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.

The hackers behind the initial wave of attacks exploiting a zero-day in Microsoft SharePoint servers have so far primarily targeted government organizations, according to researchers as well as news reports.

Among the attackers now actively exploiting vulnerable on-premises Microsoft SharePoint servers, at least one has shown indications of originating from China, according to the assessment of researchers at Google Cloud-owned Mandiant.

A major cyberattack has hit Microsoft's SharePoint platforms, putting thousands of organizations at risk around the world. The attack began