Threat actors exploit SharePoint flaws to access internal systems, steal sensitive data, and carry out surveillance, impersonation, and extortion.

Microsoft blamed two Chinese nation-state actors for exploiting recently discovered security flaws in SharePoint to infiltrate vulnerable organizations, like schools, state governments, and the U.S. government’s top nuclear security agency.

A cyber-espionage campaign centered on vulnerable versions of Microsoft's server software now involves the deployment of ransomware, Microsoft said in a late Wednesday blog post.