MasterCard's Online Fraud Monitor service will use a proprietary risk-scoring model that will look at factors such as account spending, transaction histories and device-level activity to calculate the likelihood of fraud on an individual ATM transaction, Sargent said. For instance, if a card that in the past has been used only domestically were to be used in a large transaction in a foreign country, the transaction would automatically be flagged as high-risk for follow-up action.

MasterCard has been offering a similar fraud-detection capability for credit card and signature-based ATM transactions for some time now. With the new service, the company is extending the same capability to PIN-based transactions.

A lot of effort has gone into ensuring that the new service will not lengthen debit card transaction times or result in too many false positives, Sargent said. A "significant amount" of historical transaction data and data on fraudulent transactions has gone into the development of the risk model, he said.

"We want to minimize to the extent possible false positives while hitting the sweet spot in finding fraudulent transactions," he said. "The model that we have built looks for anomalous behavior with a great level of accuracy."

MasterCard already offers a similar fraud-detection capability for credit card and signature-based ATM transactions via its Expert Monitoring System and MasterCard Alerts services. With the new service, MasterCard is extending the same capability to PIN-based transactions.