Version Details and Security Vulnerabilities

object-path is vulnerable to Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution'). The del() function fails to validate which Object properties it deletes. This allows attackers to modify the prototype of Object, causing the modification of default properties like toString on all objects.

Impact

A prototype pollution vulnerability has been found in object-path <= 0.11.4 affecting the set() method. The vulnerability is limited to the includeInheritedProps mode (if version >= 0.11.0 is used), which has to be explicitly enabled by creating a new instance of object-path and setting the option includeInheritedProps: true, or by using the default withInheritedProps instance. The default operating mode is not affected by the vulnerability if version >= 0.11.0 is used. Any usage of set() in versions < 0.11.0 is vulnerable.

Patches

Upgrade to version >= 0.11.5

Workarounds

Don't use the includeInheritedProps: true options or the withInheritedProps instance if using a version >= 0.11.0.

References

Read more about the prototype pollution vulnerability

For more information

If you have any questions or comments about this advisory:

• Open an issue in object-path

This affects the package object-path before 0.11.6. A type confusion vulnerability can lead to a bypass of CVE-2020-15256 when the path components used in the path parameter are arrays. In particular, the condition currentPath === '__proto__' returns false if currentPath is ['__proto__']. This is because the === operator returns always false when the type of the operands is different.

Prototype pollution vulnerability in function parseQuery in parseQuery.js in webpack loader-utils prior to version 2.0.3 via the name variable in parseQuery.js.

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 json5 v2.2.2 and later. A patch has also been backported for json5 v1 in versions v1.0.2 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 the user 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, users 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 user 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...');
}