The attack reportedly took place in September.
The attack reportedly took place in September.

Japanese Defense Ministry and Self-Defense Force (SDF) was targeted in September by a sophisticated cyberattack, according to sources cited by The Japan Times.

Defense officials were not making any public comment confirming the attack, with Deputy Chief Cabinet Secretary Koichi Hagiuda refusing to comment on the situation during a November 8 news conference. However, the news organization cited a senior SDF official who called the alleged attack “a very serious situation.”

Other sources said the attack struck the Japanese Defense Information Infrastructure, which connects SDF facilities, and gave unauthorized access to computers in the National Defense Academy and the National Defense Medical College. This allowed the hackers to also enter the primary SDF computer system, The Japan Times wrote.

No group or nation-state was named or has taken credit for the attack.