See my earlier comment here https://news.ycombinator.com/item?id=34390100
The fake packages are not part of any supply chain and are quite easy to detect. More serious attack would be rigging an existing widely used OSS package, but this is not what the post is about and its title is somewhat misleading.
When that package suddenly gets published onto the official repo, it may replace the intended package without the devs noticing until it's too late.
I think this is a flawed design for a package management tool but it's the tool we've got.
These packages could be random typosquats but they might also be targeted supply chain attacks against a specific company. With the CircleCI leak, the names of internal packages may just have leaked.
Either way, that’s not the attack described in the post, and is speculative to a degree that doesn’t warrant the “0day” descriptor. It’s also not actionable for companies that run entire PyPI mirrors rather than supplementary indexes, which is the norm.
Wow. I wonder how a repository manager like Nexus handles that. If there aren't any namespaces, would it suddenly go upstream and fetch something from the official repos?