A malware infection on one employee computer at Nippon Columbia Group (NCG) has put personal records held for karaoke operator Daiichi Kosho at risk. According to Daiichi Kosho's disclosure, customer data was temporarily stored on that computer. The company has not confirmed any actual data leak or resulting misuse, and says its own systems were not affected.
What Daiichi Kosho says was exposed
Daiichi Kosho puts the affected scope at 8,724,000 records in total. That breaks down into 8,631,000 customer records and 93,000 employee records. Each record may contain a full name, gender, date of birth, email address and telephone number.
These are approximate counts of records potentially exposed, not a confirmed count of unique people or stolen records.
Passwords are not part of the affected data, according to the company. It also says it has found no sign that loyalty points were used without authorization.
Daiichi Kosho describes itself as Japan's largest karaoke maker, with 521 venues nationwide, including the Big Echo chain. The customer data relates to these brands: BIG ECHO, MEGA BIG, Karaoke CLUB DAM, Banana Club, B-GARAGE and DK Dining.
Timeline and response
Daiichi Kosho says NCG discovered the malware infection between October 1 and 2, 2026 and isolated the computer from the network on October 2. NCG informed Daiichi Kosho on October 5, after investigating the affected scope. NCG reported that passwords and other authentication credentials had been reset; the cause, scope and possibility of data leakage remain under investigation.
Daiichi Kosho states that its own systems were not breached. The exposure sits entirely within the contractor's environment.
A later update, as described by BleepingComputer, added nothing further on whether data leaked. BleepingComputer found no public announcement from NCG and says it has contacted the company and is awaiting a reply.
What is still unknown
The reporting does not name the malware family, the way it reached the employee's computer, or any attacker or group. Whether data was actually stolen, leaked or sold is unconfirmed. What is established is the infection on one workstation and the scope of data that system could reach, as defined by Daiichi Kosho.
The two headline figures describe different scopes. About 8.6 million refers to customers alone (8,631,000), while the 8,724,000 total also includes the 93,000 employee records.
Guidance for customers
Daiichi Kosho advises customers to stay cautious given the potential risk. In practice, it recommends treating unsolicited email, SMS or phone contact with suspicion, particularly anything asking for payments or for sensitive personal or financial information. The exposed fields are enough to make such messages look personalized, so a message that uses a correct name or birth date is not proof of legitimacy.
