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.

Microsoft Corp. warned that hackers are actively targeting customers of its document management software SharePoint, with security researchers flagging the risk of potentially widespread breaches around the world.

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.