Complexity was called "the worst enemy of security," as a connected car could have "approximately 100 million lines of code," compared to 8 million for an F-35 fighter jet. There has been a dramatic increase in Electronic Computing Units, with some high-end vehicles currently having about 100 ECUs. There has also been a rise in the diversity of in-vehicle systems which provide both luxury and critical features.
Connectivity was called a "double-edged sword" since adding cars to the Internet of Things will continue to make vehicles "a more accessible and more attractive target to adversaries."
BI Intelligence estimated 75% of 92 million cars shipped globally in 2020 will be "connected cars." VDC Research claimed, "Connected vehicles are an attack waiting to happen. The average new car in 2015 contained more than 30 microprocessors, and the cybersecurity of those embedded systems is severely challenged by in-vehicle Internet connectivity." In 2014, only 2% of microprocessors in cars had hardware security features, VDC's report (pdf) claimed.