Charles Henderson loved his "awesome" convertible, particularly the fact that he could start, lock and unlock it remotely via his mobile phone.
It was one of the first connected cars that synchronise wirelessly with smartphones for entertainment and work purposes.
But after he sold the vehicle, he was astonished to discover that he could still control it using the associated smartphone app. "I could have found out where the car was, unlocked it remotely, started it and driven off with it," he tells the BBC.
Mr Henderson, from Austin, Texas, is global head of X-Force Red, IBM's offensive security group, so he knows a thing or two about security. He tests companies' defences, both physical and digital.
Original article: www.bbc.co.uk