Dotnetfx 365.exe

A cloud-based subscription service that includes productivity apps like Word, Excel, and Teams.

The dotnetfx35setup.exe file is a self-extracting executable that installs the .NET Framework 3.5 on a Windows system. When run, it extracts the necessary files and installs the framework, which includes: dotnetfx 365.exe

If you downloaded it from a non-Microsoft source, your AV is right to be suspicious. The official file will not trigger Windows Defender. If it triggers, quarantine it and re-download. quarantine it and re-download.