The Internal Revenue Service reported Tuesday that hackers had breached its "Get Transcript" application, leaking sensitive personal information on more than 100,000 users.
Last week, the IRS discovered unusual activity on the application, which allows taxpayers to download past returns. In mid-May, malicious actors were able to get past the multi-factor authentication process, which requires users to know the Social Security Number, date of birth, filing status and address of the taxpayer, as well as several personal questions.
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Once the hackers had the personal information needed to gain access to the tax records, they made some 200,000 attempts on the system, with more than half succeeding, according to IRS officials.
The "Get Transcript" application has been temporarily shut down while personnel add additional security measures.
The perpetrators did not gain access to the main tax filing servers, which remain secure, officials said.
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However, the information that was exfiltrated could be used to steal taxpayers' identities for the 2015 filing season, prompting the IRS to conduct a full review of those affected.
The hack is being investigated by the Treasury Inspector General for Tax Administration and the IRS Criminal Investigation Unit.
All taxpayers affected by the breach will be contacted by the IRS and offered free credit monitoring services.
Aaron Boyd is an awarding-winning journalist currently serving as editor of Federal Times — a Washington, D.C. institution covering federal workforce and contracting for more than 50 years — and Fifth Domain — a news and information hub focused on cybersecurity and cyberwar from a civilian, military and international perspective.
