Red flags would be raised, for instance, for payment card data submitted from any IP address in Eastern Europe, or card numbers that have traversed through so-called anonymizer sites that hide the originating IP address. But there's plenty of US domestic online fraud attempts to worry about, too, Fiorentino adds.

TigerDirect handles 20,000 to 40,000 orders for its goods each day, depending on the time of year, and most are shipped the same day the order is received. But online fraud attempts slow things down and place a burden on productivity.

"In our automated system, 83% of our orders require no manual review," says Fiorentino. But the remaining 17 percent of orders get a red flag that requires human intervention. Possible actions might include calling a customer, a bank or other steps to ensure credit-card fraud won't occur.

In spite of caution and preemptive actions, TigerDirect will still get hit by costly card-related fraud each year through a small percentage of bad sales -- which the retailer absorbs, not the victim of the stolen card. "It costs us millions and it costs the industry billions," Fiorentino says.

One step the company has recently taken is to use a service from fraud-management service provider Ethoca that provides a secure way for businesses accepting payment cards to share information about fraudulent card use instantly with each other. This is done in an anonymous way, so merchants can check to see if specific card fraud is occurring with another merchant.

The idea is that retailers collaborating together to discretely share fraud data will result in a better defense than each one of them on their own, Fiorentino says.