CVE-2024-5701: Mozilla Firefox RCE Vulnerability

CVE-2024-5701 Overview

CVE-2024-5701 is a collection of memory safety vulnerabilities discovered in Mozilla Firefox version 126. These bugs exhibited evidence of memory corruption, and Mozilla presumes that with sufficient effort, some of these vulnerabilities could have been exploited to achieve arbitrary code execution. The vulnerability is classified as an Out-of-Bounds Write (CWE-787) and affects all Firefox versions prior to 127.

Critical Impact

Memory safety bugs with evidence of memory corruption that could potentially be exploited for arbitrary code execution, affecting all Firefox users on versions below 127.

Affected Products

• Mozilla Firefox versions prior to 127
• All platforms running vulnerable Firefox versions (Windows, macOS, Linux)

Discovery Timeline

• 2024-06-11 - CVE-2024-5701 published to NVD
• 2025-04-03 - Last updated in NVD database

Technical Details for CVE-2024-5701

Vulnerability Analysis

This vulnerability encompasses multiple memory safety bugs identified in Firefox 126. The Out-of-Bounds Write classification (CWE-787) indicates that the browser's code was writing data beyond the boundaries of allocated memory buffers. Memory corruption vulnerabilities of this nature are particularly dangerous in browser contexts, as browsers process untrusted content from the web continuously.

The vulnerability requires no privileges or user interaction to exploit via network-based attacks. An attacker could potentially craft malicious web content that triggers these memory safety issues when processed by a vulnerable Firefox browser, potentially leading to arbitrary code execution within the browser's context.

Root Cause

The root cause stems from inadequate memory boundary checking within Firefox 126's codebase. Multiple components exhibited improper memory handling that allowed writes beyond allocated buffer boundaries. These issues were identified through Mozilla's internal security processes and tracked across multiple bug reports.

Attack Vector

The attack vector is network-based, requiring an attacker to deliver malicious content to a victim's browser. This could be accomplished through:

• Hosting malicious content on a compromised or attacker-controlled website
• Injecting malicious content through advertising networks
• Embedding exploits in web pages visited by potential victims

The memory corruption could be triggered when Firefox processes specially crafted web content, potentially allowing attackers to execute arbitrary code with the privileges of the browser process.

Detection Methods for CVE-2024-5701

Indicators of Compromise

• Unexpected Firefox crashes or stability issues during web browsing
• Unusual memory consumption patterns in Firefox processes
• Evidence of exploit attempts in browser crash reports or telemetry data
• Anomalous network connections originating from Firefox processes

Detection Strategies

• Monitor endpoint detection and response (EDR) solutions for suspicious process behavior from Firefox
• Implement network security monitoring to detect known exploit delivery mechanisms
• Review system logs for unexpected child processes spawned by Firefox
• Deploy SentinelOne Singularity platform to detect post-exploitation behavior and memory-based attacks

Monitoring Recommendations

• Enable crash reporting and review Firefox crash telemetry for signs of exploitation attempts
• Monitor for unusual system calls or API usage from browser processes
• Implement browser isolation technologies for high-risk browsing scenarios
• Track Firefox version deployments across the organization to identify vulnerable instances

How to Mitigate CVE-2024-5701

Immediate Actions Required

• Update Mozilla Firefox to version 127 or later immediately
• Enable automatic updates in Firefox to ensure timely patching of future vulnerabilities
• Consider implementing browser isolation for sensitive operations until patching is complete
• Review and restrict browser plugin usage to reduce attack surface

Patch Information

Mozilla has addressed these memory safety vulnerabilities in Firefox 127. The security advisory MFSA-2024-25 provides official details about the fixes. Organizations should deploy Firefox 127 or later across all endpoints. The fix addresses the underlying memory safety issues tracked in Mozilla Bug Reports.

Workarounds

• If immediate patching is not possible, consider temporarily using an alternative browser for sensitive operations
• Implement network-level protections to block known malicious domains and exploit delivery mechanisms
• Enable browser sandboxing features and ensure they are not disabled
• Restrict JavaScript execution on untrusted websites using browser extensions or enterprise policies

# Firefox update verification on Linux
firefox --version
# Expected output should show version 127 or higher

# Check for available updates (varies by package manager)
# Debian/Ubuntu:
sudo apt update && sudo apt install firefox

# Fedora/RHEL:
sudo dnf update firefox