As the U.S. readies to publicly point the finger at North Korea for the much publicized Sony Hack last month, details are coming out about North Korea’s elite cyber unit known as Bureau 121. This cyber-warrior unit reportedly has 1800 agents, placed in multiple locations throughout the globe with one mission, hack into and disrupt western interests.

This unit of shadow warriors has been wreaking havoc in South Korea since last year. In March and June 2013, Bureau 121 is believed to be responsible for the event known as “dark Seoul,” In a massive cyber-attack, South Korean banks were brought to their knees as servers were jammed and ATM’s across the country were taken out of service for days. There was also a cyber-attack on South Korean media outlets, reportedly some TV stations were knocked off the air.

North Korea denied any involvement with the “dark Seoul” cyber-attack, just as they have in the hack on Sony Pictures. North Korea’s Government did however, praise the hack on Sony Pictures calling it a “righteous deed.”

It is believed North Korea was responsible for the Hack into Sony Pictures in retaliation for it’s movie The Interview. In the movie, reporters are recruited by the CIA to assassinate North Korean dictator Kim Jong Un. In response to the hack, and subsequent threats of violence at movie theatres, Sony decided not to release the film.

Defectors from the North Korea have said, Bureau 121 has some of the most talented and well trained computer experts. Bureau 121 is reported to be part of North Korea’s, General Bureau of Reconnaissance.

In a CNN interview, Jang Se-yul, a North Korean cyber expert who defected to the south seven years ago, revealed details into North Korea’s cyber force. Military hackers are handpicked, some as young as 17, and trained at North Korea’s Military College for computer science, known as the University of Automation. These cyber-warriors are among the most talented, and rewarded people in North Korea.

North Korea, one of the world’s poorest countries, with a young dictator in power, has largely been underestimated by the west for its technological might. The internet is only utilized by government officials. North Korean citizens are only allowed to use an “intranet,” this limits them to only accessing government approved propaganda sites or government controlled media.

The ability to wage cyber war is relatively cheap in comparison with traditional warfare. “For them, the strongest weapon is cyber,” Jang said. “This silent war — the cyber-war — has already begun without a single bullet fired.”

The cyber-attack on Sony has raised serious questions about cyber security at important government agencies and  to critical infrastructure in the U.S. “With the Sony collapse, America has lost its first cyber-war. This is a very, very dangerous precedent,” former Republican House of Representatives speaker Newt Gingrich tweeted.

“It’s remarkable that a country like North Korea can have that capability, if they’re able to disrupt a film, you can imagine what they are attempting to do to our national defense capabilities,” Senator John McCain, R-AZ, told reporters Thursday. Senator McCain also said cyber security will be one of the first things addressed when the Senate Armed services Committee reconvenes in January.