NEW YORK (CBSNewYork/AP) -- The fallout from what's being called the second-largest credit card breach in U.S. history prompted a big change in business by the nation's biggest bank.
More than a third of Chase bank branches opened their doors on Sunday to assist customers affected by Target's security breach.
The bank contacted about two million affected debit card members Saturday and said they would be limited to a maximum of $100 cash withdrawals and $300 in purchases per day.
Less than 10 percent of Chase customers are affected, said spokeswoman Kristin Lemkau. The limits will be in place until Chase replaces the cards. Chase credit cards are not restricted.
Meanwhile, the attorneys general of at least four states -- Connecticut, Massachusetts, New York and South Dakota -- have asked Target for information about the lapse, USA Today reported.
Over the weekend, Target offered 10 percent discounts to all customers and free credit monitoring services to customers whose bank cards may have been compromised.
Target says it's heard of "very few'' reports of fraud since thieves stole the credit and debit card information of about 40 million shoppers. But the chain is continuing to reach out to customers.
On Sunday, Sen. Charles Schumer said it is time for the Consumer Financial Protection Bureau to open an investigation into the breach.
"Not only do the American people have the right to know how this happened, but by revealing the information, it allow other stores to learn from this experience," Schumer said.
The U.S. has become the juiciest target for hackers hunting credit card information and experts say incidents like the recent data theft at Target's stores will get worse before they get better.
That's in part because U.S. credit and debit cards rely on an easy-to-copy magnetic strip on the back of the card, which stores account information.
In most other countries, people carry cards that use digital chips to hold account information.
The breach that exposed the credit card and debit card information of as many as 40 million Target customers is still under investigation. It's unclear how it occurred and what data, exactly, criminals have.
Although experts say no security system is fail-safe, there are measures companies can take to protect against these attacks.
Thankfully, individual customers are not on the hook for fraudulent charges that result from security breaches. But such attacks do raise costs -- and, likely, fees for all customers.
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