But the college-prep school for kids 3 and up is offering a year of free credit monitoring to victims.
The school’s letter says it occurred in October and that those affected were identified in early November.
A disclosure to the state of Maine Wednesday says nearly 1,500 people were affected.
The disclosure was filed by Dominik Cvitanovic, an attorney for the school. He told The Atlanta Journal-Constitution the intrusion occurred Oct. 21, it was detected Oct. 22 and an ensuing investigation determined on Nov. 7 it constituted a breach.
Maine requires the disclosure of any breach affecting residents there. One of the victims lives there, according to Cvitanovic’s Wednesday disclosure to the Maine attorney general.
Carl Carlson, Walker’s head of school, said in an emailed statement to the AJC that “we are pleased with our response and our ability to minimize the impact ... .”
The statement said there was no evidence that student or parent financial or other “sensitive” information was “impacted during this incident outside of employment-related situations.”
Cvitanovic said he was not authorized to elaborate on whether that meant the victims were only current or former Walker School employees.
Public schools have been affected by hackers recently, too.
The system in Henry County turned off its computer network in mid-November after a “cyber incident” involving an unauthorized user. The shutdown has cut off internet service to students for several weeks as officials investigated. They determined that operating payroll, human resources, email and other important programs were unaffected. But Superintendent Mary Elizabeth Davis said the investigation could lead to criminal charges.