This is a major security issue. 

The official download website for reinstalling the Minecraft Java Edition Launcher (https://www.minecraft.net/en-us/download) contains a Trojan recognized by Windows as     " EUS:Win32/CustomEnterpriseBlock!cl " details on the virus are here: https://www.microsoft.com/en-us/wdsi/threats/malware-encyclopedia-description?Name=EUS:Win32/CustomCertEnterpriseBlock!cl&ThreatID=-2147236663

TO REPLICATE:

Go to the Minecraft website and download the installer for Minecraft Java Edition.

Run the installer.

Windows should recognize the Virus and create a pop-up saying that a threat was found and prompt the user to take action