From a newly released GAO report:
Modern vehicles contain multiple interfaces—connections between the vehicle and external networks—that leave vehicle systems, including safety-critical systems, such as braking and steering, vulnerable to cyberattacks. Researchers have shown that these interfaces—if not properly secured—can be exploited through direct, physical access to a vehicle, as well as remotely through short-range and long-range wireless channels. For example, researchers have shown that attackers could compromise vulnerabilities in the short-range wireless connections to vehicles’ Bluetooth units—which enable hands-free cell phone use—to gain access to in-vehicle networks, to take control over safety-critical functions such as the brakes. Among the interfaces that can be exploited through direct access, most stakeholders we spoke with expressed concerns about the statutorily mandated on-board diagnostics port, which provides access to a broad range of vehicle systems for emissions and diagnostic testing purposes. However, the majority of selected industry stakeholders we spoke with (23 out of 32) agreed that wireless attacks, such as those exploiting vulnerabilities in vehicles’ built-in cellular-calling capabilities, would pose the largest risk to passenger safety.
Full report (61 pp., pdf):
VEHICLE CYBERSECURITY: DOT and Industry Have Efforts Under Way, but DOT Needs to Define Its Role in Responding to a Real-world Attack
GAO-16-350: Published: Mar 24, 2016. Publicly Released: Apr 25, 2016