The number of companies and organizations compromised by a security vulnerability in Microsoft Corp.’s SharePoint servers is increasing rapidly, with the tally of victims soaring more than six-fold in a few days,

The name was coined by Dinh Ho Anh, a researcher from Khoa of Viettel Cyber Security, who developed the exploit. The researcher said he picked the name because it exploited ToolPane.aspx, a component for assembling the side panel view in the SharePoint user interface.

Microsoft has pointed the finger at three Chinese nation-state actors. Here's what we know, plus how to guard against future attacks.

A series of cyberattacks targeting Microsoft collaboration software, specifically SharePoint, have been linked to Chinese hackers and threat actors.

Dozens of organizations appear to have been affected over the past few days by hackers targeting Microsoft server software. Microsoft said in a post on its website on Saturday that it was “aware of active attacks targeting on-premises SharePoint Server customers by exploiting vulnerabilities.