While most modern cars boast keyless entry and ignition systems to offer convenience, they also have an uncomfortable truth – they are vulnerable to ‘relay attacks’.
Here, we explore the world of relay attacks, explaining how they work and, more importantly, what you can do to protect your car from becoming a target.
What is a relay attack?
A relay attack is a sophisticated method employed by thieves to steal vehicles equipped with keyless entry systems.
These systems rely on a key fob that transmits a low-frequency radio signal to unlock the car.
In a relay attack, the criminal uses two devices: a relay amplifier – which is also known as an ‘emulator’ – and a signal interceptor.
- Signal interceptor: This device sits close to your home and captures the signal from your key fob
- Relay amplifier: This device amplifies the weak signal emitted by your key fob to fool the car into thinking that you and your fob are close to the vehicle.
Here’s how the car thieves carry out a relay attack:
- Signal interception: The thief positions the signal interceptor near your home (ideally, outside your window or front door) and the car key fob is probably close to the front door.
- Signal amplification: The interceptor captures the low-powered signal from your key fob. The relay amplifier, positioned near the car, then boosts the captured signal.
- Tricking the car: The amplified signal is transmitted to the car, tricking it into believing the key fob is nearby. This boosted signal unlocks the car and allows the thief to enter.
- Ignition bypass: Many keyless systems also allow engine starting without a physical key. In some cases, the thief may be able to exploit vulnerabilities in the car’s system to start the engine and drive away.
The entire process can be surprisingly quick and silent – it can take less than 20 seconds – leaving the owner completely unaware until it’s too late.
Why are relay attacks becoming more common?
The rise of keyless entry systems has, unfortunately, created an opportunity for tech-savvy criminals.
These systems offer convenience, but they often lack robust security measures.
Also, the equipment needed to carry out a relay attack can be readily bought online, making it a more accessible crime for thieves.
The impact on UK car owners
The Guardian reports that car thefts in England and Wales have reached the highest in a decade, soaring from 85,803 vehicles stolen in the year to March 2012 to a staggering 130,270 in the year to March 2023.
Car crime experts told the newspaper that the rise is down, in part, to the widespread adoption of keyless entry systems.
While keyless entry fobs with buttons first appeared in the 1980s, it wasn’t until a decade later that car manufacturers began incorporating keyless ignition systems, mainly for luxury vehicles.
The subsequent introduction of ‘smart key’ fobs, which automatically unlock the car when close by, has further exacerbated the problem.
How to prevent relay attacks
Here are several ways to protect your car from a relay attack:
- Faraday cage: Invest in a Faraday cage for your key fob. This is a metal box that blocks radio signals. When you’re not using the fob, store it in the cage, effectively preventing the signal from being captured.
- Signal blocking pouches: Signal-blocking pouches are another option. These pouches utilise materials that block radio waves and can be used to store your key fob when not in use.
- Park in a secure location: When possible, park your car in a well-lit garage or a secure car park. Avoid leaving it on the street, especially near your home, as this makes it easier for thieves to intercept the signal.
- Security software updates: Ensure your car’s software is up to date. Manufacturers sometimes release updates that address vulnerabilities in keyless entry systems. Keeping your software current can help improve security.
- Disable keyless entry (if possible): Some car manufacturers offer the option to disable the keyless entry function and revert to using a traditional key. This can be a drastic step, but it will eliminate the possibility of a relay attack. However, check with your manufacturer first, as disabling this feature might invalidate your car’s warranty.
Using a Ghost Immobiliser – a robust defence
While the tips mentioned above offer some level of protection, a more comprehensive solution is available in the form of a Ghost Immobiliser.
This security system works by creating a hidden layer of security on your car’s CAN (Controller Area Network) bus, the central communication system within the vehicle.
Here’s how a ghost immobiliser thwarts relay attacks:
- No signal interception needed: Unlike traditional key fobs, Ghost Immobilisers don’t rely on radio signals. Instead, they use a unique PIN code or a tag (depending on the model) to unlock and start the car. This eliminates the vulnerability of signal interception.
- CAN Bus security: The Ghost Immobiliser integrates seamlessly with your car’s CAN bus. Even if a thief gains entry via a relay attack, the car won’t start without the correct PIN or tag, rendering the stolen vehicle useless.
- Multiple authentication options: Modern Ghost Immobilisers offer various authentication methods such as PIN code entry through hidden buttons or a tag that needs to be placed near the steering wheel. This flexibility allows you to choose the method that best suits your needs and preferences.
- Customisable settings: Ghost Immobilisers can be customised to your specific requirements. For example, you can set the PIN code to a sequence that is difficult for thieves to guess. You can also choose whether to activate the immobiliser automatically when the car is parked or only when you manually arm it.
- Hidden installation: Ghost Immobilisers are typically installed in a concealed location within the car, making it difficult for thieves to detect or disable. This ensures that the system remains effective even if the thief manages to bypass other security measures.
How drivers can avoid a car relay attack
Relay attacks pose a significant threat to keyless entry cars but by understanding how these attacks work and taking proactive measures, you can significantly reduce the risk of your vehicle becoming a target.
Faraday cages, signal blocking pouches and secure parking practices are all valuable steps to consider.
However, for the ultimate protection, investing in a Ghost Immobiliser is highly recommended.
This advanced security system offers a robust defence against relay attacks and other forms of car theft and, by combining these measures, you can significantly enhance your car’s security and peace of mind.
