Answer by Mikko Hypponen, CRO at F-Secure, on Quora:

Smartphones are actually much more secure than computers. They have fairly bad privacy problems, but from a security point of view, they are clearly superior to computers. This is mostly because of the app store model, as you can’t just run random programs.

We have seen security problems and malware on smartphones, but they are typically related to users sideloading apps from third party sources or rooting their devices by themselves.

IoT headaches have already started. One thing we are forecasting is that home IoT devices will more and more become “the way in”, or the weak link in the chain. Attackers might not be able to break into your home network via your computers, but they might be able to break in via your IoT coffee machine.And, one day we will see IoT ransomware. Imagine ransomware on your smart car: “Pay 2 Bitcoins if you want to pick up the kids from the daycare in time.”

Source : http://www.forbes.com/sites/quora/2016/12/27/the-internet-of-things-is-coming-and-its-bringing-security-headaches/#3d13bc17d468