🚨 [security] Update json5: 2.1.3 → 2.2.2 (minor) #155

depfu · 2022-12-29T02:11:31Z

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🚨 Your current dependencies have known security vulnerabilities 🚨

This dependency update fixes known security vulnerabilities. Please see the details below and assess their impact carefully. We recommend to merge and deploy this as soon as possible!

Here is everything you need to know about this update. Please take a good look at what changed and the test results before merging this pull request.

What changed?

✳️ json5 (2.1.3 → 2.2.2) · Repo · Changelog

Security Advisories 🚨

🚨 Prototype Pollution in JSON5 via Parse Method

The parse method of the JSON5 library before and including version 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.

Impact

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.

Mitigation

This vulnerability is patched in json v2.2.2 and later.

Details

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:
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:
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:
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...');
}

Release Notes

2.2.2

Fix: Properties with the name __proto__ are added to objects and arrays.
(#199) This also fixes a prototype pollution vulnerability reported by
Jonathan Gregson! (#295).

2.2.1

Fix: Removed dependence on minimist to patch CVE-2021-44906. ([#266])

2.2.0

New: Accurate and documented TypeScript declarations are now included. There is no need to install @types/json5. ([#236], [#244])

Does any of this look wrong? Please let us know.

Commits

See the full diff on Github. The new version differs by 36 commits:

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