TOKYO - Japanese internet service provider GMO Internet Group Inc., hit by a cyberattack, said Wednesday that a website containing what a hacker claimed was customer information has become inaccessible following measures taken in cooperation with related parties.
GMO said, "We have confirmed that the offender's website domain has been taken down." A hacker believed to be behind a recently confirmed unauthorized access incident involving GMO's foreign exchange trading service disclosed some customer information Tuesday after the company failed to respond to a ransom demand.
If the launch of another such website is confirmed, GMO will immediately take steps to make it inaccessible, it added.
The customer whose information is believed to have been posted on the website is under the protection of the Metropolitan Police Department due to safety concerns, an investigative source revealed Wednesday.
The person told investigators that the personal information posted on the website is "partially correct and partially wrong," according to the source.
The police have also asked GMO to assess the extent of the damage as they investigate the incident as a suspected violation of the law prohibiting unauthorized computer access.
The unauthorized access targeted the Onamae.com Desktop Cloud service. An investigation following a customer inquiry confirmed on Oct. 20 that an unauthorized program had been installed by a third party in the server environments of some customers.
GMO said late Monday that the hacker threatened to disclose customer information and to conduct a ransomware attack at noon Tuesday. A statement from the hacker and information linked to what it claims to be one GMO customer were posted online on Tuesday.
The statement also warned that personal data of customers would be released daily.
Japan Airlines is among the latest Japanese companies hit in a spate of unauthorized access incidents, saying Wednesday that around 92,000 customer records may have been leaked, including passport numbers and nationalities of approximately 2,000 customers.
Traces of external access showed that reservation data from Aug. 10, 2023, to Sept. 23, 2026, may have been compromised, it said.
Amadeus IT Group, S.A., which provides a passenger service system integrating flight reservations, ticketing and check-in procedures, informed JAL and Japan Transocean Air of the suspected data leak.
Amadeus has completed the necessary security measures, and there is no evidence so far that any customer information has been misused, JAL said.
