> A dependency confusion attack or supply chain substitution attack occurs when a software installer script is tricked into pulling a malicious code file from a public repository instead of the intended file of the same name from an internal repository.
Look for `npm`, `pip`, `gem` packages, the methodology is the same : you register a public package with the same name of private one used by the company and then you wait for it to be used.
### NPM example
* List all the packages (ie: package.json, composer.json, ...)
* Find the package missing from https://www.npmjs.com/
* Register and create a **public** package with the same name
* Package example : https://github.com/0xsapra/dependency-confusion-expoit
* [Dependency Confusion: How I Hacked Into Apple, Microsoft and Dozens of Other Companies - Alex Birsan - 9 Feb 2021](https://medium.com/@alex.birsan/dependency-confusion-4a5d60fec610)
* [Ways to Mitigate Risk When Using Private Package Feeds - Microsoft - 29/03/2021](https://azure.microsoft.com/en-gb/resources/3-ways-to-mitigate-risk-using-private-package-feeds/)
