BMW cars made since 2006 carry an on-board computer that controls the engine, and makes sure everything is working OK. Also, it controls the electronic key, which communicates with the computer via radio signals and can start the car. This on-board computer also has a very convenient feature, it can program a new key for you, say you lost your keys.

In other words the computer has access to your vehicle, and now, thieves have figured out a way to hack into the car's computer, and take full control of the car. They use a device together with a blank key, to break into the computer, and program the blank key to take control of the vehicle. All is accomplished in a little over 3 minutes. What is even worst, both blank keys and the hacking device can be bought on the Internet. 

The problem is bad, and remains unsolved since it was first reported back in 2011. It is so bad police in London were placing leaflets in BMW's to warn people that their vehicle could be targeted. 

 A BMW spokesperson clarified that not all of their recent models where affected. "...after extensive research we are clear that none of our latest models - new 3 Series, 5 Series, 6 Series and 7 Series - nor any other BMW built after September 2011 can be stolen using the method you have highlighted". But this still leaves quite a few models out there vulnerable.

So, what can you do? First, bear in mind that not only BMW's are affected, as many other brands carry these on-board computers, so first inquire with your company if your car in vulnerable to this attack. If it is, here is what BMW recommended:

"When using remote locking, ensure the car has actually locked by checking a door.
Be careful with your keys and who you give them to (e.g. valet parking). There is a risk that they could be cloned.
Whereever possible park your car out of sight, in a locked garage or under the cover of CCTV cameras. 
We recommend servicing your BMW at dealerships capable of providing software updates (e.g. authorised BMW Dealerships) on a regular basis to give the opportunity of further enhancing theft protection."