Ransomware attack exposes data of nearly 46,000 in Union County, Ohio

Union County, Ohio, has disclosed that a ransomware attack compromised the personal information of 45,487 residents and staff, exposing sensitive records including Social Security numbers and financial data.

County officials detected the ransomware on May 18, 2025, and immediately launched an investigation with the support of third-party cybersecurity and data forensics experts. According to a breach notification letter filed with the Maine Attorney General’s Office, cybercriminals accessed the county’s computer network between May 6 and May 18, stealing files before the attack was contained. Federal law enforcement was also alerted.

The stolen data varied by individual but included names, Social Security numbers, driver’s license numbers, financial account details, fingerprint data, medical records, and passport numbers. Officials said they finished reviewing the scope of the breach by August 25, 2025, and began mailing notification letters to affected individuals soon after.

“At this time, we have no evidence that the information has been misused, but we encourage all affected individuals to remain vigilant,” the county stated in its letters to those impacted. No ransomware group has yet claimed responsibility for the attack.

Union County, located in central Ohio with Marysville as its county seat, is home to approximately 75,159 residents and is among the state’s fastest-growing counties. Known for its mix of small-town and suburban communities, the area has a strong workforce and a high median household income.

The county said it has implemented additional security measures to strengthen its systems and prevent similar incidents in the future. Impacted individuals are being advised to monitor their credit and financial accounts closely, and to take advantage of available fraud protection resources.