For anyone who thought headlines about data breaches were so 2011, the March 30 hacker attack that has affected up to 1.5 million Visa and MasterCard cardholder accounts is a reminder that companies are hardly in the clear. Yet with this latest breach—which compromised the systems of a third-party payments processor called Global Payments Inc.—comes the question: When will companies start to see this coming?

A persistent problem, says Matthew Lane, chief technology officer for information security and privacy consultancy Janus Associates, is that many firms still think they won’t become targets.