Union County, Ohio, discovered a ransomware attack on its computer network on May 18, 2025. Following the breach, the county immediately launched an investigation with the assistance of external cybersecurity and data forensics experts to secure its systems and determine the extent of the damage. They also contacted federal law enforcement to report the incident.
The investigation revealed that cybercriminals had infiltrated the county’s network between May 6 and May 18, 2025, and managed to exfiltrate a significant amount of data. By August 25, the review was complete, and officials began the process of notifying the 45,487 individuals whose personal information was compromised.
The stolen data is extensive and includes highly sensitive information such as names, Social Security numbers, driver’s license numbers, financial account details, medical information, and passport numbers. This broad scope of compromised data presents a substantial risk of identity theft and financial fraud for those affected.
While the investigation is ongoing, no specific ransomware group has publicly claimed responsibility for the attack. This lack of attribution can sometimes make it more difficult for law enforcement to track down the perpetrators.
Union County, with its seat in Marysville, is a rapidly growing area in central Ohio. With a population of around 75,159 in 2025, it’s known for its small towns, strong economy, and high median income. The attack on its digital infrastructure highlights that even prosperous, less-urban areas are not immune to the threats posed by sophisticated cybercriminals.
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