Dairy Queen is the latest business to be targeted by credit card hackers.
The fast food restaurant says “Back-off” malware affected some 395 of its 4,500 locations between August and October.
Customer names, credit and debit cards and expiration dates were all impacted in the breach.
Although Dairy Queen says fewer than 600,000 cards in total were affected.
The company says it is offering free identity repair services for one year to any customers or franchise owners who may have had their information compromised.