A cyberattack on the IRS may have been 7 times larger than the agency initially reported

A cyberattack targeting the Internal Revenue Service (IRS) may have allowed hackers to access 724,000 taxpayer accounts.

When the IRS first reported the attack in May last year, the agency claimed that criminals had used credentials obtained from “non-IRS sources” to successfully access about 100,000 “Get Transcript” accounts.

The online “Get Transcript” service was shut down “temporarily” and has been available only by mail since then.

In August, the IRS said that further review of the attack revealed an additional 220,000 accounts may have been accessed, and that an additional 170,000 were unsuccessfully attacked.

Friday’s statement that a further 390,000 accounts had been potentially accessed — with an additional 295,000 unsuccessfully attacked — marks the second time that the figure has been more than doubled.

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