CVE-2023-4088 Overview
CVE-2023-4088 is an Incorrect Default Permissions vulnerability affecting multiple Mitsubishi Electric Corporation Factory Automation (FA) engineering software products. This vulnerability allows a malicious local attacker to execute arbitrary code, potentially resulting in information disclosure, data tampering and deletion, or a denial-of-service (DoS) condition. The vulnerability is triggered when the affected product is installed in a folder other than the default installation folder.
Critical Impact
Local attackers can exploit incorrect default permissions to execute malicious code, leading to complete compromise of confidentiality, integrity, and availability of industrial control system engineering environments.
Affected Products
- Mitsubishi Electric GX Works3 (all versions when installed in non-default folders)
- Mitsubishi Electric FA engineering software products
Discovery Timeline
- 2023-09-20 - CVE-2023-4088 published to NVD
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2023-4088
Vulnerability Analysis
This vulnerability stems from CWE-276 (Incorrect Default Permissions), a configuration and design flaw where the software installation process does not properly configure access control permissions on directories when the product is installed to a non-default location. When FA engineering software is installed outside the standard Program Files directory, the installer may fail to apply appropriate ACLs (Access Control Lists), leaving the installation directory with overly permissive settings.
In industrial control system (ICS) environments, FA engineering software like GX Works3 is critical for programming and maintaining programmable logic controllers (PLCs). Compromise of such software can have cascading effects on the physical processes controlled by these systems.
Root Cause
The root cause of CVE-2023-4088 lies in the installation routine's failure to properly set restrictive file system permissions when users choose a custom installation path. Windows operating systems typically apply more restrictive permissions to the Program Files directory by default. However, when users install software to alternative locations such as C:\CustomApps\ or other user-writable directories, the installer does not explicitly configure appropriate access controls, inheriting the less restrictive parent directory permissions instead.
Attack Vector
The attack requires local access to the system where the vulnerable Mitsubishi Electric software is installed. An attacker with low-privilege local access can exploit this vulnerability by:
- Identifying installations of affected FA engineering software in non-default directories
- Locating executable files, DLLs, or configuration files within the installation directory
- Replacing legitimate files with malicious versions due to weak permissions
- Waiting for the legitimate user or scheduled task to execute the compromised software
Since FA engineering software often runs with elevated privileges to communicate with industrial hardware, successful exploitation can provide the attacker with significant control over the engineering workstation and potentially connected industrial systems.
The vulnerability mechanism involves improper permission handling during non-default installations. When the software is installed to a custom directory path, the installer fails to apply restrictive ACLs. This allows authenticated local users to modify or replace critical application files. Technical details are available in the Mitsubishi Electric Security Advisory.
Detection Methods for CVE-2023-4088
Indicators of Compromise
- Unexpected modifications to executable files, DLLs, or scripts within the GX Works3 installation directory
- File timestamps on critical binaries that do not match expected installation or update dates
- Presence of unsigned or improperly signed executables in the application directory
- Unusual process execution originating from the FA engineering software installation path
Detection Strategies
- Monitor file integrity of Mitsubishi Electric FA engineering software installations using host-based integrity monitoring tools
- Audit Windows Security Event Logs for file modification events (Event ID 4663) targeting the GX Works3 installation directory
- Implement application whitelisting to detect unauthorized executables running from the software installation path
- Review directory ACLs on systems with non-default installations to identify overly permissive configurations
Monitoring Recommendations
- Deploy endpoint detection and response (EDR) solutions like SentinelOne to monitor for suspicious file modifications and process behavior
- Configure Windows Advanced Audit Policy to log object access events on FA engineering software directories
- Establish baseline file hashes for all critical GX Works3 components and alert on deviations
- Monitor for privilege escalation attempts originating from processes in the affected installation directories
How to Mitigate CVE-2023-4088
Immediate Actions Required
- Verify installation locations of all Mitsubishi Electric FA engineering software and identify any non-default installations
- Manually review and correct file system permissions on non-default installation directories to restrict write access to administrators only
- Apply the latest security updates from Mitsubishi Electric as described in their security advisory
- Consider reinstalling affected software to the default installation directory with proper permissions
Patch Information
Mitsubishi Electric has released security guidance addressing this vulnerability. Organizations should consult the official Mitsubishi Electric security advisory for specific patch information and updated software versions. Additionally, CISA ICS Advisory ICSA-23-269-03 provides supplementary guidance for industrial control system operators.
Workarounds
- Install FA engineering software only to the default installation directory under Program Files
- Manually configure restrictive NTFS permissions on non-default installation directories, removing write access for non-administrative users
- Implement application whitelisting to prevent execution of unauthorized binaries
- Isolate engineering workstations on dedicated network segments with restricted access
# Windows command to restrict permissions on non-default installation directory
# Run as Administrator to secure a custom installation path
icacls "C:\CustomPath\GX Works3" /inheritance:r /grant:r Administrators:(OI)(CI)F /grant:r SYSTEM:(OI)(CI)F /grant:r Users:(OI)(CI)RX
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
