IRS security tool goes down over security concerns

The IP PIN program was taken down, possibly over concerns similar to those that gutted the "Get Transcript" app last year.

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The IRS is once again suspending an online offering over security concerns, but this time the tool is itself a security tool.

The agency has suspended its Identity Protection Personal Identification Number (IP PIN) retrieval tool until further notice.

"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 March 7 statement.

The PINs are typically used to add a layer of security to the accounts of taxpayers who have suffered identity theft.

The concerns might have arisen over the use of knowledge-based security, which proved to be the flaw that compromised IRS' "Get Transcript" app last year. An IRS spokeswoman declined to confirm whether the IP PIN tool also relied on knowledge-based authentication -- which forces users to answer personal questions for which hackers can often Google the answers -- but the Government Accountability Office dinged the IRS for using the method for IP PIN retrieval in 2015.

Taxpayers use an IP PIN for a single filing year and receive a letter from the IRS each year with a new six-digit number, an IRS spokeswoman confirmed. In this tax-filing season so far, the IRS has mailed out roughly 2.7 million IP PINs, and 130,000 people have tried to use the online tool to retrieve IP PINs they'd lost, according to the IRS.

"You would be amazed," an IRS spokeswoman said, noting the large number of taxpayers who lose their single-use PINs.

Taxpayers will need to call the IRS to retrieve lost IP PINs. In some cases, taxpayers who have not yet received an IP PIN might be able to skip the number this year, the agency said.