Half the cars broken into in London last year were hacked, not forced open, according to the Met Police.
A Sky News investigation said that thieves were regularly using high-tech devices to access cars with electric locks.
These devices were originally intended for locksmiths to get into cars without a key, but can have devastating consequences in the wrong hands. The gadgets are able to spoof the radio frequencies sent out by key fobs, and if they find the right one the door will simply open.
Sky said that it is possible to hack any of 50 low-powered computers in a modern car in less than 10 seconds.
Here's a paper looking at how the attacks work, and what can be done.
There are also various videos online which apparently show how to hack key fobs. Underneath one video a commenter asks, tongue in cheek, "do they have the frequencies for Lamborghinis?"
The Metropolitan Police apparently confirmed that the trend is an increasing threat to vehicles in the capital - echoing previous advice issued in recent years that hacked key fobs could give easy access to vehicles.
"Recent analysis of crime data suggests that almost half the total number of vehicles stolen in London are taken using this method, which can affect all manufacturers," the Met told Sky News.
"High-end vehicles are becoming more and more sophisticated. In turn so are criminals.
"Some organised criminals have access to technology that avoids the need to (physically break in). Vehicles are becoming more technologically advanced and the criminals are becoming more savvy towards that technology and they will develop."
On the other side of the debate, however, recent studies have suggested that while modern cars can be hacked, the chances of it actually happening are relatively slim - especially if it's a question of doing anything other than just getting inside. Manufacturers say they are aware of the potential risk and are working on new security systems which are less vulnerable.