TOKYO: Chinese military hackers have breached Japan’s “most sensitive computer systems,” the classified defense networks of the Japanese Defense Ministry, The Washington Post reported in its online edition Monday.

The U.S. National Security Agency discovered the penetration by the People’s Liberation Army hackers in autumn 2020 and informed Japanese government officials about it, according to the newspaper.

Tokyo took steps to strengthen its networks, the paper said. Still, they are not sufficiently secure, it added, quoting U.S. officials as saying that this could impede greater intelligence sharing between the U.S. Defense Department and the Japanese ministry.

The Chinese penetration was “one of the most damaging hacks” in Japan’s modern history, with a former U.S. military official calling the cybersecurity breach “shockingly bad,” the paper said.

According to the report, Gen. Paul Nakasone, head of the NSA and U.S. Cyber Command, and Matthew Pottinger, White House deputy national security adviser at the time, visited Tokyo and directly briefed the defense minister, who, out of serious concern, made arrangements for them to directly alert the prime minister.

After Joe Biden replaced Donald Trump as U.S. president, Defense Secretary Lloyd Austin indicated to Tokyo that enhanced data-sharing to enable advanced military operations could be slowed unless Japan improves its network security, the newspaper reported.

In autumn 2021, however, Washington “uncovered fresh information that reinforced the severity of China’s breach of Tokyo’s defense systems and that Japan was not making much progress in sealing it,” according to the newspaper.

In November 2021, Anne Neuberger, deputy national security adviser for cyber, visited Tokyo and met with top military, intelligence and diplomatic officials, the paper said.

Neuberger did not explicitly tell the Japanese side how Washington knew about the Chinese compromise, according to the paper. It also that the Japanese government “knew that the United States spies on partners.”

JIJI Press