Debit cards are a convenient way to buy products online, especially for those who don't like to use credit cards. Unfortunately, the Web is one of the most dangerous places to make purchases, McNelley says.
"Online is the No. 1 place where consumers should not use their debit cards," she says. "It's susceptible at so many points. The consumer could have malware on their computer, so it could be at their endpoint that the data get compromised. It could be a man-in-the-middle attack where somebody is eavesdropping on their communications via the wireless network. And then at the other end, that data goes into a database at the merchant. As we've seen with some of the higher-profile breach events over the last year or so, that data is going to be vulnerable if (they're) not properly cared for."
Aside from the potential for hacking at many different points in a transaction, Abagnale says a fundamental problem with using debit cards online is it's impossible to know who is handling your information.
"Buying stuff online, you have to be careful because you have to know who you're doing business with. When you buy things online, what always kills me about that is people say, 'This is a safe site,'" Abagnale says. "Who works there?"