Insurance giant Aflac suffered a cyberattack potentially exposing Social Security numbers, insurance claims, and health data, marking the largest breach yet in a recent wave targeting the US insurance industry.

The hacks, also reported by Erie Insurance and Philadelphia Insurance Companies, are linked to the cybercrime group Scattered Spider, known for using social engineering—posing as tech support—to infiltrate networks quickly.

Aflac stopped the intrusion within hours and says no ransomware was deployed, but the breach’s full impact remains unclear, CNN has reported.

Experts warn that Scattered Spider’s rapid, widespread attacks pose a serious ongoing threat to American businesses.

Written by B.C. Begley