How Big Is North Korea’s Hacker Army?

Earlier today the South Korean Defence Ministry annou​nced that North Korea has an estimated 6,000 elite hackers working in the shadows to cause "physical and psychological paralysis." That's double the 2013 estimate by ministry officials.

Speculative remarks about the size and capabilities of North Korea's hacker army, known as Bureau 121, have fluctuated wildly in the wake of the Sony hacks that resulted in terabytes of employee data being leaked onto the internet.

North Korea was implicated in the hacks against Sony by the FBI on December 19th, 2014, less than a month after the first hack was perpetrated on November 22nd. Since then, the public's attention has turned to the mysterious Bureau 121.

Jang Se-yul, a North Korean who defected to the South six years ago, placed the size of Bureau 121 at a modest 1,800 hackers in Dece​mber. Another defector, Kim Hueng Kwang, estimate​d that the North's cyber warfare program has 3,000 members, citing an unverified government document he obtained in 2009. In 2013, South Korean Defense Minister Kim Kwan Jin also s​tated that North Korea employs 3,000 elite  hackers. Now, that number is 6,000.

Bureau 121 is said to operate in shadowy cells placed around the world, including one based in a hotel in China according to defec​tors, making venturing a guess as to its size a tricky endeavour.

Bureau 121's exact activities are as enigmatic and contested as its supposed size. The South Korean government previously placed the blame for a series of hacks that targeted financial institutions and other high-profile targets on Bureau 121.

However, a report by cyber security company Symantec placed the blame for those attacks on a well-organized group of between 10 and 50 hackers known as the "Dark Seoul Gang"—a far cry from the reports of Bureau 121's vast ranks touted by the South Korean government and North Korean defectors.

Bureau 121's involvement aside, skepticism regarding the FBI's publicly released evidence against North Korea has remained strong among independent security experts. However, the US government maintains North Korea's guilt in the hacks, citing classified evidence, and levied san​ctions against the nation.

The FBI declined Motherboard's request for comment on the veracity of the South Korean government's claims regarding the size of North Korea's cyber warfare unit.