BEIJING — Microsoft said that Chinese state-sponsored groups were exploiting vulnerabilities in one of its popular collaboration software products, SharePoint, which is used by U.S. government agencies and many companies worldwide.
Microsoft said in a notice on its security blog Tuesday that it had identified at least two China-based groups linked to the Chinese government that it said had been taking advantage of security flaws in its SharePoint software. Such attacks aim to sneak into the computer systems of users.
Those groups, called Linen Typhoon and Violet Typhoon, were ones that Microsoft said it had been tracking for years and which it said had been targeting organizations and personnel related to government, defense, human rights, higher education, media, and financial and health services in the United States, Europe and East Asia.
Microsoft said another entity, which it called Storm-2603, was also involved in the hacking campaign. It said it had “medium confidence” that Storm-2603 was a “China-based threat actor.”
The U.S. government’s Cybersecurity and Infrastructure Security Agency issued a notice that said it was aware of the hacking attack on SharePoint. It added that it had notified “critical infrastructure organizations” that were affected.
“While the scope and impact continue to be assessed,” the agency said, the vulnerabilities enable “malicious actors to fully access SharePoint content, including file systems and internal configurations and execute code over the network.”
A Microsoft spokesperson wrote in an emailed response that the company had been “coordinating closely” with the Cybersecurity and Infrastructure Security Agency, the Department of Defense’s Cyber Defense Command and “key cybersecurity partners globally throughout our response.”
The Chinese Embassy in Washington did not immediately respond to a request for comment. China has routinely denied being behind cyberattacks and asserts that it is a victim of them.
Microsoft said in its blog post that investigations into others also using these exploits were still ongoing.
Eye Security, a cybersecurity firm, said that it had scanned more than 23,000 SharePoint servers worldwide and discovered more than 400 systems had been actively compromised.
The cybersecurity firm also noted that the breaches could allow hackers to steal cryptographic keys that would allow them to impersonate users or services even after the server was patched. It said users would need to take further steps to protect their information.
James Corera, director of the cyber, technology and security program at the Australian Strategic Policy Institute, a research group, said that being able to deploy back doors to enable long-term access was “a level of sophistication typically associated with the most advanced actors.”
While there was no public confirmation that the Chinese hackers had stolen those cryptographic keys, it was clear that China’s state-sponsored operations had become increasingly precise in recent years, he said.
“Chinese state-sponsored cyber actors have steadily evolved from opportunistic to highly disciplined operators,” Corera wrote in written responses to questions. “What we’re seeing now is a level of sophistication in initial access, lateral movement and credential harvesting that exceeds what many governments and vendors had anticipated.”
Indeed, U.S. officials have grown increasingly alarmed by Chinese hacking capabilities. During a breach of the U.S. telecommunications system last year, a group linked to a Chinese intelligence agency was able to listen in on telephone conversations and read text messages, members of Congress said. The hack was considered so severe that in November, President Joe Biden took it up directly with Xi Jinping, China’s leader, when they met in Peru.
With this latest breach, a researcher with Viettel Cyber Security, a Vietnamese security firm, uncovered the SharePoint vulnerability at a May security conference called Pwn2Own in Berlin. On May 16, the researcher won a $100,000 award at the conference for uncovering the weakness.
The vulnerability was shared with Microsoft on May 29, according to the Zero Day Initiative, which tracks security exposures and hosted the security conference.
Microsoft said it noticed hackers had been trying to use the software weaknesses to gain access to “target organizations” since July 7. The company issued security updates the next day, as part of its monthly batch of security patches, and urged users to install them immediately.
But those patches only partially solved the problem. Microsoft said on July 19 that it was aware of attempts to exploit those vulnerabilities, and has since issued updates to its patches and guidance to customers that it says, if followed, “fully protect customers.”
Cybersecurity firms had said that they believed Chinese actors were among those attackers, even before Microsoft said so Tuesday.
SharePoint helps organizations create websites and manage documents. It integrates with other Microsoft services such as Office, Teams and Outlook.
Microsoft said the vulnerabilities affected only on-premises SharePoint servers, meaning those managed by organizations on their own computer networks and not those operated on Microsoft’s cloud.
Palo Alto Networks, a cybersecurity company, said in a post about the breach that on-premises servers “particularly within government, schools, health care (including hospitals) and large enterprise companies” were “at immediate risk.”
“A compromise in this situation doesn’t stay contained, it opens the door to the entire network,” the cybersecurity company said.
This article originally appeared in The New York Times.