Equifax: credit firm was breached before massive May hack

Maligned Atlanta-based agency finally goes public on earlier data breach, which happened in March, following reports company only notified payroll customers

Equifax, the credit monitoring agency that lost personal data of 143 million US customers in a massive hack in May, has revealed that it was also the victim of an earlier breach in March.

The earlier breach was serious enough for the company to notify customers, and bring in the information security firm Mandiant to investigate. But the millions of Americans whose personal data the company stockpiles to power its services are not technically customers of the company, and so it did not inform them.