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Overview

jsrsasign is a free pure JavaScript cryptographic library.

Affected versions of this package are vulnerable to Observable Discrepancy via the RSA PKCS#1.5 or RSAOAEP decryption process. An attacker can decrypt ciphertexts by exploiting the Marvin security flaw. Exploiting this vulnerability requires the attacker to have access to a large number of ciphertexts encrypted with the same key.

Workaround

The vulnerability can be mitigated by finding and replacing RSA and RSAOAEP decryption with another crypto library.

Remediation

Upgrade jsrsasign to version 11.0.0 or higher.

References

• GitHub Commit
• GitHub Issue
• Vulnerability Report

Overview

web3-utils is a Collection of utility functions used in web3.js.

Affected versions of this package are vulnerable to Prototype Pollution via the utility functions format and mergeDeep, due to insecure recursive merge. An attacker can manipulate an object's prototype, potentially leading to the alteration of the behavior of all objects inheriting from the affected prototype by passing specially crafted input to these functions.

PoC

const Web3Utils = require('web3-utils');

var BAD_JSON = JSON.parse('{"__proto__":{"polluted":true}}');
var victim = {}
console.log("Before Attack: ", JSON.stringify(victim.__proto__));
try {
  Web3Utils.format({}, BAD_JSON)
} catch (e) { }
console.log("After Attack: ", JSON.stringify(victim.__proto__));
delete Object.prototype.polluted;


console.log("Before Attack: ", JSON.stringify(victim.__proto__));
try {
  Web3Utils.mergeDeep({}, BAD_JSON)
} catch (e) { }
console.log("After Attack: ", JSON.stringify(victim.__proto__));
delete Object.prototype.polluted;

Details

Prototype Pollution is a vulnerability affecting JavaScript. 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. When that happens, this leads to either denial of service by triggering JavaScript exceptions, or it tampers with the application source code to force the code path that the attacker injects, thereby leading to remote code execution.

There are two main ways in which the pollution of prototypes occurs:

• Unsafe Object recursive merge

• Property definition by path

Unsafe Object recursive merge

The logic of a vulnerable recursive merge function follows the following high-level model:

merge (target, source)

  foreach property of source

    if property exists and is an object on both the target and the source

      merge(target[property], source[property])

    else

      target[property] = source[property]

When the source object contains a property named __proto__ defined with Object.defineProperty() , the condition that checks if the property exists and is an object on both the target and the source passes and the merge recurses with the target, being the prototype of Object and the source of Object as defined by the attacker. Properties are then copied on the Object prototype.

Clone operations are a special sub-class of unsafe recursive merges, which occur when a recursive merge is conducted on an empty object: merge({},source).

lodash and Hoek are examples of libraries susceptible to recursive merge attacks.

Property definition by path

There are a few JavaScript libraries that use an API to define property values on an object based on a given path. The function that is generally affected contains this signature: theFunction(object, path, value)

If the attacker can control the value of “path”, they can set this value to __proto__.myValue. myValue is then assigned to the prototype of the class of the object.

Types of attacks

There are a few methods by which Prototype Pollution can be manipulated:

Affected environments

The following environments are susceptible to a Prototype Pollution attack:

• Application server

• Web server

• Web browser

How to prevent

1. Freeze the prototype— use Object.freeze (Object.prototype).

2. Require schema validation of JSON input.

3. Avoid using unsafe recursive merge functions.

4. Consider using objects without prototypes (for example, Object.create(null)), breaking the prototype chain and preventing pollution.

5. As a best practice use Map instead of Object.

For more information on this vulnerability type:

Arteau, Oliver. “JavaScript prototype pollution attack in NodeJS application.” GitHub, 26 May 2018

Remediation

Upgrade web3-utils to version 4.2.1 or higher.

References

• GitHub Commit

Overview

crypto-js is a library of crypto standards.

Affected versions of this package are vulnerable to Use of Weak Hash due to inadequate security settings in the PBKDF2 configuration, which uses insecure SHA1 and has a low iteration count of 1. These insecure settings allow attackers to perform brute-force attacks when PBKDF2 is used with the default parameters.

No information is directly exposed when a hash is generated, regardless of whether the PBKDF2 function is in the vulnerable configuration or not. However, it may be possible to recover the original data, more or less easily depending on the configured parameters, using a brute force attack. This is a low impact on the confidentiality of the protected data, which are in a different scope than the vulnerable package.

The attacker similarly may be able to modify some data which is meant to be protected by the vulnerable package - most commonly when it is used for signature verification. This would require a subsequent exploitation, such as forcing a hash collision via length extension attack. The integrity of the data is therefore compromised, but the quantity and targeting of that data is not fully in the attacker's control, yielding a low integrity impact.

Notes

• This vulnerability is related to https://security.snyk.io/vuln/SNYK-JS-CRYPTOES-6032390 in crypto-es.

• According to the crypto-js maintainer: "Active development of CryptoJS has been discontinued. This library is no longer maintained." It is recommended to use the Node.js native crypto module.

Workaround

This vulnerability can be avoided by setting PBKDF2 to use SHA-256 instead of SHA-1 and increasing the number of iterations to a sufficiently high value depending on the intended use. See, for example, the OWASP PBKDF2 Cheat Sheet for recommendations.

Changelog:

2023-10-24 - Initial publication

2023-10-25 - Added fixed version, updated references, separated crypto-es, description changes, updated CVSS, added CVE ID

2023-11-07 - Re-assessed CVSS following a CVSS publication on NVD. No changes made to CVSS.

2024-01-11 - Revised CVSS and description after additional deeper investigation, to reflect the details of the severity assessment

Remediation

Upgrade crypto-js to version 4.2.0 or higher.

References

• CryptoJS Vulnerable Code
• GitHub Advisory
• GitHub Issue
• Snyk Blog Post
• X Thread