A warning for anyone who has shopped at Target stores since Thanksgiving: Your debit and credit card information may now be in the hands of hackers.
The Secret Service has confirmed thieves have stolen an unknown number of Target customers' payment information, which could affect millions who have shopped there.
"Approximately 40 million credit and debit card accounts may have been impacted between Nov. 27 and Dec. 15, 2013," Target said Thursday in a statement on its website. "Target alerted authorities and financial institutions immediately after it was made aware of the unauthorized access, and is putting all appropriate resources behind these efforts."
Several newspapers and online sites reported the credit card breach occurred the weekend of Black Friday.
"I rely on that credit card," customer Daniel Souphankhaysy said, "and if my funds aren't there, it's going to hurt my bills and everything."
Sources told media outlets the thieves stole customer credit card information from point-of-sale machines inside Target stores. They said the thefts could have occurred at nearly all of the Target stores nationwide.
"I don't know that I'll be shopping at Target in the near future," customer Elizabeth Robinson said. "I hope to hear that this is resolved."
Prof. William Kresse, a security expert at Saint Xavier University, said this could be as big as it looks.
"If it pans out the way it seems to be looking, this could be the biggest credit card breach in the history of credit card breaches."
Some security blog sites reported the thefts could have occurred until Dec. 15, and security experts say the thieves possibly used software to hack the credit card machines.
"Somehow the fraudsters were able to get a portal into the Target processing system," Kresse said, "and able to spread some Malware that went to each one of the card readers."
Those who suspect unauthorized activity should contact Target at (866) 852-8680.