According to CBS's 60 Minutes program two blackouts that affected millions of Brazilians in 2005 and again in 2007 were caused by hackers going after systems that control the power grid.
The spotlight has been turned on US defenses with Mike McConnell, a former Chief of US National Intelligence, saying that a similar attack on the US is likely imminent and that the US is unprepared for it.
For several years the US has been under cyber attack with the major government web sites coming under attack and the US command network for both Iraq and Afghanistan, CENTCOM, suffering a breach of unknown origin.
