"Elements of the OSD unclassified email system were taken offline yesterday afternoon, due to a detected penetration," said Secretary of Defense Robert Gates, according to a transcript of the event published by the Defense Department. "We obviously have redundant systems in place, and there is no anticipated adverse impact on ongoing operations. There will be some administrative disruptions and personal inconveniences."
Gates said that the incursion was still being investigated and that the Pentagon repels "perhaps hundreds of attacks a day."
Speculations as to who instigated the attacks abound. According to officials in the Navy's Network Warfare Command unit who are quoted in an article published last year, one of the most significant security threats faced by the U.S. military comes from China.
But there is always the possibility that it could be a lowly computer nerd working in his mother's basement, such as Gary McKinnon, the British hacker who in 2001 and 2002 infiltrated almost 100 military servers while looking for evidence of a UFO cover-up and alien propulsion technology. McKinnon now faces extradition to the US.