While adding support for jqfmt to my markdown code block formatter (mdsf, mdsf#700), I came across something weird.
Apparently there's a bunch of projects getting hit with this, fairly obscure ones though. Project gets forked, suddenly get a pile of stars more than the original, and then there's a curl-bash pipe inserted into it that runs some ransomeware that encrypts ~/Documents.
This isn't really a supply chain attack. It's more social engineering: fake users, forks, and non-verified code. They're taking advantage of the fact that most people don't use verified releases or packages code from open source projects.
GitHub is not compromised, nor sending unintended payloads.
But that's not a supply chain attack. If projects or platforms are compromised and THEN their code is used by normal means of ingestion of said project, that would be a supply chain attack.
These are unofficial channels created as forks of existing projects in an attempt to fool users into using these instead.