Debit cards appeal to two groups: consumers and, increasingly, thieves.

Katy Henthorne became the victim of thieves who stole her PIN, or personal identification number, and then her money.

"Honestly, I was livid," Henthorne said. "I was furious, and I was angry and a little scared that somebody had managed to get into my account so easily."

Thieves were able to copy Henthorne's debit-card information, including her PIN and account number. She said she is grateful her bank spotted the theft almost immediately.

"They saved me potentially thousands of dollars," Henthorne said.

But the equipment thieves need to copy your debit-card information is easily available – sold online.

"Criminals secretly install a device called a skimmer on your ATM machine," Tobie Stanger, of Consumer Reports, said.

Thieves then use the stolen information to create a new card.

"Your whole account could be wiped out, including money you had set aside for your mortgage, for your car payment, for other payments," said attorney John Campbell, who helps victims of bank-card theft.

Consumers are most vulnerable at places such as gas stations, convenience stores and airports, where it's easier to install skimmers. However, even at a bank ATM, check to make sure nothing is loose or out of place.

You can take some simple actions to protect your account.

"When you're making a purchase with your bank card, press 'credit,' not 'debit,'" Stanger said.

Money is still deducted immediately as if you used a debit card, but buyers don't punch in their PIN code, so a criminal can't steal it. In most cases when the credit option is used, consumers are responsible for only $50 of any loss.

Henthorne said she learned not to use her PIN unless the bank teller asks for it.

Another way to protect yourself against debit-card theft: Check your account online frequently. That lets you quickly spot any suspicious activity.

Federal law limits your liability for fraudulent debit-card charges, but with some banks, you can lose up to $500 if you don't report any problem you find – or the loss of your card – within two business days.

Debit cards backed by Visa and MasterCard have zero liability, but straightening out your account can involve some headaches, since money spent by crooks is taken out of your account immediately.