Ohio’s Union County suffers ransomware attack impacting 45,000 people

A ransomware attack resulted in the theft of Social Security and financial data from Union County, Ohio, impacting 45,487 people.

A ransomware attack hit Union County, Ohio, and crooks stole Social Security and financial data. Officials notified 45,487 residents and staff after the security breach that occurred on May 18, 2025.

After discovering the security breach, Union County launched an investigation with the help of external cybersecurity experts.

Cybercriminals accessed the County’s network between May 6 and 18, 2025 and stole some data. By August 25, officials finished reviewing the breach and began notifying affected individuals.

“On May 18, 2025, the County detected ransomware on our computer network. As soon as we learned this, we immediately launched an investigation with assistance from nationally recognized third-party cybersecurity and data forensics consultants to secure our network and investigate the scope of the incident. We also alerted federal law enforcement.” reads the data breach notification letter sent to the impacted individuals and shared with the Maine General Attorney. “Through our investigation, we determined that the cyber criminals accessed our network from May 6, 2025 through May 18, 2025, and took some County data.”

Stolen data includes names, Social Security numbers, driver’s license numbers, financial account information, fingerprint data, medical information, passport numbers and more. 

At this time, no ransomware group has claimed responsibility for the attack.

Union County, Ohio is located in central Ohio, with Marysville as its county seat. In 2025, it has around 75,159 residents and is among Ohio’s fastest-growing counties. The area offers a mix of small towns and suburban communities, strong workforce, and high median income.

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Pierluigi Paganini

(SecurityAffairs – hacking, ransomware)

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