CVE-2024-7528: Mozilla Firefox Use-After-Free Vulnerability

CVE-2024-7528 Overview

CVE-2024-7528 is a use-after-free vulnerability caused by incorrect garbage collection interaction in IndexedDB within Mozilla Firefox, Firefox ESR, and Thunderbird. This memory corruption flaw occurs when the garbage collector improperly handles IndexedDB objects, potentially allowing freed memory to be accessed and exploited by an attacker.

Critical Impact

This use-after-free vulnerability in IndexedDB can potentially allow attackers to execute arbitrary code or cause application crashes by manipulating memory through specially crafted web content.

Affected Products

• Mozilla Firefox versions prior to 129
• Mozilla Firefox ESR versions prior to 128.1
• Mozilla Thunderbird versions prior to 128.1

Discovery Timeline

• 2024-08-06 - CVE-2024-7528 published to NVD
• 2024-08-12 - Last updated in NVD database

Technical Details for CVE-2024-7528

Vulnerability Analysis

This vulnerability stems from a race condition or improper synchronization between IndexedDB operations and the JavaScript garbage collector in Mozilla's browser engine. IndexedDB is a low-level API for client-side storage of significant amounts of structured data, including files and blobs. When the garbage collector attempts to free memory associated with IndexedDB objects while those objects are still being referenced or accessed by other parts of the application, a use-after-free condition can occur.

The vulnerability requires user interaction, meaning a victim must visit a malicious webpage or open malicious content for exploitation to succeed. Once triggered, an attacker could potentially leverage the freed memory to execute arbitrary code within the context of the browser process, gaining the same privileges as the user running the affected application.

Root Cause

The root cause is classified as CWE-416 (Use After Free). The garbage collection mechanism in Mozilla's JavaScript engine fails to properly track references to IndexedDB objects during certain operations. This leads to premature deallocation of memory that is subsequently accessed, creating an exploitable condition where attacker-controlled data can be written to freed memory locations.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker would need to craft a malicious webpage containing JavaScript code that manipulates IndexedDB in a specific manner to trigger the incorrect garbage collection behavior. When a victim navigates to such a page, the vulnerability can be exploited without any additional privileges or authentication.

The exploitation sequence typically involves:

1. Creating and manipulating IndexedDB objects through JavaScript
2. Triggering specific garbage collection timing conditions
3. Accessing freed memory to achieve code execution or information disclosure

Technical details can be found in the Mozilla Bug Report #1895951.

Detection Methods for CVE-2024-7528

Indicators of Compromise

• Unusual browser crashes or instability when visiting untrusted websites
• Unexpected memory access violations in Firefox, Firefox ESR, or Thunderbird processes
• Suspicious IndexedDB activity patterns in browser developer tools
• Process crashes with memory corruption signatures in application logs

Detection Strategies

• Monitor browser process behavior for signs of memory corruption or unexpected termination
• Implement network-based detection for known exploit patterns targeting IndexedDB vulnerabilities
• Deploy endpoint detection solutions that can identify use-after-free exploitation attempts
• Review browser crash reports for patterns consistent with memory corruption attacks

Monitoring Recommendations

• Enable enhanced crash reporting in Mozilla applications to identify potential exploitation attempts
• Monitor for unusual JavaScript execution patterns on web-facing systems
• Implement browser isolation technologies to contain potential exploits
• Configure SentinelOne agents to monitor browser process behavior for anomalous memory operations

How to Mitigate CVE-2024-7528

Immediate Actions Required

• Update Mozilla Firefox to version 129 or later immediately
• Update Mozilla Firefox ESR to version 128.1 or later
• Update Mozilla Thunderbird to version 128.1 or later
• Restrict access to untrusted websites until patches are applied

Patch Information

Mozilla has released security patches addressing this vulnerability in Firefox 129, Firefox ESR 128.1, and Thunderbird 128.1. Organizations should prioritize updating all instances of affected Mozilla applications. Detailed patch information is available in the Mozilla Security Advisories:

• Mozilla Security Advisory MFSA-2024-33
• Mozilla Security Advisory MFSA-2024-35
• Mozilla Security Advisory MFSA-2024-37

Workarounds

• Consider disabling JavaScript on untrusted sites as a temporary measure using browser extensions like NoScript
• Implement browser isolation or sandboxing technologies to limit the impact of potential exploitation
• Use enterprise browser management to restrict access to potentially malicious websites
• Deploy network-based web filtering to block known malicious domains

# Verify Firefox version on Linux systems
firefox --version

# Check for automatic updates configuration
grep -r "app.update" ~/.mozilla/firefox/*.default*/prefs.js

# Force update check via command line (Linux)
firefox --check-default-browser