Week 24, 2025 security incident report

YES24 ransomware infection halts book sales and ticket bookings

Impact: Website and app access and book purchases and ticket bookings halted; miscellaneous losses of 4.8 billion won

YES24 was infected with ransomware on 9 June 2025, cutting off access to its website and app and disrupting book purchases and performance ticket bookings. The company said its initial investigation had found no signs of major data leakage or loss, and police and the Personal Information Protection Commission (PIPC) launched investigations. After resuming some services, the company announced a compensation plan for all members, and it later emerged that it had paid the hackers in bitcoin and that its backup network had also been infected.

QuadMiner hacked as attackers claim source code theft and demand money

QuadMiner was hacked and received repeated monetary demands from the ransomware group NightSpire. The group claimed to have hacked an internal developer's MacBook and stolen the latest source code. QuadMiner acknowledged the hack and said there was no damage to customers.

Hacking of about 30 South Korean websites leaks over 110,000 personal records

110kImpact: More than 110,000 personal records

Hacking was confirmed at about 30 websites in South Korea. More than 110,000 personal records were leaked.

Korea Pharmaceutical Information Center exposes personal data of 7,669 members

7.7kImpact: IDs, names, phone numbers, email addresses and encrypted passwords of 7,669 members

The IDs, names, phone numbers, email addresses and encrypted passwords of 7,669 members were exposed in Q&A posts on the defunct website of the Korea Pharmaceutical Information Center. After confirming the exposure on 30 May 2025, the centre deleted the posts and reported it to the Personal Information Protection Commission (PIPC). As of 11 June, it was still investigating what had happened.

Merck service error exposes personal data of up to 108 people

108Impact: Personal information of up to 108 people

An error in Merck's new medication record management service exposed the personal information of up to 108 people to other users. An investigation found a problem in which different users accessing the service were treated as the same person, as well as a delay in notifying the leak. A penalty surcharge of 80 million won and an administrative fine were imposed for negligent data protection and late notification.

MG Community Credit Cooperatives customer data leaked

Impact: Customers' personal information

Customers' personal information was leaked from MG Community Credit Cooperatives (Saemaul Geumgo). It was confirmed that customers had not been aware of the leak.

United Natural Foods cyber-attack disrupts grocery supply

Impact: Disruption to operations and grocery supply, and forecast lost sales of up to $400 million

Whole Foods supplier United Natural Foods suffered a cyber-attack in June 2025 that disrupted its operations and grocery supply. The company took some systems offline, then worked on recovery and resumed order intake and shipments. In July, it forecast that lost sales from the attack could reach up to $400 million.

United Natural Foods hack disrupts grocery supply

Impact: Product shortages at some Whole Foods shops and forecast lost sales of hundreds of millions of dollars

United Natural Foods, a major distributor for Whole Foods, was hit by a cyber-attack that halted its systems and deliveries. Some Whole Foods shops experienced product shortages, and the company said in mid-June 2025 that recovery was under way. In July, it disclosed forecast lost sales from the attack and a revised annual earnings outlook.

WestJet cyber-attack exposes data of 1.2 million passengers

1.2mImpact: Personal information of 1.2 million passengers leaked

Canadian airline WestJet was hit by a cyber-attack in June 2025 that disrupted access to internal systems and customer services on its website and app. The company launched an investigation into the breach and began recovery efforts, after which the theft of passengers' personal information was confirmed. On 1 October, the number of people affected was reported to be 1.2 million passengers.

Over 4 billion personal records leaked in China, including Alipay and WeChat data

4bnImpact: More than 4 billion user records

More than 4 billion personal records, including Alipay- and WeChat-related information, were leaked in China. The leaked data included sensitive user records.

Microsoft email accounts of some Washington Post journalists compromised

Impact: Email accounts of some journalists compromised

The Microsoft email accounts of some Washington Post journalists were compromised in a cyber-attack. Journalists covering national security, economic policy and China were targeted, raising the possibility of foreign government involvement. The Washington Post is investigating the incident.