Cars and trucks today are computers, and a new report overseen by Sen. Ed Markey, D-Mass., comes with a warning: As more vehicles have wireless connections, the data stored in them is vulnerable to stealing, hacking and the same invasions faced by any technical system today. automakers, including Ford, Toyota and General Motors, asking what the companies were doing to secure the technology in their vehicles from cyberattack and how they manage personal data stored in cars.