Financial software company Intuit said in a letter to affected customers that cyberattackers had accessed some personal and financial information of some TurboTax customers in an unprecedented series of account takeovers.

While Intuit discovered the attack with an undisclosed number of cracked TurboTax accounts during a security audit, its investigations revealed that the threat actors used login credentials such as usernames and passwords obtained from “a non-Intuit source” to gain access to the various accounts.

In order to provide clarity about the entire event, Intuit stated: “By accessing your account, the unauthorized party may have obtained information contained in a prior year’s tax return or your current tax return in progress, such as your name, Social Security number, address(es), date of birth, driver’s license number and financial information (e.g., salary and deductions), and information of other individuals contained in the tax return.”

For more information, read the original story in Bleeping Computer.