> I will add that most places, forums, sites don’t deliver the hash OOB. Unless you mean like GPG but that would have came from same site. For example if you download a Packer plugin from GitHub, files and hash all comes from same site.
This thread started by talking about the site serving the download (and hash) over http. Github serves their content over https, so you're not going to be MITM'ed. There are other attack vectors, but if the delivery of the content you're downloading is compromised/MITM'ed, you've lost.
If you want real integrity + provenance, you need a GPG-signed ISO and a public key obtained independently (or at least via HTTPS). Hashes alone aren’t a security measure; HTTPS + signatures are the modern minimum.