Microsoft issued an emergency fix to close off a vulnerability in its SharePoint software that hackers have exploited to carry out widespread attacks on businesses and at least some federal agencies.

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

Microsoft said the company has been "coordinating closely with CISA, DOD Cyber Defense Command, and key cybersecurity partners around the world throughout our response."

A global attack on Microsoft server software used by thousands of government agencies and businesses to share documents within organisations is likely the work of a single actor, a cybersecurity researcher said on Monday.

Microsoft released an emergency security patch on Sunday to “mitigate active attacks targeting on-premises servers.”

Microsoft has alerted organizations about active attacks exploiting a vulnerability in SharePoint servers, impacting over 10,000 on-premise installations, including those at businesses and government agencies.

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Hackers exploited a security flaw in common Microsoft Corp. software to breach governments, businesses and other organizations across the globe and steal sensitive information, according to officials and cybersecurity researchers.