WASHINGTON—The Biden administration Monday publicly blamed hackers affiliated with China’s main intelligence service for a far-reaching cyberattack on Microsoft Corp.

email software this year, senior administration officials said, part of a global effort to condemn Beijing’s malicious cyber activities.

In addition, four Chinese nationals, including three intelligence officers, were indicted over separate hacking activity.

government has “high confidence” that hackers tied to the Ministry of State Security, or MSS, carried out the unusually indiscriminate hack of Microsoft Exchange Server software that emerged in March, senior officials said.

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