Security researchers say Microsoft customers should take immediate action to defend against the ongoing cyberattacks, and must assume they have already been compromised.

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

New York: Microsoft has released an urgent security fix to address a critical vulnerability in its widely-used SharePoint software that hackers have exploited in attacks targeting businesses and some US government agencies.