Japan's finance ministry shut down part of its computer system Tuesday afternoon after detecting an outside intruder on its website, officials said, a development that may raise fresh security concerns over the vulnerability of the country's data network.
The intruder, whose identity isn't clear yet, unnecessarily added information to part of the ministry's website containing public information about Japan's national properties, a ministry official told Dow Jones Newswires.
That information has already been removed, and the MOF has confirmed that the intruder made "no changes to the content or any data" of the web site, the official said. No classified information has been stolen, he added.
The Japanese Cabinet Office's security center is likely to lead investigation into the problem, the official said.
The incident was nothing serious and doesn't mean that the MOF's computer system is weak against attempts by outsiders to revise the content of the ministry web site, the official said. It is not clear when the ministry will put the part of the system now being shut down back in operation, but it shouldn't take a week, he said.
The system problems follow a posting by hacker group Anonymous on its website in which it alludes to launching a cyber-attack in retaliation for an amendment to the nation's copyright law.
"To the government of Japan and the Recording Industry Association of Japan, you can now expect us the same way we have come to expect you in violating our basic rights to privacy and to an open internet," the post read.