Hackers Probably Attacked Companies Beyond Target, Report Says

Hacking attacks like those that siphoned credit-card data from Target Corp. and Neiman Marcus Group Ltd. are probably part of an unprecedented assault on a larger number of retailers, according to a security company working with the government.

The electronic break-ins may involve multiple groups of hackers who appear to be working from a sophisticated piece of software code that began circulating on underground websites last June, iSIGHT Partners, a Dallas, Texas-based security company that tracks cyber criminals, said in a report.