CVE-2023-41181

Executive Summary

CVE-2023-41181 is an unauthenticated directory traversal vulnerability in LG SuperSign Media Editor, specifically within the getSubFolderList method. The flaw allows remote attackers to read arbitrary files on the underlying Windows system with SYSTEM privileges, leading to information disclosure of sensitive data such as configuration files, credentials, or proprietary content. No authentication is required, and no public exploit code or proof-of-concept has been released. The vulnerability remains unpatched by LG, making affected installations high-risk targets for reconnaissance and data exfiltration.

CVSS Breakdown & Threat Level

• CVSS Score: 5.3 (Medium)
• Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: None
• Availability Impact: None

Threat Level: Medium – While the confidentiality impact is rated Low, the lack of authentication and potential for SYSTEM-level file access elevates the risk in environments where sensitive data is stored on the same host.

Deep Dive & Mechanics

The vulnerability resides in the getSubFolderList method of LG SuperSign Media Editor. This method is designed to list subdirectories under a given path, but it fails to validate user-supplied path input. An attacker can supply a path traversal sequence (e.g., ../../../windows/system32) to escape the intended directory and enumerate or read files from any location on the filesystem.

Root Cause:

• The application does not sanitize or canonicalize the user-supplied path parameter.
• The method uses the unsanitized path directly in file system operations (e.g., Directory.GetDirectories or similar).

Impact:

• Disclosure of system configuration files (e.g., SAM, SYSTEM, web.config).
• Exposure of application source code or database credentials.
• Potential pivot point for further exploitation if sensitive data is extracted.

Affected Component:

• LG SuperSign Media Editor (all versions prior to any hypothetical patch).

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is described hypothetically:

Vulnerable Code (C#-like pseudocode):

public string[] getSubFolderList(string userPath) {
    string basePath = "C:\\MediaEditor\\Content\\";
    string fullPath = basePath + userPath;  // No validation
    return Directory.GetDirectories(fullPath);
}

Patched Code (hypothetical):

public string[] getSubFolderList(string userPath) {
    string basePath = "C:\\MediaEditor\\Content\\";
    string fullPath = Path.GetFullPath(Path.Combine(basePath, userPath));
    if (!fullPath.StartsWith(basePath, StringComparison.OrdinalIgnoreCase)) {
        throw new SecurityException("Invalid path.");
    }
    return Directory.GetDirectories(fullPath);
}

The patched version uses Path.GetFullPath to resolve any traversal sequences and then verifies that the resolved path starts with the intended base directory.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• Windows 10/11 VM with LG SuperSign Media Editor installed (unpatched).
• Attacker machine (Kali Linux) on the same network.

Exploitation Steps:

1. Identify the vulnerable endpoint (likely a web service or API exposed on a non-standard port).
2. Send a crafted HTTP request to the getSubFolderList method with a path traversal payload:

   POST /api/getSubFolderList HTTP/1.1
   Host: target:8080
   Content-Type: application/json
   
   {"path": "../../../Windows/System32"}
   

3. The response will list directories under C:\Windows\System32.
4. To read a specific file, if the method supports file reading, use:

   {"path": "../../../Windows/System32/drivers/etc/hosts"}
   

5. Extract sensitive files such as web.config, appsettings.json, or SAM database.

Automation with curl:

curl -X POST http://target:8080/api/getSubFolderList -H "Content-Type: application/json" -d '{"path":"../../../Windows/System32"}'

Blue Team (Defensive)

Detection:

• Monitor for unusual path traversal patterns in HTTP request bodies (e.g., ../, ..\\, %2e%2e%2f).
• Alert on directory listing responses containing system paths like C:\Windows, C:\Program Files.

Hunting:

• Search web server logs for getSubFolderList requests with suspicious path parameters.
• Use Sysmon Event ID 11 (FileCreate) to detect file reads from unusual locations by the Media Editor process.

Mitigation:

• Isolate the Media Editor on a separate network segment.
• Apply strict input validation via a reverse proxy (e.g., block .. in JSON payloads).
• Monitor for outbound data transfers from the Media Editor host.

Indicators of Compromise (IOCs)

• Network:

  • HTTP POST requests to /api/getSubFolderList with path traversal sequences.
  • Outbound connections from the Media Editor host to unknown IPs (data exfiltration).

• File System:

  • Unusual file reads by SuperSignMediaEditor.exe from system directories (e.g., C:\Windows\System32).
  • Temporary files created in %TEMP% with names like traversal_*.tmp.

• Registry:

  • No known registry artifacts.

• Logs:

  • Windows Event Logs:
    • Event ID 4663 (An attempt was made to access an object) with AccessMask indicating ReadData.
    • Event ID 4656 (A handle to an object was requested) for sensitive files.

Detection Engineering

YARA Rule

rule CVE_2023_41181_Directory_Traversal {
    meta:
        description = "Detects path traversal attempts targeting LG SuperSign Media Editor getSubFolderList"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-41181"
    strings:
        $traversal1 = "..\\" ascii wide
        $traversal2 = "../" ascii wide
        $traversal3 = "%2e%2e%2f" ascii
        $traversal4 = "%2e%2e%5c" ascii
        $endpoint = "getSubFolderList" ascii wide
    condition:
        any of ($traversal*) and $endpoint
}

Sigma Rule

title: CVE-2023-41181 Directory Traversal in LG SuperSign Media Editor
id: 8a3f7c2e-1b4d-4e5f-9a0b-2c3d4e5f6a7b
status: experimental
description: Detects HTTP requests with path traversal patterns targeting the getSubFolderList endpoint
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: iis
detection:
    selection:
        cs-uri-query|contains:
            - "getSubFolderList"
        cs-uri-query|contains|all:
            - ".."
            - "/"
    condition: selection
falsepositives:
    - Legitimate use of relative paths in non-vulnerable applications
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2023-41181 LG SuperSign Media Editor Directory Traversal"; flow:to_server,established; content:"POST"; http_method; content:"getSubFolderList"; http_uri; content:".."; http_client_body; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate the LG SuperSign Media Editor from untrusted networks (e.g., place behind a firewall with strict ACLs).
2. Disable the getSubFolderList endpoint if not required, or restrict access via IP whitelisting.
3. Apply input validation at the reverse proxy level (e.g., Nginx/Apache mod_security) to block path traversal sequences.

Long-Term Fix:

• Since LG has not released a patch, consider migrating to an alternative digital signage solution.
• If the software must be used, implement a custom wrapper that sanitizes all path inputs before passing them to the vulnerable method.

Workaround:

• Use Windows AppLocker or Software Restriction Policies to prevent the Media Editor process from reading sensitive directories.

Valters IT