In 2024, 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. In response to the 2024 report, Nadella, the CEO of Microsoft, promised to rededicate Microsoft to protecting its products and its customers from bad actors…

Shortly after Nadella took the reins, Microsoft eliminated the group that had companywide responsibility for Microsoft’s security work, pushing security decisions to the individual business units. Around the same time, Microsoft changed the way it developed software, laying off many of the test engineers charged with uncovering bugs before products ship to customers…

With regard to the July 2025 Microsoft hack, researchers said more than 400 SharePoint servers had been hacked—many of them belonging to government entities—and Microsoft had linked some of the attacks to the Chinese government…

In previous episodes, such as the massive 2021 hack of the Microsoft Exchange email system, China pulled off impressive technical feats before being caught…

Regarding the 2025 SharePoint cyberattack, Eye Security researchers discovered, on July 18, 2025 an unauthorized script on a SharePoint server belonging to one of their customers. As the Eye team dug in, they started finding the same script on about 150 other SharePoint servers all over the internet…The script opened a back door to the SharePoint servers, creating an encryption key that could be used later to run commands on the machine. “It was just like a door key left on the street,” said Kerkhofs. “It was accessible for everybody. We just started scanning and we grabbed all the keys.”…Microsoft, learning that hackers were exploiting the bugs, called in its security team.

Eventually the Eye team discovered 80 infected organizations. European government agencies were compromised, as were U.S. federal agencies, municipalities and universities…

On July 20, 2025, the Energy Department confirmed that it was a victim… News of the compromise was reported by Bloomberg, which said that the National Nuclear Security Administration was specifically victimized.

Excerpt from Robert McMillan, A Failed Microsoft Security Patch Is the Latest Win for Chinese Hackers, WSJ, July 25, 2025