CVE-2022-2478: Google Chrome Use After Free Vulnerability

CVE-2022-2478 Overview

CVE-2022-2478 is a Use After Free vulnerability in the PDF component of Google Chrome prior to version 103.0.5060.134. This memory corruption flaw allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. When successfully exploited, an attacker can achieve arbitrary code execution with the privileges of the browser process.

Critical Impact

Remote attackers can achieve heap corruption and potentially execute arbitrary code by luring victims to malicious web pages containing crafted PDF content.

Affected Products

• Google Chrome versions prior to 103.0.5060.134
• Chromium-based browsers using the affected PDF rendering component
• Fedora Linux packages containing vulnerable Chrome versions

Discovery Timeline

• July 28, 2022 - CVE-2022-2478 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-2478

Vulnerability Analysis

This vulnerability (CWE-416) exists in the PDF rendering component of Google Chrome. Use After Free vulnerabilities occur when a program continues to use a pointer after the memory it references has been deallocated. In this case, the PDF component improperly handles memory during PDF rendering operations, creating a dangling pointer condition.

When Chrome processes a specially crafted HTML page containing malicious PDF content, the PDF rendering engine may free a memory object while other parts of the code still hold references to it. Subsequent operations that attempt to access this freed memory can lead to heap corruption, potentially allowing an attacker to overwrite critical data structures or execute arbitrary code.

The attack requires user interaction—specifically, the victim must navigate to a malicious webpage—but no special privileges are needed on the attacker's side. This network-accessible attack vector makes it particularly dangerous for drive-by attacks targeting unsuspecting users.

Root Cause

The root cause is improper memory lifecycle management within Chrome's PDF rendering component. The vulnerability stems from a failure to properly track object references before freeing memory, resulting in a dangling pointer that can be subsequently dereferenced. When the freed memory is reallocated for a different purpose, the stale pointer provides access to potentially attacker-controlled data, leading to heap corruption.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker can exploit this vulnerability by:

1. Crafting a malicious HTML page that embeds or references a specially designed PDF
2. Hosting the malicious page on a compromised or attacker-controlled website
3. Luring the victim to visit the page through phishing, social engineering, or malvertising
4. The vulnerable Chrome browser processes the malicious PDF content
5. The use-after-free condition triggers heap corruption
6. The attacker potentially achieves arbitrary code execution

The vulnerability does not require the attacker to have any prior access or privileges on the target system.

Detection Methods for CVE-2022-2478

Indicators of Compromise

• Unexpected Chrome browser crashes or instability when viewing PDF content
• Anomalous memory allocation patterns in Chrome processes
• Suspicious network traffic to unknown domains serving PDF-embedded HTML pages
• Browser process spawning unexpected child processes

Detection Strategies

• Monitor for Chrome crash reports indicating heap corruption or use-after-free conditions in PDF components
• Implement endpoint detection rules for anomalous browser behavior during PDF rendering
• Deploy network monitoring to detect connections to known malicious domains hosting exploit kits
• Use browser telemetry to track PDF rendering errors and memory violations

Monitoring Recommendations

• Enable Chrome's crash reporting and analyze crash dumps for indicators of exploitation attempts
• Implement browser extension policies that restrict PDF handling to trusted sources
• Monitor endpoint protection alerts for memory corruption indicators in browser processes
• Review web proxy logs for suspicious HTML pages with embedded PDF content

How to Mitigate CVE-2022-2478

Immediate Actions Required

• Update Google Chrome to version 103.0.5060.134 or later immediately
• Enable automatic updates in Chrome to receive future security patches promptly
• Consider using Chrome's Site Isolation feature to limit exploit impact
• Educate users about the risks of visiting untrusted websites

Patch Information

Google addressed this vulnerability in the Chrome Stable Channel Update released on July 19, 2022. Organizations should ensure all Chrome installations are updated to version 103.0.5060.134 or newer. For detailed information about the fix, refer to the Chrome Releases Blog and the Chromium Bug Report #1335861.

Fedora users should apply the security updates announced in the Fedora Package Announcements.

Workarounds

• Use an alternative PDF viewer application rather than Chrome's built-in PDF renderer
• Disable automatic PDF opening in Chrome by changing the "Download PDF files instead of automatically opening them in Chrome" setting
• Implement browser isolation solutions to sandbox potentially malicious content
• Use network security controls to block access to known malicious domains

# Configuration example: Disable automatic PDF opening in Chrome via policy
# For enterprise environments, deploy this Chrome policy:
# Create policy file: /etc/opt/chrome/policies/managed/pdf_policy.json

{
  "AlwaysOpenPdfExternally": true,
  "DownloadRestrictions": 1
}