“A hacker attack at payroll processing firm Ceridian Corp. of Bloomington has potentially revealed the names, Social Security numbers, and, in some cases, the birth dates and bank accounts of 27,000 employees working at 1,900 companies nationwide.

In a Jan. 29 letter to an affected worker obtained by the Star Tribune, Ceridian said a hacker attacked its Internet payroll system Dec. 22 and 23.

Spokesman Keith Peterson said the breach was reported to the FBI and local authorities immediately, but affected consumers weren’t notified until this week that they were at financial risk.”

(Hacker attacks Ceridian; data from 27,000 at risk | StarTribune.com)