Anyone with a computer and an Internet connection can launch a cyber "attack," even though the skills and tools needed to do real damage are still in short supply.

The Internet was not built to be secure and will not become secure anytime soon. Networks are vulnerable. This explains why cyber-espionage and fraud are so easy. Economies depend on the Internet, and a growing number of services and devices are connected to it, making it an irresistible target.

Crash the computers that run these systems and things stop. Power grids, financial networks, communications, public utilities and transportation systems are all targets for cyber-attacks.