Two years for teen 'cyber terrorist' who targeted US officials
Kane Gamble, 18, targeted CIA, FBI and US Department of Justice databases from his bedroom in Leicestershire.
The Old Bailey was told Gamble, who has admitted a number of charges, damaged the "effectiveness" of the wider law enforcement community.
He will serve two years at a youth detention centre.
His defence said he was "naive" and never meant to "harm" any individuals.
But the judge, Mr Justice Haddon-Cave said Gamble ran a "campaign of cyber terrorism".
Gamble obtained "extremely sensitive" documents on military and intelligence operations in Iraq and Afghanistan, the court was told.