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high severity
- Vulnerable module: jsrsasign
- Introduced through: jsrsasign@10.9.0
Detailed paths
-
Introduced through: sacoin@Berkmann18/SaCoin#61f55573216e5efb1cd328c7857a66c4a22452f5 › jsrsasign@10.9.0Remediation: Upgrade to jsrsasign@11.0.0.
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
high severity
- Vulnerable module: web3-utils
- Introduced through: merkletreejs@0.2.32
Detailed paths
-
Introduced through: sacoin@Berkmann18/SaCoin#61f55573216e5efb1cd328c7857a66c4a22452f5 › merkletreejs@0.2.32 › web3-utils@1.10.4
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 mergeProperty 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:
Type | Origin | Short description |
---|---|---|
Denial of service (DoS) | Client | This is the most likely attack. DoS occurs when Object holds generic functions that are implicitly called for various operations (for example, toString and valueOf ). The attacker pollutes Object.prototype.someattr and alters its state to an unexpected value such as Int or Object . In this case, the code fails and is likely to cause a denial of service. For example: if an attacker pollutes Object.prototype.toString by defining it as an integer, if the codebase at any point was reliant on someobject.toString() it would fail. |
Remote Code Execution | Client | Remote code execution is generally only possible in cases where the codebase evaluates a specific attribute of an object, and then executes that evaluation. For example: eval(someobject.someattr) . In this case, if the attacker pollutes Object.prototype.someattr they are likely to be able to leverage this in order to execute code. |
Property Injection | Client | The attacker pollutes properties that the codebase relies on for their informative value, including security properties such as cookies or tokens. For example: if a codebase checks privileges for someuser.isAdmin , then when the attacker pollutes Object.prototype.isAdmin and sets it to equal true , they can then achieve admin privileges. |
Affected environments
The following environments are susceptible to a Prototype Pollution attack:
Application server
Web server
Web browser
How to prevent
Freeze the prototype— use
Object.freeze (Object.prototype)
.Require schema validation of JSON input.
Avoid using unsafe recursive merge functions.
Consider using objects without prototypes (for example,
Object.create(null)
), breaking the prototype chain and preventing pollution.As a best practice use
Map
instead ofObject
.
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
high severity
- Vulnerable module: crypto-js
- Introduced through: merkletreejs@0.2.32
Detailed paths
-
Introduced through: sacoin@Berkmann18/SaCoin#61f55573216e5efb1cd328c7857a66c4a22452f5 › merkletreejs@0.2.32 › crypto-js@3.3.0Remediation: Upgrade to merkletreejs@0.3.11.
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 nativecrypto
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.