From 4ac4a5c27dc5705a42ed7f607e2333d363c0a6c5 Mon Sep 17 00:00:00 2001
From: ANDRI <hostbugbounty1337@gmail.com>
Date: Mon, 2 Jan 2023 07:40:32 -0800
Subject: [PATCH] Update and Fixed Prototype Pollution in JSON5 via Parse
 Method (#35759)

Summary:
Changelog: [General][Security]

The parse method of the `JSON5` library before and including `2.2.1` does not restrict parsing of keys named `__proto__`, allowing specially crafted strings to pollute the prototype of the resulting object. This vulnerability pollutes the prototype of the object returned by JSON5.parse and not the global Object prototype, which is the commonly understood definition of Prototype Pollution. However, polluting the prototype of a single object can have significant security impact for an application if the object is later used in trusted operations.

This vulnerability could allow an attacker to set arbitrary and unexpected keys on the object returned from `JSON5.parse`. The actual impact will depend on how applications utilize the returned object and how they filter unwanted keys, but could include denial of service, cross-site scripting, elevation of privilege, and in extreme cases, remote code execution.

Suppose a developer wants to allow users and admins to perform some risky operation, but they want to restrict what non-admins can do. To accomplish this, they accept a JSON blob from the user, parse it using `JSON5.parse`, confirm that the provided data does not set some sensitive keys, and then performs the risky operation using the validated data:
```json
const JSON5 = require('json5');

const doSomethingDangerous = (props) => {
  if (props.isAdmin) {
    console.log('Doing dangerous thing as admin.');
  } else {
    console.log('Doing dangerous thing as user.');
  }
};

const secCheckKeysSet = (obj, searchKeys) => {
  let searchKeyFound = false;
  Object.keys(obj).forEach((key) => {
    if (searchKeys.indexOf(key) > -1) {
      searchKeyFound = true;
    }
  });
  return searchKeyFound;
};

const props = JSON5.parse('{"foo": "bar"}');
if (!secCheckKeysSet(props, ['isAdmin', 'isMod'])) {
  doSomethingDangerous(props); // "Doing dangerous thing as user."
} else {
  throw new Error('Forbidden...');
}
```
If an attacker attempts to set the `isAdmin` key, their request will be rejected:
```js
const props = JSON5.parse('{"foo": "bar", "isAdmin": true}');
if (!secCheckKeysSet(props, ['isAdmin', 'isMod'])) {
  doSomethingDangerous(props);
} else {
  throw new Error('Forbidden...'); // Error: Forbidden...
}
```
However, attackers can instead set the __proto__ key to {"isAdmin": true}. JSON5 will parse this key and will set the isAdmin key on the prototype of the returned object, allowing the attacker to bypass the security check and run their request as an admin:
```js
const props = JSON5.parse('{"foo": "bar", "__proto__": {"isAdmin": true}}');
if (!secCheckKeysSet(props, ['isAdmin', 'isMod'])) {
  doSomethingDangerous(props); // "Doing dangerous thing as admin."
} else {
  throw new Error('Forbidden...');
}
```
CVE-2022-46175
[CWE-1321](https://cwe.mitre.org/data/definitions/1321.html)

Pull Request resolved: https://github.com/facebook/react-native/pull/35759

Reviewed By: christophpurrer

Differential Revision: D42304806

Pulled By: rshest

fbshipit-source-id: 4ad338c878e8a235ea6b22d9f4d203c8f7779a63
---
 yarn.lock | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/yarn.lock b/yarn.lock
index 8a59eb5297fc5e..1167ca5d7f7de2 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5708,9 +5708,9 @@ json-stringify-safe@~5.0.1:
   integrity sha1-Epai1Y/UXxmg9s4B1lcB4sc1tus=
 
 json5@^2.1.0, json5@^2.2.1:
-  version "2.2.1"
-  resolved "https://registry.yarnpkg.com/json5/-/json5-2.2.1.tgz#655d50ed1e6f95ad1a3caababd2b0efda10b395c"
-  integrity sha512-1hqLFMSrGHRHxav9q9gNjJ5EXznIxGVO09xQRrwplcS8qs28pZ8s8hupZAmqDwZUmVZ2Qb2jnyPOWcDH8m8dlA==
+  version "2.2.3"
+  resolved "https://registry.yarnpkg.com/json5/-/json5-2.2.3.tgz#78cd6f1a19bdc12b73db5ad0c61efd66c1e29283"
+  integrity sha512-XmOWe7eyHYH14cLdVPoyg+GOH3rYX++KpzrylJwSW98t3Nk+U8XOl8FWKOgwtzdb8lXGf6zYwDUzeHMWfxasyg==
 
 jsonfile@^4.0.0:
   version "4.0.0"