By Barry Eitel

SAN FRANCISCO 

A Senate committee sent a letter Wednesday to the federal tax agency demanding answers regarding a cybersecurity breach involving the tax information of more than 100,000 Americans.

The Internal Revenue Service (IRS) said Tuesday that hackers were able to impersonate individuals using stolen information and gain access to old tax returns for 104,000 taxpayers. The breach occurred during this year’s tax season between February and the middle of this month, when the agency discovered the hacking and stopped it.

At a press conference Tuesday, IRS Commissioner John Koskinen told reporters that hackers attempted to access the tax information of approximately 200,000 Americans and succeeded in roughly half of their attempts. He also noted that the agency suspects the hackers were fairly sophisticated and well-funded.

“We’re confident that these are not amateurs, that these are actually organized crime syndicates,” Koskinen said.

In the letter sent to Koskinen Wednesday, Senate Finance Committee Chairman Orrin Hatch, a Utah Republican, requested detailed information about the nature of the breach as well as how the IRS plans to improve its digital security strategy.

“Every year, the IRS collects more than 140 million individual tax returns, roughly 6 million corporate tax returns, and millions of sensitive information returns and other filings,” Hatch wrote. “It is no exaggeration to say that the confidential taxpayer information your agency holds is of the utmost private nature for every single taxpayer in the United States.”

Hatch noted that he and Oregon Sen. Ron Wyden, the head Democrat on the Finance Committee, will conduct an investigation into how hackers could target electronic tax preparation.

Koskinen explained Tuesday that investigators believed the hackers were attempting to obtain this year’s tax information in order to file fake returns in the future. He said hackers had already obtained certain information, like social security numbers, from other sources.

“This is not a security breach. Our basic information is secure,” he said. “These are criminals who had enough data to try and impersonate the taxpayer,” he added.