Nissan suffered a data breach last November in a ransomware attack that exposed the Social Security numbers of thousands of former and current employees, the Japanese automaker said Wednesday.

Nissan’s U.S.-based subsidiary, Nissan North America, detailed the cyberattack in a May 15 letter to affected individuals. In the letter, Nissan North America said a bad actor attacked a company virtual private network and demanded payment. Nissan did not indicate whether it paid the ransom.

“[U]pon learning of the attack, Nissan promptly notified law enforcement and began taking immediate actions to investigate, contain and successfully terminate the threat,” the car maker said in the letter, adding that “Nissan worked very closely with external cybersecurity professionals experienced in handling these types of complex security incidents.”

Nissan told employees about the incident during a town hall meeting in December 2023, a month after the attack. The company also told staffers that it was launching an investigation and would notify employees privately if their personal information had been compromised. Nissan said it’s providing free identity theft protection services to impacted individuals for two years.