Stealing credentials with a malicious node module

A common misconception I’ve seen while talking to people in the node ecosystem is that a module’s “reach” is contained to the context it is used in. This is not the case. Every single module you import, if turned malicious, can affect any other module that you depend on. To demonstrate this concept, I’ve created the module multiply-by-two. This module contains a syncronous function which returns the provided number multiplied by two. Additionally, if you use express and Stripe, it will capture your users’ credit card details via an injected XSS attack.