CVE-2023-4068: Google Chrome V8 Type Confusion RCE Flaw

CVE-2023-4068 Overview

CVE-2023-4068 is a type confusion vulnerability in the V8 JavaScript engine used by Google Chrome prior to version 115.0.5790.170. This vulnerability allows a remote attacker to perform arbitrary read and write operations via a crafted HTML page, potentially leading to full browser compromise.

Critical Impact

Remote attackers can achieve arbitrary memory read/write capabilities through a malicious web page, potentially enabling code execution within the browser sandbox or further exploitation.

Affected Products

• Google Chrome versions prior to 115.0.5790.170
• Chromium-based browsers using vulnerable V8 engine versions
• Linux distributions shipping affected Chrome/Chromium packages (Debian, Fedora, Gentoo)

Discovery Timeline

• 2023-08-03 - CVE-2023-4068 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-4068

Vulnerability Analysis

This vulnerability stems from a type confusion issue (CWE-843) within the V8 JavaScript engine, Chrome's high-performance JavaScript and WebAssembly engine. Type confusion vulnerabilities occur when code does not verify the type of an object it receives and uses it as a different type than intended, leading to memory corruption.

In this case, the V8 engine incorrectly handles certain JavaScript objects, allowing an attacker to confuse the engine about the true type of an object in memory. This confusion enables the attacker to access memory regions that should be off-limits, achieving arbitrary read and write primitives. Such primitives are foundational building blocks for more sophisticated attacks, including remote code execution.

The attack requires user interaction—specifically, the victim must navigate to a malicious HTML page crafted by the attacker. The vulnerability is network-exploitable with no authentication required, making it suitable for drive-by download attacks or watering hole campaigns.

Root Cause

The root cause is improper type verification within the V8 JavaScript engine's Just-In-Time (JIT) compilation or object handling routines. When the engine processes certain JavaScript constructs, it fails to properly validate object types before performing operations, leading to type confusion. This allows attackers to craft JavaScript code that manipulates the engine into treating one object type as another, corrupting memory structures and gaining unauthorized memory access.

Attack Vector

The attack is delivered via a network vector, where an attacker hosts or injects malicious JavaScript into a web page. When a victim visits the compromised page using a vulnerable version of Google Chrome:

1. The malicious JavaScript executes within the browser's V8 engine
2. The crafted code triggers the type confusion condition
3. The attacker gains arbitrary read/write capabilities in the renderer process
4. This primitive can be chained with sandbox escape techniques for full system compromise

The vulnerability does not impact availability according to the CVSS vector, but the confidentiality and integrity impacts are high, meaning attackers can both read sensitive data and modify memory contents.

Detection Methods for CVE-2023-4068

Indicators of Compromise

• Unexpected browser crashes or hangs when visiting specific websites
• Anomalous V8 engine behavior or JavaScript execution patterns
• Suspicious outbound network connections following webpage visits
• Evidence of renderer process memory corruption in crash dumps

Detection Strategies

• Monitor for Chrome crash reports indicating V8-related failures
• Deploy browser version auditing to identify unpatched Chrome installations
• Implement network-level detection for known malicious JavaScript patterns
• Review endpoint detection logs for suspicious Chrome process behavior

Monitoring Recommendations

• Enable Chrome's crash reporting and monitor for V8-related crashes
• Audit browser versions across the enterprise to ensure Chrome 115.0.5790.170 or later is deployed
• Monitor security advisories from Google and downstream distributions (Debian, Fedora, Gentoo)
• Implement web filtering to block access to known malicious domains

How to Mitigate CVE-2023-4068

Immediate Actions Required

• Update Google Chrome to version 115.0.5790.170 or later immediately
• Enable automatic Chrome updates to ensure timely patching
• Update Chromium-based browsers (Edge, Brave, Opera) that may use affected V8 versions
• Consider deploying browser isolation solutions for high-risk users

Patch Information

Google has released a security update addressing this vulnerability in Chrome version 115.0.5790.170. The fix was announced via the Chrome Releases Blog. Linux distributions have also issued advisories and patches:

• Debian Security Advisory DSA-5467
• Fedora Package Announcement
• Gentoo GLSA 202311-11
• Gentoo GLSA 202312-07
• Gentoo GLSA 202401-34

Workarounds

• Disable JavaScript execution in Chrome via settings (significantly impacts usability)
• Use browser isolation or virtual browser solutions for untrusted web content
• Implement strict content security policies blocking inline JavaScript where possible
• Consider using alternative browsers for accessing untrusted websites until patching is complete

# Verify Chrome version on Linux
google-chrome --version
# Expected output should be 115.0.5790.170 or higher

# Force Chrome update check
google-chrome --check-for-update-interval=1