CVE-2024-50496: Webandprint AR RCE Vulnerability

CVE-2024-50496 Overview

CVE-2024-50496 is an Unrestricted Upload of File with Dangerous Type vulnerability affecting the AR For WordPress plugin by Web and Print Design. This vulnerability allows unauthenticated attackers to upload arbitrary files, including web shells, directly to the web server. The flaw exists because the plugin fails to properly validate file types during the upload process, enabling attackers to bypass security controls and execute malicious code on the target WordPress installation.

Critical Impact

This vulnerability enables unauthenticated remote attackers to upload and execute web shells on vulnerable WordPress sites, potentially leading to complete server compromise, data exfiltration, and lateral movement within the hosting environment.

Affected Products

• AR For WordPress plugin versions from n/a through 6.2
• WordPress installations running vulnerable versions of the AR For WordPress plugin
• Web servers hosting affected WordPress sites

Discovery Timeline

• 2024-10-28 - CVE-2024-50496 published to NVD
• 2024-11-08 - Last updated in NVD database

Technical Details for CVE-2024-50496

Vulnerability Analysis

This vulnerability is classified as CWE-434 (Unrestricted Upload of File with Dangerous Type). The AR For WordPress plugin fails to implement adequate file type validation during the file upload process. Without proper restrictions on uploadable file types, attackers can upload executable scripts such as PHP web shells directly to the server.

The impact of this vulnerability is severe. Once a web shell is successfully uploaded, an attacker gains the ability to execute arbitrary commands on the server with the privileges of the web server process. This can lead to complete compromise of the WordPress installation, access to sensitive configuration files including database credentials, modification or deletion of website content, and potential pivoting to other systems on the same network.

Root Cause

The root cause of CVE-2024-50496 lies in the plugin's failure to properly validate and restrict file types during upload operations. The plugin accepts file uploads without verifying that the uploaded content matches allowed, safe file types. This lack of validation allows attackers to upload files with dangerous extensions such as .php, .phtml, or other server-side executable formats.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker can exploit this vulnerability remotely by sending a specially crafted HTTP request to the vulnerable upload endpoint. The attack flow typically involves:

1. Identifying a WordPress site running the vulnerable AR For WordPress plugin
2. Crafting an HTTP request containing a malicious PHP file disguised or uploaded directly
3. Uploading the web shell to an accessible directory on the server
4. Accessing the uploaded file via HTTP to execute commands

The vulnerability does not require any privileges to exploit, making it particularly dangerous as any remote attacker can target vulnerable installations. The scope is changed, meaning a successful exploit can affect resources beyond the vulnerable component itself, potentially compromising the entire web server and hosting environment.

Detection Methods for CVE-2024-50496

Indicators of Compromise

• Unexpected PHP files appearing in WordPress upload directories, particularly within the wp-content/uploads folder or plugin-specific directories
• Web server access logs showing requests to unusual file paths containing recently uploaded PHP files
• Suspicious outbound network connections originating from the web server process
• Unexpected system commands being executed by the web server user account

Detection Strategies

• Monitor file creation events in WordPress directories for newly created PHP or other executable script files
• Implement web application firewall (WAF) rules to detect and block file upload requests containing executable content
• Review web server access logs for requests to non-standard PHP files in upload directories
• Deploy file integrity monitoring to alert on unauthorized file additions to the WordPress installation

Monitoring Recommendations

• Enable detailed logging for all HTTP POST requests to WordPress upload endpoints
• Configure alerting for any new executable files created in web-accessible directories
• Monitor for anomalous process spawning from web server processes (Apache, Nginx, PHP-FPM)
• Implement network monitoring to detect command and control communications from compromised servers

How to Mitigate CVE-2024-50496

Immediate Actions Required

• Immediately deactivate and remove the AR For WordPress plugin from all WordPress installations until a patched version is available
• Audit WordPress upload directories for any suspicious or unexpected PHP files
• Review web server access logs for evidence of exploitation attempts
• Consider implementing additional access controls at the web server level to restrict upload functionality

Patch Information

As of the last NVD update on 2024-11-08, users should consult the Patchstack vulnerability database entry for the latest remediation guidance and patch availability. Contact the plugin vendor, Web and Print Design, for information about updated versions that address this vulnerability.

Workarounds

• Remove the AR For WordPress plugin entirely if it is not critical to site functionality
• Implement server-level file upload restrictions to block executable file types from being uploaded
• Configure .htaccess rules to prevent PHP execution in upload directories
• Deploy a web application firewall with rules specifically targeting malicious file uploads

# Apache .htaccess configuration to prevent PHP execution in uploads directory
# Add this to wp-content/uploads/.htaccess

<FilesMatch "\.(?:php|phtml|php[3-7]|pht)$">
    Require all denied
</FilesMatch>

# Alternative: Disable PHP engine entirely in uploads
php_flag engine off