Talk about sloppy US intelligence: A British 15-year-old managed to access top secret US intelligence on Afghanistan and Iran by posing as former CIA chief John Brennan.

Kane Gamble, now 18, was able to gain access to US plans of intelligence operations in Afghanistan and Iran by pretending he was former CIA chief John Brennan, all while Gamble was just 15.

According to a report by the Telegraph, the teenager never left his bedroom in Leicestershire to conduct his hacking operations. What's more interesting, he didn't even technically hack into US intel systems, but rather used "social engineering," or manipulating people into doing what one needs done.

"The teenager persuaded call handlers at an internet giant that he was John Brennan, the then-director of the CIA, to gain access to his computers, and at an FBI helpdesk that he was Mark Giuliano, then the agency's Deputy Director, to re-gain access to an intelligence database," the Telegraph reports.

He also reportedly targeted US Secretary of Homeland Security chief Jeh Johnson and US President Barack Obama's Director of National Intelligence, James Clapper.

​After gaining access to secure computers, Gamble used the personal information to taunt his victims online, releasing personal information, bombarding them with calls and messages, and even downloading pornography onto their computers while taking control of their iPads and TV screens.

Gamble is a founder of a group calling themselves "Crackas With Attitude" (CWA), often mistakenly referred to as hackers, while in reality the group relies on social engineering.

"It all started by me getting more and more annoyed about how corrupt and cold-blooded the US Government are so I decided to do something about it," Gamble told journalists.

During an increasingly elaborate imposter operation, Gamble gained access to Brennan's Verizon internet account, then his AOL account and eventually Gamble was able to access Brennan's emails, contacts, iCloud storage account and his wife's iPad — all remotely.

"He accessed some extremely sensitive accounts referring to, among other things, military operations and intelligence operations in Afghanistan and Iran," prosecutor John Lloyd-Jones said.

Aside from Brennan, Gamble used the same techniques to gain access to the personal communications of Avril Haines, the White House deputy national security adviser; FBI Special Agent Amy Hess and Vonna Weir Heaton, a former intelligence executive with the US National Geospatial Intelligence Agency. In each case, Gamble succeeded in posing as people of very different age groups and even different genders.

According to the Telegraph, at one point Gamble considered not sharing any more information "because it put lives at risk, but then [he] thought: [the US government is] killing innocent people every day."

The date for Gamble's sentence is not yet set, although it is known that he has pleaded guilty on ten offences under the computer misuse act.