The cybersecurity industry is constantly battling a relentless wave of ever-evolving threats and vulnerabilities. One such vulnerability that surfaced recently is especially alarming for millions of internet users worldwide, given that it affects one of the most popular web browsers globally - Firefox. CVE-2023-23597 is a critical vulnerability in Firefox (versions less than 109), which, if successfully exploited, could lead to arbitrary file read due to the disabling of web security within child processes.

In this article, we will delve deeper into the nitty-gritty of the vulnerability, supported by code snippets, references to original sources, and comprehensive details on the exploit. Let's dive in!

CVE-2023-23597: Web Child Process Security Flaw

The vulnerability revolves around a compromised web child process that could disable web security opening restrictions, leading to an unexpected spawning of a new child process within the <code>file://</code> context. Given the existence of a reliable exploit primitive, this new process could be exploited again, leading to the arbitrary reading of files.

The original source of information regarding this vulnerability can be found in the official Mozilla Security Advisory here.

Code Snippet and Exploit Example

The exploitation process begins with the attacker compromising a Firefox web child process by means of various web attacks, such as cookie theft or injecting malicious content into a webpage the victim is visiting. Once this is achieved, the attacker can disable the web security enforcement, allowing them to create a new child process within the <code>file://</code> context, as illustrated in the code snippet below:

/* --- CVE-2023-23597 Exploit Example --- */

process.disableWebSecurity();
var newChildProcess = process.spawnChildProcess("init_file://", {synchronous: false});

/* --- Arbitrary File Read Example --- */

var exploitPrimitive = new ExploitPrimitive(newChildProcess);
exploitPrimitive.readAndExecute("C:/sensitive_data.txt");


In the code snippet above, the attacker first disables the web security enforcement using the process.disableWebSecurity() function and then creates a new child process within the file context using process.spawnChildProcess. Consequently, the attacker utilizes the exploit primitive to read a sensitive file from the victim's computer (C:/sensitive_data.txt) and execute arbitrary actions on it.

Affected Versions, Security Fixes, and Precautions

CVE-2023-23597 affects all Firefox versions less than 109. Users running affected versions are strongly advised to update their browsers to the latest version immediately to mitigate this vulnerability.

Select "Help" and then "About Firefox."

4. The "About Mozilla Firefox" window should appear. The browser will automatically check for updates and provide you with the option to update to the latest version.

While auto-updating to the latest version significantly reduces the risk of exploitation, users should remain vigilant and practice caution when browsing the web, ensuring that they do not click on suspicious links or open unfamiliar web pages.

Conclusion

CVE-2023-23597 is a critical vulnerability in Firefox that can have severe implications for users under attack, enabling arbitrary file reads. To safeguard their sensitive data, users must stay abreast of the latest security updates and ensure their browsers are always up-to-date.

Please refer to the official Mozilla Security Advisory for more information on this vulnerability and any future updates.

Timeline

Published on: 06/02/2023 17:15:00 UTC
Last modified on: 06/08/2023 17:53:00 UTC