Chinese "threat actors" have hacked Microsoft's SharePoint document software servers and targeted the data of the businesses using it, the firm has said.

The tech giants have evidence that Chinese hackers are exploiting the new bug, but warned "multiple actors" are also hacking into affected SharePoint systems.

US tech giant Microsoft has pointed the finger at China amid a wave of cyberattacks on firms and government agencies worldwide, announcing on Tuesday that it has identified three Chinese hacker groups responsible for the damage so far.