Microsoft has observed three China-based threat actors, Linen Typhoon, Violet Typhoon and Storm-2603, exploiting the SharePoint vulnerabilities

More details emerged on the ToolShell zero-day attacks targeting SharePoint servers, but confusion remains over the vulnerabilities.

Microsoft is following up and is also releasing a patch for the 2016 edition of Sharepoint. Admins should install this immediately.

A new vulnerability dubbed ToolShell is being used to compromise on-premise instances of Microsoft SharePoint servers. Attacks have ranged from highly targeted to opportunistic based on the value of the company operating the server.

At least 85 servers worldwide have been compromised through a Microsoft service vulnerability that has been used to achieve remote code execution.