Microsoft says state-backed Russian hackers accessed emails of senior leadership team members

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Microsoft says state-backed Russian hackers broke into its corporate email system and accessed accounts of members of the company’s leadership team, as well as those of cybersecurity and legal employees

BOSTON — State-backed Russian hackers broke into Microsoft's corporate email system and accessed the accounts of members of the company's leadership team, as well as those of employees on its cybersecurity and legal teams, the company said Friday.

In a blog post, Microsoft said the intrusion began in late November and was discovered on Jan. 12. It said the same highly skilled Russian hacking team behind the SolarWinds breach was responsible.

“A very small percentage” of Microsoft corporate accounts were accessed, the company said, and some emails and attached documents were stolen.

A company spokesperson said Microsoft had no immediate comment on which or how many members of its senior leadership had their email accounts breached. In a regulatory filing Friday, Microsoft said it was able to remove the hackers' access from the compromised accounts on or about Jan. 13.

“We are in the process of notifying employees whose email was accessed,” Microsoft said, adding that its investigation indicates the hackers were initially targeting email accounts for information related to their activities.

The Microsoft disclosure comes a month after a new U.S. Securities and Exchange Commission rule took effect that compels publicly traded companies to disclose breaches that could negatively impact their business. It gives them four days to do so unless they obtain a national-security waiver.

In Friday's SEC regulatory filing, Microsoft said that “as of the date of this filing, the incident has not had a material impact” on its