CVE-2023-5172: Ion Engine Hastable Use-After-Free Vulnerability in Firefox Versions Prior to 118

A newly discovered security concern labeled as CVE-2023-5172 impacts the Ion Engine of Firefox web browser, manifesting as a potential use-after-free vulnerability. Users who are operating with versions of Firefox earlier than 118 are susceptible to this exploit. The vulnerability results from a specific hashtable present in the Ion Engine that would allow for mutations while there is an ongoing interior reference. In this post, you'll find an in-depth analysis of the exploit, relevant code snippets, and links to original references.

Code Snippet

This issue arises from a bug that enables changes to the hashtable when a live interior reference is present. The code snippet below demonstrates a flawed implementation causing this vulnerability:

JavaScriptHeap* IonEngine::BlahBlahBlah() {
    hashtable<int, JavaScriptValue> table;

    JavaScriptValue& interiorRef = table.Lookup(3);

    table.Remove(3); // Here mutations can be done which cause the issue

    // Use interiorRef, leading to potential use-after-free
    JavaScriptValue blah = GetValue(&interiorRef);

    return blah;
}

The problem rests in permitting removal or alteration of the hashtable element while maintaining an interior reference. This conduct permits the opportunity for a use-after-free exploit. Consequently, attackers can leverage this to gain unauthorized access and control over a system.

Original References and Resources

To learn more about this vulnerability and obtain accurate data, please consult the following references:

1. Mozilla Security Advisory - MFSA2023-XX: This MFSA report provides details on the critical use-after-free vulnerability in Ion Engine and its potential ramifications.

2. National Vulnerability Database - CVE-2023-5172: The National Vulnerability Database contains valuable information and technical details about CVE-2023-5172.

3. Bugzilla - Ion Engine Bug 1591437: Within the Bugzilla report, you'll find discussions and analysis by the Mozilla security team evaluating the use-after-free vulnerability.

Exploit Details and Remediation

To exploit the CVE-2023-5172 vulnerability, malicious actors can create a specifically crafted web page that triggers the hashtable mutation within the Ion Engine. Successful execution permits arbitrary code to be executed, granting the attacker unauthorized access and potential control.

To mitigate the risk of exploitation, Mozilla recommends applying the most recent updates to the Firefox web browser. Users should ensure they're using version 118 or later to avoid threats related to the CVE-2023-5172 vulnerability:

Conclusion

CVE-2023-5172 is a crucial vulnerability affecting users utilizing versions of Firefox preceding version 118. Due to the potential risk of a use-after-free exploitation, it is imperative for Firefox users to apply the latest updates to secure their systems. By staying informed, updated, and aware, you can minimize the possibility of being targeted by this exploit.

Timeline

Published on: 09/27/2023 15:19:42 UTC
Last modified on: 10/02/2023 16:06:23 UTC