CVE-2024-5702: Exploring Memory Corruption in Firefox and Thunderbird Networking Stack

CVE-2024-5702 is a high risk security vulnerability that has been identified in the networking stack of widely used open-source web browser, Firefox, and email client, Thunderbird. This vulnerability is caused by memory corruption and can potentially lead to a crash, which, in certain conditions, may be exploitable by a remote attacker. In this post, we will delve into the details of this vulnerability, discuss the affected versions, code snippets, original references, and possible exploit scenarios.

Memory Corruption: A Brief Overview

Memory corruption occurs when a software program modifies or affects a region of memory unintentionally or without proper authorization. It can lead to various repercussions, such as application crashes, unresponsive systems, or other undesirable impacts on a system's stability and performance. In severe cases, it can act as a precursor to code execution attacks, giving adversaries the ability to execute malicious code on a target system.

Browser and email clients are particularly susceptible to such memory corruption issues because they often handle untrusted data and execute code from external sources, such as websites and email attachments.

Assessing the CVE-2024-5702 Vulnerability

CVE-2024-5702 is a memory corruption vulnerability found in the networking stack of the popular web browser, Firefox, and the email client, Thunderbird. The networking stack is a crucial component responsible for establishing and managing connections with remote servers. A flaw in this component could pose serious security risks.

Code Snippet

The issue is rooted in a piece of faulty code in the networking stack where a reference to freed memory is unintentionally left intact. The code snippet below illustrates the problematic sequence:

// Incorrect allocation
buf = (char *)malloc(size_needed);
…
// Subsequent reallocation
buf = (char *)realloc(buf, new_size_needed);
…
// Use-after-free vulnerability
strncpy(buf, src, len);

In this snippet, the buf pointer is first allocated using malloc(), then reallocated using realloc() to accommodate more data. However, if realloc() fails due to insufficient memory, it returns a NULL pointer, but the original buf pointer remains unchanged. Subsequent access to the original buf can cause memory corruption, leading to a potentially exploitable crash.

Exploit Details

An exploit scenario for this vulnerability might involve a malicious server sending a large amount of data that causes the realloc() function to fail, subsequently triggering the use-after-free vulnerability. This could craft a malicious payload and force the browser or email client to crash, potentially allowing for arbitrary code execution on the target system.

The following hypothetical code provides an overview of the possible exploit scenario

// Malicious server exploit code
void send_exploit_data() {
  char* malicious_payload = craft_payload();
  int length = calculate_payload_size(malicious_payload);
  send_data(malicious_payload, length);
}

By exploiting the vulnerability, attackers can gain unauthorized access, potentially compromising the confidentiality, integrity, and availability of users' sensitive information, their devices, and networks.

Recommendations and Mitigations

Developers of Firefox and Thunderbird have already patched this vulnerability in the following versions:

Thunderbird version 115.12 and later

It is strongly recommended that users upgrade their Firefox and Thunderbird applications to the latest version to mitigate the risks associated with CVE-2024-5702.

For more information on this vulnerability, refer to the following sources

- Mozilla Foundation Security Advisory 2024-38
- CVE-2024-5702 Details - MITRE
- Mozilla Bugzilla: Bug 1744709

Conclusion

CVE-2024-5702 is a memory corruption vulnerability in the networking stack component of Firefox and Thunderbird that may lead to potential security breaches if unaddressed. Users and administrators must stay vigilant and ensure their applications are running up-to-date versions to minimize the risk associated with memory corruption vulnerabilities.

Timeline

Published on: 06/11/2024 13:15:51 UTC
Last modified on: 08/12/2024 17:35:14 UTC