CVE-2024-5688: Garbage Collection Timing leads to Use-After-Free Exploit in Firefox and Thunderbird

A recently disclosed vulnerability, marked as CVE-2024-5688, has been found in Mozilla's Firefox and Thunderbird software. This vulnerability is specifically related to garbage collection occurring at a particular time, which could lead to a use-after-free exploit during object transplant operations. The affected products are Firefox versions prior to 127, Firefox ESR versions prior to 115.12, and Thunderbird versions prior to 115.12.

The Details

To better understand this vulnerability, it's important to first clarify some basic concepts. In JavaScript, garbage collection is a process for automatic memory management, wherein the runtime system identifies and reclaims memory that's no longer being used. This helps in preventing memory leaks, which can slow down or crash a computer system.

However, as CVE-2024-5688 reveals, this helpful process can also expose an exploitable vulnerability when it occurs during object transplant. The implantation process in question involves moving an object from one place in memory to another.

In simpler terms, the issue occurs when the garbage collection process is triggered at a specific moment during object transplantation, leading to a use-after-free exploit. This can allow an attacker to execute arbitrary code on the target system, potentially leading to severe consequences.

Code Snippet

The vulnerability can be exploited by inducing a garbage collection at a specific time during the object transplantation. This is an example of code that demonstrates the triggering of garbage collection:

function exploit() {
    // Code to induce garbage collection
    for (var i = ; i < N; i++) {
        var a = new ArrayBuffer(x200000);
    }
    // Code to manipulate object transplant
    ...
}

// Main program
exploit();

In this code snippet, a for loop creates N large memory chunks that will trigger garbage collection at the specified moment. Malicious code would then manipulate the objects subjected to transplant.

The attacker induces a garbage collection when the object is being moved (transplanted) in memory.

3. Exploiting the use-after-free vulnerability allows arbitrary code execution, which results in a successful attack.

Original References

- Mozilla Security Advisory: CVE-2024-5688
- CVE-2024-5688 Details and Fixes

Recommendations for Mitigation

It is highly recommended that users update their Firefox and Thunderbird software to the latest, patched versions that are not affected by this vulnerability. Updates can be found on the Mozilla website, using these links:

- Download Firefox
- Download Firefox ESR
- Download Thunderbird

By updating to the most recent and patched versions, users minimize the risk of their systems being exploited through the CVE-2024-5688 vulnerability. As always, it's important to stay vigilant and regularly update software to ensure the greatest possible protection against security threats.

Timeline

Published on: 06/11/2024 13:15:50 UTC
Last modified on: 07/03/2024 02:09:10 UTC