Massachusetts agency says virus led to data breach

A virus that infected as many as 1,500 computers in Massachusetts unemployment offices may have allowed criminals to steal Social Security numbers and other data of individuals and businesses, a state agency warned today.

The W32.QAKBOT data-stealing virus infected the computers on the network of the Department of Unemployment Assistance and Career Services, as well as computers at One Stop Career Centers, according to a statement from the Massachusetts Labor and Workforce Development agency.

It's unclear how many individuals and employers might be affected. The virus only affects people who had their files manually accessed and employers who manually filed their quarterly statements at an infected computer between April 19 and May 13, the agency said.

"There is a possibility that as a result of the infection, the virus collected confidential claimant or employer information. This information may include names, Social Security Numbers, Employer Identification Numbers, email addresses and residential or business addresses," the statement said. "It is possible that bank information of employers was also transmitted through the virus. Only the 1,200 employers that manually file could be impacted by the possible data breach."

The agency is notifying people who may have been affected and is working with the Massachusetts attorney general's office to investigate the breach.