WASHINGTON—The Biden administration publicly blamed hackers affiliated with China’s main intelligence service for a far-reaching cyberattack on Microsoft Corp. email software this year, part of a global effort by dozens of nations to condemn Beijing’s malicious cyber activities.
The U.S. 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.
In addition, four Chinese nationals were indicted over a range of separate hacking intrusions dating back a decade that allegedly stole corporate and research secrets from firms and universities around the world. Three of the nationals were described as MSS officers, while a fourth was said to be employed at a Chinese front company that aided the hacking.
“The United States and countries around the world are holding the People’s…