In fact, the virus total link is literally in the description - there you can see its true nature 'Application.Hacktool.KMSActivator". It is exactly what it says it is, a "hacktool"-install works just fine and has been in use for ...
This is a false positive. OInstall.exe is a well known installer - it has been flagged by most antivirus for years now, but it is safe you can try uploading to virus total and see what other AV's flag it as (mostly AutoKMS)