Payroll card provider Paymast'r Services recently began notifying an undisclosed number of users of its PaycheckPLUS! payroll card issued by MetaBank that their personal information was accessed by an unauthorized third party when a Web site hosted by one of its service partners was breached between July 22, 2013 and July 28, 2013.

The personal information exposed as a result of the breach may have included names, addresses, Social Security numbers, driver's license numbers and payroll card numbers.

"As soon as we learned of this issue, the site was immediately shut down and no further access is possible," the company stated in the notification letter [PDF]. "Based on a detailed investigation, we do not believe that any unauthorized activity has occurred on your Payroll Card account. Nevertheless, we take any potential privacy matter seriously and truly regret that this has happened."

It's not clear from the letter how the site was breached.

All those affected are being offered one free year of identity protection services through Kroll Advisory Solutions' ID TheftSmart program.