Online attack caused City Blackout says CIA

In the same week that the FBI issued a warning about the online dangers of Vishing, the US Central Intelligence Agency, has made public the fat that hackers have successfully build an attack that has disrupted "power equipment" and literally shut down cities, though none of them were in the United states.

In this example of cyber-attack, CIA senior analyst Tom Donahue, said that the organisation has collected evidence of blackmailing in order to prevent further disruptions.

"We have information, from multiple regions outside the US, of cyber-intrusions into utilities, followed by extortion demands," said Donahue. "We suspect, but cannot confirm, that some of these attackers had the benefit of inside knowledge."

One possible scenario could be that the hackers had successfully compromised a user's computer through an infected email or website.

Distributed Denial of Service that affects popular - and cash-rich - online retailers has been an issue that has all but disappeared from the web as vendors stepped up and devised smarter and more effective ways of tackling DDoS attacks.