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.

Software giant Microsoft is at the center of cybersecurity storm after China-linked hackers exploited flaws in SharePoint servers to target hundreds of organizations. While such cyberattacks are not new, the scale of the onslaught and the speed with which the hackers took advantage of freshly discovered vulnerabilities is fueling concern.

The company said state-backed hacking groups were breaching systems through flaws in SharePoint, which is used by the U.S. government and companies around the world.