The nation's largest arts and crafts chain, based in Irving, Texas, says that its subsidiary Aaron Brothers was also attacked.
The company said that both stores were attacked by criminals using highly sophisticated malware that had not been encountered previously by the two security firms that were conducting the investigation.
The details come nearly three months after Michaels disclosed that it may have been a victim of a data breach.
A massive security breach at Target Corp. that affected 40 million cards has many shoppers worried about the safety of their personal data.
