Relay Attack
A relay attack is a theft technique that extends the radio exchange between a vehicle and a nearby contactless key. The vehicle is deceived into treating a distant authorized key as if it were close enough for passive entry or start.
How it works
One device is placed near the vehicle and another near the key, often inside a home. The pair forwards messages between them. The attackers do not need to copy or decrypt the credential if the system accepts the relayed timing and distance.
Relay attacks mainly concern passive keyless entry and start systems that respond automatically to proximity. They are different from radio jamming, which prevents a lock command from reaching the car, and from key cloning, which creates another credential.
Reducing exposure
Protection depends on the vehicle and key design. Motion-sleeping fobs, secure distance measurement such as ultra-wideband, disabling passive entry, and storing a fob in an effective radio-shielding container can reduce exposure. A steering-wheel lock adds a visible mechanical barrier, but no single measure guarantees prevention.
Learn more
See Basic access technology for passive entry, digital-key technologies, backup methods, and broader access-system security. Police crime-prevention guidance also describes relay theft and practical precautions. Police guidance on keyless relay theft