(Photo : (Photo: AP Images / Charles Krupa))
Target retail franchise store front.

Close to 40 Million customers of Target believe their credit and debit cards were hacked after making an online purchase from the popular retail store. Now Target shoppers are fearing their personal information was stolen during the holiday spending season.

"Target's first priority is preserving the trust of our guests and we have moved swiftly to address this issue, so guests can shop with confidence," said Target's Chief Executive Officer of Target Gregg Steinhafel.

The cyber-attacks occurred from November 27 through December 15, and these events affected almost every Target store in America during that period.

Krebs on Security, the highly regarded cyber-crime fighting specialist blog, revealed the identity thefts occurred due to "data stored on the magnetic stripe of cards used at the stores." Krebs on Security's founder, Brian Krebs, broke the news this week.

"On December 15, we were able to identify an unauthorized access and we were able at that time to resolve the issue," Target spokesperson Molly Snyder confirmed in a public statement.

Target has already alerted the federal government. Secret Service's representative Brian Leary confirmed the organization's involvement in the pending search.

"We regret any inconvenience this may cause," said Target's president and CEO Gregg Steinhafel in a statement. "We take this matter very seriously and are working with law enforcement to bring those responsible to justice."

This was the second major data break for a U.S. retailer with the last previously occurring when both TJ Maxx and Marshall lost the information of 45 million customers in June 2007.