Description: A serious vulnerability has been discovered affecting all versions of the popular package, dom-iterator, which is widely used in the JavaScript ecosystem. The vulnerability, assigned the CVE identifier CVE-2024-21541, allows arbitrary code execution due to the use of the Function constructor without proper input sanitization.

Arbitrary code execution is a severe security vulnerability that could lead to an attacker gaining unauthorized access to a system or its data. It occurs when an attacker is able to control the input that gets passed to a function which generates new functions in JavaScript. This is particularly dangerous when the inputs are not properly sanitized or checked, which is the case in this situation.

When handling strings that contain code in JavaScript, it is essential to be extremely cautious. This is because when scripts execute attacker-controlled code, harmful side effects may be introduced, like unauthorized system access and data theft. The risks involved in this vulnerability are similar to those associated with allowing attacker-controlled input to reach eval.

Exploit Details

The vulnerability stems from the dom-iterator package's use of the Function constructor. This constructor is used for creating new functions dynamically from a string that represents the function's body.

Here is an example code snippet from the affected package

const createFunctionFromString = (str) => {
  return new Function(
    '"use strict"; return (function() { ' + str + ' });'
  )();
};

This code creates a new Function object by wrapping a given string within another function. The issue arises due to the lack of proper input sanitization before passing the user-supplied string to the Function constructor. Malicious actors can exploit this situation to execute arbitrary code within the context of the vulnerable application.

To fully understand the impact of this vulnerability, let's examine a simple use case

const maliciousCode = "console.log('I am a malicious script.');"
const generatedFunction = createFunctionFromString(maliciousCode);
generatedFunction();

In the snippet above, an attacker injects the malicious code as input to the createFunctionFromString method. This input is then used to create a new function, resulting in the arbitrary code being executed when the function is called.

Solutions and Mitigations

As of right now, no official patch has been released for this vulnerability. However, developers using the dom-iterator package can mitigate the risks by implementing proper input sanitization on the application level. Furthermore, users are encouraged to report any potential vulnerabilities they come across in the package's code, so the maintainers can take necessary action.

For more information regarding this vulnerability, please refer to the following resources

1. Official CVE Details
2. National Vulnerability Database

Conclusion

To reiterate, CVE-2024-21541 is a severe security vulnerability that affects all versions of the dom-iterator package. Developers must be cautious when handling untrusted input, and proper input sanitization should be employed to ensure these issues do not jeopardize the security of your application. Stay vigilant, and proactively collaborate with the open-source community to identify and mitigate vulnerabilities before they can be exploited.

Timeline

Published on: 11/13/2024 05:15:14 UTC
Last modified on: 11/19/2024 16:20:37 UTC