A cyber attack on Japan's biggest defense contractor likely netted military data on warplanes and information on nuclear power plants, the Asahi newspaper reported Monday, as pressure mounts on Japan to bolster cyber security after the attack came to light in August.
It remains unclear whether the military data from Mitsubishi Heavy Industries Ltd, including information on warplanes, helicopters and other equipment ordered by Japan's Defense Ministry, is deemed sensitive defense information, the Asahi said, citing a source close to the matter.
A Japanese defense ministry official said, that as of now, the ministry is not aware of any leaks of information classified as defense secrets.
Mitsubishi Heavy spokesman Hideo Ikuno declined to comment on the matter. "The issue is currently under investigation and I cannot comment on it," he said.
Mitsubishi Heavy, Japan's biggest weapons supplier, said last month that network information such as IP addresses may have leaked but that it had so far not confirmed any leaks of data on its products or technologies.
More than 80 computers or servers were found to have been infected by viruses, and checks on dozens of other servers in Japan showed that there were indications of leaks of military and nuclear power plant data, the Asahi reported.
It is highly likely that someone went in to steal the data, Asahi said, citing the source.
Mitsubishi Heavy, a partner with Boeing in weapons production, delayed reporting the incident, which became publicly known in August, in a possible violation of its military supply contracts.
Rivals IHI Corp and Kawasaki Heavy Industries have also said they have received suspicious e-mails, while a contractor to Mitsubishi Heavy is checking whether there had been a breach of sensitive data.
Japan is moving to strengthen its cyber security in line with calls from Washington, and will set up Tuesday a framework for sharing hacking information among governmental and private institutions, the Nikkei business daily reported on Monday.
Mitsubishi Heavy, IHI and Kawasaki Heavy Industries, as well as Toshiba Corp, Hitachi Ltd, Fujitsu Ltd, NEC and others, will take part in the framework, the Nikkei said, without citing sources.