Hackers broke into the systems of an Ohio hospital last month raising fears that the personal details of up to 230,000 patients or their family members, and banking information on around 12,000 financial donors, might have been compromised.
News of the attack came after Akron Children's Hospital began notifying families last week, around seven weeks after the security breach was identified.
The attack came as the hospital upgraded its systems. It's unclear whether or not data obtained by the hackers was subsequently abused to conduct ID theft or other scams.
In a statement on the attack, the hospital said external security consultants "have found no evidence that any specific data was downloaded, tampered with, or compromised; however, the opportunity to view the data existed".
The breach was discovered on 6 September but hospital officials failed to contact FBI investigators until 20 October, according to US reports. Security consultants initially told the hospital that the breach wasn't significant and it wasn't until the full scale of the problem became apparent that the Feds were called. Notification to potential victims didn't begin until another expert compiled a list of possible marks.
The hospital said it had beefed up its security defences to guard against future attacks.
The attack is the latest of a series of attacks against US organisations that have exposed people's personal or financial information over the last two years. According to the Identity Theft Resource Centre, there were 151 such incidents across the US last year, potentially exposing the details of more than 57.7m people. ®