A warning for anyone who shopped at Target stores since Thanksgiving: Your debit and credit card information may now be in the hands of hackers.
"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.
The Secret Service earlier confirmed it was investigating the breach beginning on Black Friday weekend, and which reportedly involved nearly all Target stores nationwide.
"They are taking from cash registers essentially, called point of sale," said Don Baarns, a tech expert. "Grabbing data before it gets to computers, taking it and using it to steal money out of people's accounts."
The news put a scare into shoppers.
"My number is out there in cyberspace," said Chuck Petersen of Santa Clara, who was shopping at a Target in San Jose on Coleman Avenue. "And everything they know about me is in cyberspace, and if someone really wanted to get into my account, I'm sure they could do it."
Christina Long, a shopper at a Los Angeles Target said: "I mean, it's just scary. My mom always tells me to use credit. Don't do debit because this can happen, and I don't listen to her. I guess I should listen to her now or use cash."
Investigators believe the data stored in the cards' magnetic strips was hacked at Target cash registers, according to the security industry blog Krebs on Security, which first reported the breach and cited sources from two credit card issuers.
"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," Target said. "Among other actions, Target is partnering with a leading third-party forensics firm to conduct a thorough investigation of the incident."
The chain has 1,797 stores in the United States and 124 in Canada.
Target says anyone who suspects unauthorized activity should call them at 866-852-8680.
The office of California Attorney General Kamala Harris so far has said only that they are “aware” of the Target situation and are looking into it.
WE INVESTIGATE: Stolen Identity Dangers
Attacks on data systems aren’t confined to private companies such as Target.
Thousands of data attacks take place against State of California computer systems every year. NBC Bay Area’s Investigative Unit uncovered 24,000 residents in 2013 alone had their private, personal data compromised through supposedly secure California state computer databases.
Identity theft is the fastest growing property crime in America, according to the Federal Trade Commission, the Bay Area is at the center of it all, ranking No. 72 among metropolitan areas, with 4,521 complaints filed in 2012.