The communications ministry has asked internet providers to block access to an attacker-run website that carried what is believed to be personal data belonging to GMO Internet customers, the Asahi Shimbun, Yomiuri Shimbun, Nikkei and other outlets reported on October 29.
The ministry sent the request in a document dated October 27, passing it to companies through four telecommunications industry bodies including the Telecommunications Carriers Association, according to the reports.
Blocking — forcing every user's connection to a site to be cut — requires providers to know where all of their customers are connecting, which risks infringing on the secrecy of communications guaranteed by the constitution. The request rests on an administrative document, not a law.
Ministry cites risk of secondary harm
According to the Yomiuri Shimbun, the ministry's request said there is a realistic risk that misuse of the information will spread secondary harm, and asked providers to cut off the site carrying it "in light of the magnitude of this case's social impact." An executive at a major carrier said deciding whether to comply is difficult, the Yomiuri reported.
Carriers have not disclosed whether they actually blocked the site, according to Jiji Press and the Yomiuri. Chief Cabinet Secretary Minoru Kihara told a morning press conference on October 29 that the government is having "various exchanges" with providers, and declined to answer on specific measures because the matter is still unfolding.
Site went offline before any block
GMO said on October 28 that it had confirmed the suspension of the attacker's domain, including mirror sites. The Nikkei reported the view that the site became inaccessible and that blocking was ultimately never triggered.