Payment software ran a vulnerable log4j version
https://www.bleepingcomputer.com/news/security/fintech-firm-hit-by-log4j-hack-refuses-to-pay-5-million-ransom/
One of the largest Vietnamese crypto trading platforms, ONUS, recently suffered a cyber attack on its payment system running a vulnerable Log4j version.
Soon enough, threat actors approached ONUS to extort a $5 million sum and threatened to publish the customer data should ONUS refuse to comply.