The IRS has suspended an online tool used to retrieve Identity Protection PINs – a six-digit number needed by victims of tax refund fraud to file their taxes electronically – after reports that the system suffered the same security weakness that allowed fraudsters to trick another agency tool into giving up taxpayer information last year. “The IRS is conducting a further review of the application that allows taxpayers to retrieve their IP PINs online and is looking at further strengthening the security features on the tool,” the agency said in a statement Monday. Concerns about the tool were thrust into the spotlight last week after journalist Brian Krebs wrote about a South Dakota woman, Becky Wittrock, who said fraudulent tax returns were filed in her name two years in a row – and that the phony filing this year included her stolen IP PIN.