[11] The activities of the agency came to public attention in December 2014 when Sony Pictures canceled the opening of its movie The Interview after its computers had been hacked.
[7][10][15] North Korea has also been thought to have been responsible for infecting thousands of South Korean smartphones in 2013 with a malicious gaming application.
[14] The attacks on South Korea were allegedly conducted by a group then called DarkSeoul Gang and estimated by the computer security company Symantec to have only 10 to 50 members with a "unique" ability to infiltrate websites.
[5][6][16] According to a report by Reuters, Bureau 121 is staffed by some of North Korea's most talented computer experts and is run by the Korean military.
[23] A 2021 estimate suggested that there may be over 6,000 members in Bureau 121, with many of them operating in other countries, such as Belarus, China, India, Malaysia, and Russia.