Cyber-Scrooges hacked the credit and debit card information of about 40 million Target customers across the country at the height of the Christmas shopping season.
The potential setback could affect people who swiped payment cards at the discount retailer's 1,797 stores starting the day before Thanksgiving to as recently as Sunday.
Customer names, payment card numbers, expiration dates and security codes were believed to have been stolen, Target officials said on the company website.
The data were obtained by software installed on point-of-sales terminals, although exactly how it happened was under investigation.
Few shoppers at the store on Santa Rosa Avenue seemed concerned about the breach, though some decided to use different payment methods than they might have otherwise.
“I wrote them a check!” said 91-year-old Robert Olsten as he left the store with about $50 worth of Christmas gifts.
Olsten said he'd heard the story on the radio Thursday morning and decided against putting his purchases on his Discover card as he would have.
Victoria Jones took the opposite approach. The 42-year-old Santa Rosa resident chose to put her cart-load of purchases on a credit card instead of her debit card, reasoning it was smarter to let the credit card company bear the risk instead of the hard-earned cash in her checking account.
“I went to swipe my debit card and went, 'Wait a minute!'” Jones said.
She said she knows she shopped at the store during the period in question, and will now keep an eye out for any unusual activity on her account.
As word of the theft spread, banking and credit union officials on the North Coast urged cardholders to monitor their accounts and report any suspicious activity. They assured customers they wouldn't be charged for any unauthorized transactions.