CVE-2020-6507: Google Chrome V8 RCE Vulnerability

CVE-2020-6507 Overview

CVE-2020-6507 is an out-of-bounds write vulnerability in the V8 JavaScript engine used by Google Chrome prior to version 83.0.4103.106. This vulnerability allows a remote attacker to potentially exploit heap corruption via a crafted HTML page, enabling remote code execution on affected systems.

Critical Impact

Remote attackers can execute arbitrary code on victim systems by convincing users to visit a malicious website containing specially crafted JavaScript code that triggers the V8 heap corruption.

Affected Products

• Google Chrome versions prior to 83.0.4103.106
• Chromium-based browsers using vulnerable V8 engine versions
• Systems running Google Chrome on all supported platforms (Windows, macOS, Linux)

Discovery Timeline

• 2020-07-22 - CVE-2020-6507 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-6507

Vulnerability Analysis

This vulnerability resides in V8, Google Chrome's high-performance JavaScript and WebAssembly engine. The flaw involves an out-of-bounds write condition that can corrupt heap memory when processing maliciously crafted JavaScript code. The vulnerability classification under CWE-20 (Improper Input Validation) indicates that the root cause stems from insufficient validation of input data before it is processed by the V8 engine.

Successful exploitation enables remote code execution, meaning an attacker can take complete control of an affected system. The vulnerability requires user interaction—specifically, a victim must navigate to an attacker-controlled webpage or be redirected to one. Once the malicious page is loaded, the exploit triggers without additional user interaction.

Public exploit code is available through Packet Storm Security, demonstrating real-world exploitability. This makes the vulnerability particularly dangerous as threat actors have access to functional exploitation techniques.

Root Cause

The vulnerability originates from improper input validation (CWE-20) within the V8 JavaScript engine's memory handling routines. When processing certain JavaScript operations, the engine fails to properly validate array indices or object boundaries, resulting in writes to memory locations outside the intended buffer. This heap corruption can then be leveraged to achieve arbitrary code execution by carefully manipulating the memory layout.

Attack Vector

The attack is delivered over the network through a web-based vector. An attacker creates a malicious webpage containing crafted JavaScript code designed to trigger the out-of-bounds write condition in V8. The attack sequence typically follows this pattern:

1. Attacker hosts or injects malicious JavaScript on a webpage
2. Victim navigates to the malicious page (via phishing, malvertising, or compromised legitimate sites)
3. Chrome's V8 engine processes the JavaScript, triggering the heap corruption
4. Attacker achieves code execution with the privileges of the browser process
5. Further exploitation may include sandbox escape or persistence mechanisms

Detailed technical information regarding exploitation techniques can be found in the Packet Storm RCE Exploit publication.

Detection Methods for CVE-2020-6507

Indicators of Compromise

• Unusual Chrome crash patterns, particularly those involving V8 or JavaScript execution
• Unexpected child processes spawned by Chrome browser processes
• Network connections to known malicious domains hosting exploit code
• Memory access violations or heap corruption events logged by endpoint protection

Detection Strategies

• Monitor for anomalous JavaScript execution patterns and memory allocation behaviors in browser processes
• Deploy endpoint detection rules targeting heap spray techniques commonly used in browser exploits
• Implement network-based detection for known exploit delivery infrastructure
• Utilize browser telemetry to identify crashes associated with V8 engine failures

Monitoring Recommendations

• Enable Chrome's built-in crash reporting to identify potential exploitation attempts
• Monitor system logs for unusual process behavior following browser sessions
• Deploy SentinelOne Singularity to detect behavioral indicators of post-exploitation activity
• Track browser version deployments across the organization to identify vulnerable installations

How to Mitigate CVE-2020-6507

Immediate Actions Required

• Update Google Chrome to version 83.0.4103.106 or later immediately
• Enable automatic Chrome updates to ensure timely patching of future vulnerabilities
• Implement browser isolation technologies for high-risk browsing activities
• Deploy endpoint protection capable of detecting exploit-based attacks

Patch Information

Google released a security patch in Chrome version 83.0.4103.106 that addresses this vulnerability. The fix was announced in the Google Chrome Release Update on June 15, 2020. Organizations should verify that all Chrome installations have been updated to this version or later.

Additional security guidance is available through the Gentoo GLSA 202007-08 for Linux distributions. The original bug report can be tracked via the Chrome Bug Tracker Entry.

Workarounds

• Disable JavaScript execution for untrusted websites using Chrome's site settings
• Use browser extensions that provide script blocking capabilities (e.g., NoScript, uBlock Origin)
• Implement web content filtering to block access to known malicious domains
• Consider using alternative browsers until patching can be completed in enterprise environments

# Verify Chrome version to ensure patch is applied
google-chrome --version
# Expected output should show version 83.0.4103.106 or higher

# Force Chrome update check on Linux systems
sudo apt update && sudo apt upgrade google-chrome-stable

# Enterprise deployment: Use Chrome policies to enforce automatic updates
# Create or modify /etc/opt/chrome/policies/managed/update_policy.json
echo '{"AutoUpdateCheckPeriodMinutes": 60}' | sudo tee /etc/opt/chrome/policies/managed/update_policy.json