Embedded Systems poses a new level of security threats

It is possible to see the actual working of mechanical devices. They can not contain malwares.

Embedded systems have a firmware and can have many hidden codes that can be exploited and all "soft" limits can likely be overridden by software commands. Increasing use of connectivity increases the threat exponentially.

http://searchsecurity.techtarget.com...id-rise-of-IoT

Connected appliance embedded system used to facilitate crime
http://www.businessinsider.com/hacke...inesses-2014-1

Car hijacked by connecting to embedded system wirelessly
http://www.wired.com/2015/07/hackers...-jeep-highway/

Particular threats to industrial systems:
http://blog.serversilo.com/index.php...l-internet-ge/