CVE-2023-29532: Exploiting Mozilla Maintenance Service for Unsigned Update File Installation on Windows

A recent vulnerability has been discovered, dubbed CVE-2023-29532, which affects the Mozilla Maintenance Service on Windows operating systems. This particular vulnerability allows local attackers to trick the Mozilla Maintenance Service into applying an unsigned update file, thus potentially allowing them to execute malicious code on the affected system. This article will provide a rundown of the vulnerability, the exploit details, and how to protect your system from this attack.

Vulnerability Details (CVE-2023-29532)

Mozilla applications such as Firefox and Firefox ESR are affected by this vulnerability, as well as Thunderbird. Specifically, the issue affects versions of Firefox below 112, Firefox ESR below 102.10, and Thunderbird below 102.10, running on Windows operating systems. Other operating systems are not affected by this vulnerability.

The CVE-2023-29532 vulnerability stems from an issue with the Mozilla Maintenance Service's update process. The Service is supposed to perform a signature check on update files before applying them. If the file is hosted on a malicious SMB server, an attacker can replace the update file after the signature check has taken place, which allows them to bypass the signature check process and execute an unsigned update file.

The vulnerability exists due to the Mozilla Maintenance Service's write-lock not working on SMB servers. As a result, an attacker can take advantage and point the service to an unsigned update file on a malicious SMB server.

Exploit Details

To exploit this vulnerability, an attacker would need local system access. This means that the attacker must have access to the target computer physically or through malware that is already installed on the target system.

Once the attacker has gained local system access, they can exploit the CVE-2023-29532 vulnerability by pointing the Mozilla Maintenance Service to an unsigned update file hosted on a malicious SMB server.

Here is a simplified code snippet of what the exploitation process could look like

# Exploit for CVE-2023-29532

def replace_update_file_after_signature_check(target_server, malicious_update_file):
	# Wait for the signature check to complete on the target server
	wait_for_signature_check_completion(target_server)

	# Replace the target server's update file with the malicious update file
	replace_file(target_server.update_file, malicious_update_file)

def main():
	target_server = get_target_server() # Get the target server running the Mozilla Maintenance Service
	malicious_update_file = get_malicious_update_file() # Get the malicious update file

	replace_update_file_after_signature_check(target_server, malicious_update_file)

if __name__ == "__main__":
	main()

How to Protect Your System

To protect your system from this attack, you should ensure that your Mozilla applications are up-to-date. The latest versions of Firefox, Firefox ESR, and Thunderbird have fixed this vulnerability.

Additionally, it's a best practice to restrict access to your local systems and SMB server shares to only authorized individuals. By doing so, it decreases the potential risk of local attackers exploiting this vulnerability.

For more information about this vulnerability, you can refer to the following original sources

1. Mozilla Foundation Security Advisory
2. CVE-2023-29532 - NVD Details
3. Mitre CVE-2023-29532

In conclusion, CVE-2023-29532 is a significant security vulnerability affecting the Mozilla Maintenance Service on Windows systems. By understanding the vulnerability, its exploit details, and how to protect your system, you can safeguard your valuable data from potential harm.

Timeline

Published on: 06/19/2023 10:15:00 UTC
Last modified on: 06/27/2023 08:27:00 UTC