CVE-2023-23602 - Mishandled Security Check in WebSockets Creating a Dangerous Path for WebWorkers
CVE-2023-23602 is a notable security vulnerability that has affected popular web browsers and email clients, including Firefox versions lower than 109, Thunderbird versions lower than 102.7, and Firefox ESR versions lower than 102.7. This startling discovery highlights the importance of understanding how this security breach takes place and the severity of its implications.
This blog post will dive into the specifics of CVE-2023-23602, starting with an analysis of the vulnerability, followed by code snippets and examples to highlight the problem, and wrapping up with links to original references and additional details on the exploit.
The Vulnerability
A significant flaw was discovered in the handling of a security check when creating a WebSocket within a WebWorker. The problem arises due to the Content Security Policy (CSP) connect-src header being ignored. This oversight can lead to connections being made to restricted origins from within WebWorkers.
To fully comprehend the implications of this vulnerability, let's first understand what WebSockets, WebWorkers, and CSP headers are.
What Are WebSockets and WebWorkers?
WebSockets are a protocol that enables a two-way, real-time communication channel between the client and the server. WebWorkers, on the other hand, are a mechanism that allows web applications to run complex, CPU-intensive tasks in the background without interfering with the application's user interface or overall performance.
Content Security Policy Connect-src Headers
The connect-src directive is part of the Content Security Policy (CSP). This directive specifies which URLs can be connected using different web APIs, such as WebSockets, WebWorkers, or XMLHttpRequests (AJAX requests).
By ignoring the CSP connect-src directive, this vulnerability allows malicious connections to restricted origins. Such connections could lead to data leakage and unauthorized access, hence posing a significant threat to users' security.
To illustrate the problem, consider the following example
<!DOCTYPE html>
<html>
<head>
<title>WebSocket Test (CVE-2023-23602)</title>
<meta http-equiv="Content-Security-Policy" content="connect-src 'self'">
<script>
// Create a WebWorker
var worker = new Worker('worker.js');
// Handle the messages from the WebWorker
worker.onmessage = function(e) {
console.log('Message received from worker:', e.data);
};
</script>
</head>
<body>
<p>WebSocket Test for CVE-2023-23602 Vulnerability</p>
</body>
</html>
In the worker.js file
// Create a WebSocket connection to a restricted origin.
var ws = new WebSocket('wss://restricted-origin.example.com');
ws.onopen = function() {
console.log('WebSocket is connected.');
};
ws.onmessage = function(e) {
console.log('Message:', e.data);
};
The code above would create a WebSocket connection to a restricted origin from inside the WebWorker (worker.js), even though the CSP explicitly states that the connect-src directive should only allow connections to the same origin (self).
Original References and Exploit Details
Several sources have explored the CVE-2023-23602 vulnerability in-depth, discussing its impact and potential consequences.
For the official details and description of CVE-2023-23602, visit: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-23602
For the Mozilla Foundation Security Advisory discussing the patched versions of the affected software, refer to: https://www.mozilla.org/en-US/security/advisories/mfsa2023-30/
It is crucial to ensure that you are running the latest versions of Firefox, Thunderbird, and Firefox ESR to prevent the exploitation of this vulnerability. The affected software can be updated to Firefox 109, Thunderbird 102.7, and Firefox ESR 102.7. By doing so, you can protect yourself from the potential adverse effects and risks associated with this issue.
In conclusion, the CVE-2023-23602 vulnerability highlights the critical nature of properly handling security checks, particularly when creating WebSockets in WebWorkers. By staying informed, understanding the vulnerability, and implementing necessary precautions, you can safeguard your digital environment from potential threats.
Timeline
Published on: 06/02/2023 17:15:00 UTC
Last modified on: 06/08/2023 16:34:00 UTC