Japan has revealed that its defence ministry suffered a serious cyber attack in September.
The Japanese Ministry of Defense has suffered a very serious cyber attack that may have been launched from a foreign state agency and could cause the leakage of sensitive information, ministry sources say.
The purpose of the attack, which was carried out in September and has been now revealed, was the Ministry's Defense Information Infrastructure, an internal network connecting the different Japanese Self-Defense Forces bases, the sources told local news agency Kyodo.
The attack was described as "very serious" and said to be executed by "highly-skilled" agents who were likely part of certain foreign state agency due to their high-level sophistication.
Japanese authorities are now working to assess the damages and the amount of data that could have been leaked, as well as repairing security breaches, the government source added.
The attack occurred through unauthorised online access to National Defense Academy and the National Defense Medical College computers, which were used as "bridges" to penetrate the internal network of Japanese bases.
As a result of the incident, the Self Defense Forces temporarily prohibited all employees from using the internet.
The "hacking" of a system with supposedly high protection against cyber attacks has once again exposed the vulnerability of computers used by state entities and Japanese companies.
In recent years, there have been several similar incidents that resulted in massive leakages of personal data, although the case reported on Monday is one of the most serious affecting the classified government information.
Last June, the Government of Tokyo launched a strategy to increase the protection of public bodies against cyber attacks, in line with the declaration on such issue adopted by the G7 in the summit held in late May in Ise-Shima, Japan.