CVE-2023-3739: Google Chrome RCE Vulnerability

CVE-2023-3739 Overview

CVE-2023-3739 is a command injection vulnerability affecting Google Chrome on ChromeOS caused by insufficient validation of untrusted input in the Chromad component. This flaw allows a remote attacker to execute arbitrary code via a crafted shell script on vulnerable ChromeOS devices running versions prior to 115.0.5790.131.

Critical Impact

Remote attackers can execute arbitrary code on ChromeOS devices through crafted shell scripts, potentially leading to complete system compromise, data theft, or lateral movement within enterprise environments.

Affected Products

• Google Chrome on ChromeOS prior to version 115.0.5790.131
• Google ChromeOS (all versions prior to the security patch)

Discovery Timeline

• 2023-08-01 - CVE-2023-3739 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-3739

Vulnerability Analysis

The vulnerability resides in the Chromad component of Google Chrome on ChromeOS, a daemon responsible for system management and communication between Chrome browser and the underlying operating system. The flaw stems from insufficient validation of untrusted input (CWE-77: Improper Neutralization of Special Elements used in a Command), which allows attackers to inject malicious shell commands.

Chromad processes external input that can influence shell command execution. When user-controlled data is incorporated into shell commands without proper sanitization, an attacker can craft malicious input containing shell metacharacters or command sequences that get executed with the privileges of the Chromad process.

The attack requires user interaction, such as visiting a malicious website or opening a crafted file that triggers the vulnerable code path. Upon successful exploitation, the attacker gains the ability to execute arbitrary commands on the target ChromeOS system.

Root Cause

The root cause of CVE-2023-3739 is improper neutralization of special elements used in command construction. The Chromad component fails to adequately validate or sanitize untrusted input before incorporating it into shell commands, allowing command injection attacks. This represents a classic CWE-77 vulnerability where shell metacharacters and command separators in user input are not properly escaped or filtered.

Attack Vector

This vulnerability is exploitable remotely over the network. An attacker must craft a malicious shell script or input payload designed to exploit the insufficient input validation in Chromad. The attack requires user interaction—the victim must perform an action such as visiting a malicious website, clicking a link, or opening a crafted file that triggers the vulnerable code path.

Once the malicious input reaches the Chromad component, the injected shell commands execute on the target system, potentially allowing the attacker to gain unauthorized access, exfiltrate data, install malware, or perform other malicious actions with the privileges of the affected process.

The vulnerability mechanism involves crafted shell script content that bypasses input validation and achieves code execution. For technical details, refer to the Chromium Bug Report #1398986.

Detection Methods for CVE-2023-3739

Indicators of Compromise

• Unexpected shell processes spawned by Chromad or Chrome-related processes
• Unusual network connections originating from ChromeOS devices to unknown external hosts
• Suspicious command-line arguments in process logs containing shell metacharacters or encoded payloads
• Unexpected file modifications or new files created in system directories

Detection Strategies

• Monitor process creation events for unusual child processes spawned by Chromad
• Implement endpoint detection rules to identify shell command injection patterns in process arguments
• Deploy network monitoring to detect anomalous outbound connections from ChromeOS devices
• Review Chrome and ChromeOS logs for signs of exploitation attempts

Monitoring Recommendations

• Enable detailed logging for Chromad and related ChromeOS system components
• Configure SentinelOne agents to monitor for command injection attack patterns on ChromeOS endpoints
• Set up alerts for any shell execution anomalies associated with Chrome browser processes
• Regularly audit ChromeOS device versions to ensure patch compliance

How to Mitigate CVE-2023-3739

Immediate Actions Required

• Update all affected ChromeOS devices to version 115.0.5790.131 or later immediately
• Implement network segmentation to limit potential lateral movement from compromised devices
• Review and audit ChromeOS device inventory to identify vulnerable systems
• Enable enhanced monitoring on ChromeOS endpoints pending patch deployment

Patch Information

Google has addressed this vulnerability in ChromeOS version 115.0.5790.131. Organizations should apply the update through their standard ChromeOS device management processes. The security patch is documented in the Google ChromeOS Update Blog.

For enterprise environments, administrators should push the update through the Google Admin Console to ensure all managed ChromeOS devices receive the security fix promptly.

Workarounds

• Limit user access to untrusted websites and downloads until patches are applied
• Implement strict web content filtering policies to reduce exposure to malicious content
• Consider temporarily restricting ChromeOS device network access in high-security environments
• Educate users about avoiding suspicious links and files that could trigger exploitation

# Verify ChromeOS version via command line
# Navigate to chrome://system on the affected device
# Ensure version is 115.0.5790.131 or higher

# For enterprise deployment, use Google Admin Console to enforce updates:
# Admin Console > Devices > Chrome > Settings > Device update settings
# Set "Auto-update settings" to update devices automatically