South Korean police said on Sunday that suspected North Korean hackers attacked joint military exercises between the United States and South Korea this week but were unable to obtain classified information.
And on Monday, South Korea and the US military plan to start the Ulchi Freedom Guardian 11-day summer exercise to improve their ability to counter North Korea's advanced nuclear and missile threats.
North Korea opposes such exercises on the grounds that they are preparations for an invasion of the United States and its ally South Korea.
The Nampo-do Police Department in Gyeonggi Province said in a statement that the hackers, who researchers believe are linked to a North Korean group called Kimsuki, carried out the hack by sending emails to South Korean contractors involved with the South Korean government. Korea. United States Joint War Offensive. simulation center.
"It has been confirmed that no military information has been stolen," the police said in a statement on Sunday.
North Korea has previously denied any involvement in cyberattacks.
Researchers said Kimsuky hackers have long used "spear phishing" messages to trick targets into providing passwords or clicking on attachments or links that contain malware.
Police said a joint investigation by South Korean police and the US military found that the IP addresses used in the hack matched those contained in a 2014 hack of a South Korean nuclear reactor operator.
At the time, South Korea accused North Korea of being behind the cyberattack.