TOKYO - Japan's government asked telecommunications companies to block access to a website publishing what was purported to be customer information stolen from GMO Internet Group Inc. as part of an extortion attempt before the site became inaccessible to the public, sources close to the matter said Thursday.
The Ministry of Internal Affairs and Communications made the written request Tuesday to industry groups representing telecom operators, including the Telecommunications Carriers Association, amid concerns that the information could spread further.
Chief Cabinet Secretary Minoru Kihara said Thursday that the government was "holding various exchanges with telecommunications operators" to prevent further damage.
Blocking access to the site, which could amount to a substantive infringement of the constitutionally guaranteed secrecy of communications, was apparently deemed necessary and acceptable as an emergency measure as the risk of privacy-related information spreading became real.
The website posted one person's personal information Tuesday and became inaccessible the following day, although that was not believed to have resulted from the blocking request.
GMO said Wednesday that the site became inaccessible following measures taken in cooperation with related parties.
The hacker believed to be behind a recently confirmed unauthorized access to GMO's foreign exchange trading service had warned in an online statement Tuesday that the personal data of more customers would be released daily.
GMO said Thursday that its internal response team had obtained information that could help identify the attacker and that it would submit it to police.
Forced blocking has recently drawn attention in Japan amid debate over its use against illegal overseas online casino websites. The measure is considered less effective against sites on the highly anonymous dark web.
