https://www.bleepingcomputer.com/news/security/hackers-weaponize-microsoft-visual-studio-add-ins-to-push-malware/

Security researchers warn that hackers may start using Microsoft Visual Studio Tools for Office (VSTO) more often as method to achieve persistence and execute code on a target machine via malicious Office add-ins.

The technique is an alternative to sneaking into documents VBA macros that fetch malware from an external source.