By Katie Bo Williams - 02/10/16 09:25 AM EST
Identity thieves used an automated bot in an attempt to generate phony login information to breach the Internal Revenue Service (IRS), the agency said Tuesday.
Using Social Security numbers stolen from elsewhere, the thieves used malware to try to create e-file PINs, used by some taxpayers to file their returns.
An internal investigation identified unauthorized attempts involving around 464,000 Social Security numbers, 101,000 of which were used to successfully access an e-file PIN in December.
The announcement comes as IRS Commissioner John Koskinen is set to testify Wednesday morning before the Senate Finance Committee in a hearing on the president’s budget, which boosts the agency’s funding by 4.7 percent.
In August, the agency revealed that hackers had been able to swipe sensitive information about more than 300,000 taxpayers, causing outrage among lawmakers.
Senate Finance Committee Chairman Orrin HatchOrrin HatchGOP lawmakers ask IRS to explain M wasted on unusable email system GOP senators avoid Trump questions on rigged election Schumer says Pacific trade pact may have enough votes to pass the Senate MORE (R-Utah) was critical of the agency at the time of the breach, calling it “simply unacceptable.”
“This agency has been repeatedly warned by top government watchdogs that its data security systems are inadequate against the growing threat of international hackers and data thieves,” he said in May, when the breach was first uncovered.
The IRS has often pointed to budget constraints as a chief reason it struggles to keep up with identity thieves.
Earlier this month, a number of the IRS’s tax processing systems went down because of what the agency described as technical problems, sparking lawmaker suspicions.
Although the agency continues to insist the outage was a glitch, House Oversight Committee Chairman Jason ChaffetzJason ChaffetzHouse panel tells fed agency to stop selling recalled cars Trump's big worry isn't rigged elections, it's GOP establishment State pushes back on GOP calls for 'quid pro quo' investigation MORE (R-Utah) has used the incident to renew his calls for Koskinen to be fired.
“I have zero confidence, zero, in IRS Commissioner John Koskinen,” he said.
The agency said Tuesday that this latest incident “is not connected or related to last week’s outage of IRS tax processing systems.”