Japan asked China to help probe a cyberattack earlier this year on the computer system of Mitsubishi Heavy Industries Ltd., government sources said.
The late September request was made because the cyberattack on the major defense contractor was suspected to have originated in China, the sources said Saturday.
China said in its reply it would contact the relevant authorities, but there has been little progress since, leaving the investigation at a standstill, they said.
After its own investigation, Mitsubishi Heavy said viruses had infected its in-house servers and computers in mid-August but there was no sign important defense-related data was taken.
Soon after the attack, MHI filed a complaint with the Tokyo Metropolitan Police Department, which came across information that pointed to the viruses coming from somewhere in China, the sources said.
The government of Prime Minister Yoshihiko Noda is studying whether he should bring up the subject at a meeting with Chinese President Hu Jintao and other senior officials when he visits China next month, they said.
With China repelling suspicions raised in Japan about the attacks coming from hackers in China, the chances of Noda gaining Beijing’s cooperation are slim, observers say.