The City of Columbus, Ohios state capital, has confirmed that hackers stole the personal data of 500,000 residents during a July ransomware attack.In a filing with Maines attorney general, Columbus confirmed that a foreign cyber threat actor compromised its network to access information including residents names, dates of birth, addresses, identification documents, Social Security numbers, and bank account details.The city, which is the most populous in Ohio with approximately 900,000 residents, says around half a million individuals were affected, though it has not confirmed the exact number of victims.The regulatory filing comes after Columbus was the target of a ransomware attack on July 18 of this year, which the city claimed to have thwarted by disconnecting its network from the internet.Rhysida, the ransomware gang responsible for last years British Library cyberattack, claimed responsibility for the attack against Columbus in August. At the time, the gang said it had stolen 6.5 terabytes of data from the city in Ohio including databases, internal logins and passwords of employees, a full dump of servers with emergency services applications of the city and access from city video cameras, according to local news reports.Rhysida asked for 30 bitcoin, around $1.9 million at the time of the cyberattack, as payment for the stolen data.Two weeks after the cyberattack, Columbus mayor Andrew Ginther told the public the stolen data was likely corrupted and unusable.The accuracy of Ginthers statement was thrown into doubt the following day after David Leroy Ross, a cybersecurity researcher also known as Connor Goodwolf, revealed that the personal information of hundreds of thousands of Columbus residents had been listed on the dark web.In September, Columbus sued Ross, alleging that was threatening to share the Citys stolen data with third parties who would otherwise have no readily available means by which to obtain the Citys stolen data. A judge filed a temporary restraining order against Ross, preventing him from accessing the stolen data.In a listing on its leak site, seen by TechCrunch on Monday, Rhysida claims to have uploaded 3.1 terabytes of unsold data stolen from Columbus, amounting to more than 250,000 files.