FILE - In this July 16, 2013 file photo, a woman walks by a sign at Cyber Terror Response Center of National Police Agency in Seoul, South Korea. Most North Koreans have never even seen the Internet. But the country Washington suspects is behind a devastating hack on Sony Pictures Entertainment has managed to orchestrate a string of crippling cyber infiltrations of South Korean computer systems in recent years, officials in Seoul believe, despite North Korea protesting innocence. (AP Photo/Ahn Young-joon, File)
SEOUL, South Korea — Most North Koreans have never seen the Internet. But the country Washington suspects is behind a devastating hack on Sony Pictures Entertainment has managed to orchestrate a string of crippling cyber infiltrations of South Korean computer systems in recent years, officials in Seoul believe, despite North Korea protesting innocence.
Experts say the Sony Pictures hack may be the costliest cyberattack ever inflicted on an American business. The fallout from the hack that exposed a trove of sensitive documents, and this week escalated to threats of terrorism, forced Sony to cancel release of the North Korean spoof movie "The Interview." The studio's reputation is in tatters as embarrassing revelations spill from tens of thousands of leaked emails and other company materials.
Despite widespread poverty, malnutrition and decades of crippling U.S.-led economic sanctions, Pyongyang has poured resources into training thousands of hackers who regularly target bitter rival Seoul.
A look at the country's suspected capabilities and where experts believe the authoritarian nation is heading with its cyber program:
NORTH KOREA'S CYBERARMY
South Korea's former spy chief and a North Korean defector put the number of professional hackers at between 1,000 and 3,000. These numbers from Seoul's intelligence agency in 2010 and a leaked North Korean government document from 2009, which contained an order from late leader Kim Jong Il, may be outdated. But they agree that North Korea trains hackers at top schools to launch attacks on cyberspace mostly targeted at South Korea.
Defector Kim Heung Kwang said he trained student hackers at a university in the industrial North Korean city of Hamhung for two decades before defecting in 2003. Hackers also are sent to study abroad in China and Russia.
In 2009, then-leader Kim Jong Il ordered Pyongyang's "cyber command" expanded to 3,000 hackers, Kim said, citing a North Korean government document that he obtained that year. The veracity of the document could not be independently confirmed.
Kim, who has lived in Seoul since 2004, believes that more have been recruited since then, and said some are based in China to infiltrate networks abroad.
Simon Choi, a senior security researcher at Seoul-based anti-virus company Hauri Inc., said North Korean hackers have honed their skills from various attacks in South Korea. Choi, who analyzes malicious codes from North Korea, said the country's skills have improved and it is able to disguise malware as harmless computer code.