CVE-2023-2359: Slider Revolution RCE Vulnerability

CVE-2023-2359 Overview

CVE-2023-2359 is an arbitrary file upload vulnerability affecting the Slider Revolution WordPress plugin through version 6.6.12. The plugin fails to properly validate image files during the import process, allowing attackers to upload malicious files that may be escalated to Remote Code Execution (RCE) depending on server configurations.

Critical Impact

Authenticated attackers can exploit this vulnerability to upload arbitrary files, potentially achieving remote code execution on vulnerable WordPress installations.

Affected Products

• Themepunch Slider Revolution versions through 6.6.12
• WordPress installations using vulnerable Slider Revolution plugin versions

Discovery Timeline

• June 19, 2023 - CVE-2023-2359 published to NVD
• December 12, 2024 - Last updated in NVD database

Technical Details for CVE-2023-2359

Vulnerability Analysis

This vulnerability stems from insufficient file validation in the Slider Revolution plugin's import functionality. When users import slider content, the plugin processes image files without properly verifying that the uploaded content is actually a valid image file. This lack of validation creates an opportunity for attackers to upload files with malicious content disguised as images.

The attack requires low privileges (authenticated user access) but can be executed remotely over the network without any user interaction. Successful exploitation can lead to complete compromise of confidentiality, integrity, and availability of the affected WordPress installation.

Root Cause

The root cause is classified as CWE-94 (Improper Control of Generation of Code), also known as Code Injection. The Slider Revolution plugin's import mechanism lacks proper file type validation, allowing arbitrary file types to be uploaded through the image import process. This occurs because the plugin trusts user-supplied file extensions or MIME types without performing thorough content inspection.

Attack Vector

The attack is network-based and can be carried out by an authenticated user with access to the Slider Revolution import functionality. An attacker crafts a malicious file (such as a PHP web shell) and uploads it through the slider import feature. Because the plugin does not validate file contents, the malicious file is stored on the server. Depending on server configuration, the attacker may then access this uploaded file directly, triggering code execution.

The vulnerability exploitation flow involves:

1. Authenticating to the WordPress installation with privileges to use Slider Revolution
2. Accessing the slider import functionality
3. Uploading a crafted malicious file disguised as an image
4. Locating and accessing the uploaded file on the server
5. Achieving code execution if the server processes the uploaded file

Detection Methods for CVE-2023-2359

Indicators of Compromise

• Unusual file uploads in WordPress media directories or Slider Revolution plugin folders
• PHP files or other executable scripts appearing in image upload directories
• Unexpected web shells or backdoor files in the wp-content/uploads/ directory structure
• Suspicious POST requests to Slider Revolution import endpoints with unusual file contents

Detection Strategies

• Monitor file system changes for new PHP files in WordPress upload directories
• Implement Web Application Firewall (WAF) rules to detect file upload attempts with mismatched MIME types and content
• Review server logs for access patterns to uploaded files, especially recently created files in plugin directories
• Scan WordPress installations for known web shell signatures and suspicious file extensions

Monitoring Recommendations

• Enable file integrity monitoring on the WordPress installation directory
• Configure alerts for new executable files created in web-accessible directories
• Implement logging for all Slider Revolution import operations
• Regularly audit user accounts with privileges to access Slider Revolution functionality

How to Mitigate CVE-2023-2359

Immediate Actions Required

• Update Slider Revolution plugin to the latest version available beyond 6.6.12
• Review and restrict user permissions for Slider Revolution import functionality
• Audit existing uploaded files for suspicious content or unexpected file types
• Implement server-side restrictions to prevent execution of uploaded files

Patch Information

Update the Slider Revolution WordPress plugin to the latest patched version. For detailed vulnerability information, refer to the WPScan Vulnerability Report.

Workarounds

• Temporarily disable the Slider Revolution import functionality until the plugin is updated
• Restrict access to Slider Revolution administration features to trusted administrators only
• Configure the web server to prevent execution of PHP files in upload directories
• Implement additional file validation at the server level using .htaccess or nginx configuration rules

# Apache configuration to prevent PHP execution in uploads directory
# Add to .htaccess in wp-content/uploads/
<FilesMatch "\.(?:php|phtml|php[3-7]?|pht)$">
    Order Allow,Deny
    Deny from all
</FilesMatch>