The company uncovers evidence that at least three China-based hacking groups are abusing the zero-day flaw in SharePoint software to access servers.

A newly discovered vulnerability in Microsoft’s SharePoint platform has spurred a mad frenzy from hackers — leading to breaches of some Microsoft clients.

Microsoft has accused Chinese state-sponsored groups of exploiting its SharePoint document management software to target users including large corporations and government agencies. The US software giant said on Tuesday that two groups — Linen Typhoon and Violet Typhoon — had exploited a so-called spoofing vulnerability to attack servers used by Microsoft customers.