CVE-2020-16037: Google Chrome Use After Free Vulnerability

CVE-2020-16037 Overview

CVE-2020-16037 is a use after free vulnerability in the clipboard component of Google Chrome prior to version 87.0.4280.88. This memory corruption flaw allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. The vulnerability stems from improper memory management in the clipboard functionality, where memory is accessed after it has been freed, leading to undefined behavior and potential code execution.

Critical Impact

Remote attackers can exploit this heap corruption vulnerability through maliciously crafted web pages, potentially leading to arbitrary code execution within the browser context.

Affected Products

• Google Chrome versions prior to 87.0.4280.88

Discovery Timeline

• 2021-01-08 - CVE-2020-16037 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-16037

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a critical memory corruption issue that occurs when a program continues to use a pointer after the memory it references has been freed. In the context of Google Chrome's clipboard component, this flaw enables attackers to corrupt heap memory through specially crafted HTML content.

The attack requires user interaction, specifically requiring the victim to visit a malicious web page. Once the page is loaded, the crafted HTML can trigger the use after free condition in the clipboard handling code. Successful exploitation could allow an attacker to achieve arbitrary code execution with the privileges of the user running the browser, potentially compromising confidentiality, integrity, and availability of the affected system.

Root Cause

The root cause of CVE-2020-16037 lies in improper memory lifecycle management within Chrome's clipboard component. When clipboard operations are performed, the browser allocates memory to handle clipboard data. The vulnerability occurs when this memory is freed but a dangling pointer remains, which is subsequently dereferenced during later clipboard operations. This dangling pointer access can corrupt heap memory structures, creating an exploitable condition.

Attack Vector

The attack is network-based and requires the victim to navigate to an attacker-controlled or compromised website hosting a malicious HTML page. The attacker crafts HTML content designed to trigger specific clipboard operations that exploit the use after free condition. When the victim interacts with the page or the clipboard functionality is automatically invoked, the vulnerability is triggered.

The exploitation chain typically involves:

1. Victim visits a malicious web page
2. JavaScript or HTML triggers clipboard operations
3. Memory corruption occurs due to the use after free condition
4. Attacker gains control over program execution flow

The vulnerability manifests in the clipboard memory management routines within Chrome. For technical details, see the Chromium Bug Report #1142331 and the Google Chrome Update Announcement.

Detection Methods for CVE-2020-16037

Indicators of Compromise

• Unusual browser crashes or unexpected behavior during clipboard operations
• Detection of heap corruption patterns in Chrome crash dumps
• Suspicious web pages containing heavily obfuscated JavaScript targeting clipboard functionality
• Memory access violations logged in system event logs related to Chrome processes

Detection Strategies

• Monitor for Chrome version strings below 87.0.4280.88 across endpoint fleet
• Implement web filtering to detect and block known malicious domains serving exploit pages
• Deploy memory protection solutions capable of detecting heap corruption attempts
• Use browser-based threat detection to identify suspicious clipboard API usage patterns

Monitoring Recommendations

• Enable Chrome crash reporting and analyze crash dumps for use after free signatures
• Monitor network traffic for connections to suspicious domains serving crafted HTML content
• Implement endpoint detection and response (EDR) solutions to detect exploitation attempts
• Review browser telemetry for anomalous clipboard-related activities

How to Mitigate CVE-2020-16037

Immediate Actions Required

• Update Google Chrome to version 87.0.4280.88 or later immediately
• Enable automatic updates for Chrome to ensure timely security patch deployment
• Audit all endpoints to identify and remediate vulnerable Chrome installations
• Consider temporary network-level blocking of suspicious domains until patching is complete

Patch Information

Google has addressed this vulnerability in Chrome version 87.0.4280.88, released in December 2020. The fix resolves the improper memory management in the clipboard component that led to the use after free condition.

Patch details are available in the Google Chrome Stable Channel Update announcement. Organizations should verify all Chrome installations are updated to this version or later.

Workarounds

• Use alternative browsers until Chrome can be updated in environments where immediate patching is not possible
• Implement browser isolation solutions to contain potential exploitation attempts
• Restrict access to untrusted websites through web filtering proxies
• Deploy application whitelisting to limit execution of potentially malicious code

# Verify Chrome version on Linux/macOS
google-chrome --version

# On Windows, check Chrome version via registry
reg query "HKEY_CURRENT_USER\Software\Google\Chrome\BLBeacon" /v version

# Force Chrome update on enterprise deployments
# Ensure Chrome is configured to update automatically