Security Fix for Prototype Pollution - huntr.dev

[huntr-helper]

https://huntr.dev/users/alromh87 has fixed the Prototype Pollution vulnerability 🔨. alromh87 has been awarded $25 for fixing the vulnerability through the huntr bug bounty program 💵. Think you could fix a vulnerability like this?

Get involved at https://huntr.dev/

Q | A
Version Affected | ALL
Bug Fix | YES
Original Pull Request | 418sec#2
Vulnerability README | https://github.com/418sec/huntr/blob/master/bounties/npm/json8-patch/1/README.md

User Comments:

📊 Metadata *

json8-patch is vulnerable to Prototype Pollution.
This package allowing for modification of prototype behavior, which may result in Information Disclosure/DoS/RCE.

Bounty URL: https://www.huntr.dev/bounties/1-npm-json8-patch

⚙️ Description *

Prototype Pollution refers to the ability to inject properties into existing JavaScript language construct prototypes, such as objects.
JavaScript allows all Object attributes to be altered, including their magical attributes such as proto, constructor and prototype.
An attacker manipulates these attributes to overwrite, or pollute, a JavaScript application object prototype of the base object by injecting other values.
Properties on the Object.prototype are then inherited by all the JavaScript objects through the prototype chain.

💻 Technical Description *

Fixed by avoiding setting magical attributes.

🐛 Proof of Concept (PoC) *

1. Create the following PoC file:

// poc.js
var json8Patch = require("json8-patch")
var obj = {}
const patch = [{op: "add", path: "/__proto__/polluted", value: "Yes! Its Polluted"}];
console.log("Before : " + obj.polluted);
json8Patch.apply(obj, patch);
console.log("After : " + {}.polluted);

2. Execute the following commands in another terminal:

npm i json8-patch # Install affected module
node poc.js #  Run the PoC

3. Check the Output:

Before : undefined
After : Yes! Its Polluted

🔥 Proof of Fix (PoF) *

After fix execution will block prototype pollution and throw an exception according to herror handling in lib, see https://github.com/sonnyp/JSON8/blob/master/packages/patch/lib/walk.js#L23-L25

👍 User Acceptance Testing (UAT)

After fix functionality is unafected

[JamieSlome]

@sonnyp - same as the other, let me know if you have any questions! 🍰

[sonnyp]

I'm confused.

Are you @luci-m-666 ?

If so why did you submit (twice) the same code changes as #117 ? Why are those commits made by @alromh87 ?

If not why claiming credit?

[sonnyp]

duplicate of duplicate of #117

[alromh87]

Maybe because @luci-m-666 loved much my work 😋

He also pushed this changes two days after me:

flitbit/json-ptr#26

Maybe he didn't copied just got exactly the same thinking as I do, character by character 🙃