A Quick Recap
Rather than rewrite the story, go ahead and check out the full recap and summary from npm on their blog.
What happened next is the reason we are writing this post. Azer Koçulu published a number of packages on npm, one of which was the left-pad package which is a simple bit of code that is depended upon by many other packages. After the package was unpublished, many popular projects began having build failures due to the missing package. This is concerning in itself that anyone could unpublish a dependency you have, or a dependency of a dependency of a dependency and cause you or your team real headaches. Shortly after left-pad was unpublished, the npm team decided to un-unpublish it with a new owner to fix the many breaking builds around the internet. What is more concerning though, is the fact that once a package is unpublished, anyone can grab those package names you depend on somewhere in your dependency tree and push new, potentially malicious code into your project. In general, this wouldn’t be too bad because your package likely relies on a version that was unpublished and the new published version would not be pulled in. However, many people when installing dependencies use the commands
npm i --save <package-name> or
npm i --save-dev <package-name> which by default installs the latest version published at the time preceded by a
^1.0.0 which tells npm to install any updated version through minor releases the next time dependencies are updated. This means that if you reinstall or update your project and someone has pushed malicious code into a patch (1.0.1) or minor (1.1.0) release from our example, it will automatically be installed in your project.