The Internal Revenue Service announced June 23 that the electronic filing PIN tool will no longer be available on IRS.gov or by toll-free phone. This is a precautionary measure to protect the system, and in response to the theft of taxpayer data, which the IRS says was stolen elsewhere.

IRS also said cybercriminals used an automated bot attack program, which accessed more than 100,000 e-File PINs through the tool. The tool does not reveal users’ data, only the PIN.

The e-File PIN serves as an alternative signature verification method on the Form 1040 series and helps assist with electronic filing of tax returns.

According to the IRS, there has been additional “questionable activity,” making the move necessary. Most taxpayers do not need an e-File PIN to file electronically, they can use their prior-year adjusted gross income from copies of their prior year tax returns. For those who do not have a copy of their tax return, they may use Get Transcript to obtain a copy which will display the adjusted gross income.

For those who do not have a copy of their tax return, they may use Get Transcript to obtain a copy which will display the adjusted gross income, according to the IRS.

IRS said they had put a number of defenses in place earlier in the year, which made it possible for them to detect the additional automated attacks “taking place at increased frequency.”

The PIN was due for removal, with the IRS saying it was “working with industry” to assess elimination of the e-File later this year.

The IRS notes that the change only affects a smaller segment of taxpayers who have not filed their tax returns this year and need a replacement e-File PIN.