Last year, the Department of Homeland Security released a scathing report detailing Microsoft’s mistakes during a 2023 hack in which China stole thousands of emails from top government officials. Two years before that, China-linked cyberattackers compromised more than 250,000 Microsoft Exchange servers.

Researchers say Chinese actors, along with other criminal hackers, exploited a security flaw in SharePoint software widely used by governments and businesses.

Suspected Chinese hackers have broken into the email accounts of attorneys and advisers at a powerful Washington, DC, law firm in an apparent intelligence-gathering operation, the firm, Wiley Rein, told clients this week in a memo reviewed by CNN.