as you move around
- Distracted behaviour – Being focused on children, shopping lists, or phone calls means you’re less likely to notice suspicious individuals following your movements or loitering near your vehicle when you return
- High footfall areas – Busy car parks provide cover for thieves to blend in while they position their equipment and wait for opportunities
Four ways to protect yourself
Urbonas shares four ways you can help to avoid being a target.
1) Use a signal-blocking pouch at all times
Invest in a Faraday pouch or signal-blocking wallet that completely blocks radio frequencies. Keep your keys inside this pouch from the moment you leave home until you return, even while walking around shops.
2) Keep keys away from your car when outside
Never stand directly beside your vehicle while holding unprotected keys. If you need to load shopping, place keys in a signal-blocking pouch first, or ask a family member to hold them at a distance.
3) Store keys in metal containers at home
When parked at home, keep key fobs in metal tins or your fridge, which naturally block radio signals. Avoid leaving keys near front doors, windows, or anywhere close to where your car is parked.
4) Double-check your car is actually locked
After using keyless locking, physically test door handles to confirm the vehicle is secure. Some relay devices can prevent the locking signal from working properly.
These simple steps cost very little but can save you thousands in insurance claims and the hassle of losing your vehicle.
Prevention is straightforward and affordable
Supermarket car parks have become prime hunting grounds for relay attacks because they offer everything criminals need: high footfall, distracted victims, and plenty of escape routes. Shoppers are focused on their groceries and getting home, which makes them easy targets.
From our perspective in the automotive parts industry, we have seen the aftermath of these thefts. The speed and simplicity of relay attacks means traditional security measures like car alarms can be completely bypassed.
What concerns me most is how accessible this technology has become. The devices can be purchased online for under £100, meaning almost anyone can become a car thief overnight.
The good news is that prevention is straightforward and affordable. A signal-blocking pouch costs less than £20 and provides complete protection. Compare that to losing your car, and it’s an investment that pays for itself immediately.
Ovoko is one of Europe’s largest online marketplaces for used car parts, connecting over 4,000 auto dismantlers, recyclers, and sellers with car dealers, mechanics, and enthusiasts. With more than 23 million parts available, Ovoko offers fast delivery across Europe, a 14-day money-back guarantee, and tools that help scrapyards go digital.The one mistake with keys making you easy car theft target
