CVE-2025-49907

Executive Summary

CVE-2025-49907 is a Missing Authorization vulnerability in the WordPress plugin "MDTF – wp-meta-data-filter-and-taxonomy-filter" by RealMag777. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized data exposure or manipulation. The vulnerability affects all versions up to and including 1.3.3.9. With a CVSS score of 4.3 (Medium), the risk is moderate but significant due to the lack of required authentication. No public proof-of-concept (PoC) or exploit code is currently available, and the patch status remains unknown.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin ecosystem. Users are advised to monitor the official WordPress plugin repository or the vendor's site for updates. Since no patch is available, consider disabling the plugin or implementing strict access controls as a temporary measure.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Base Score: 4.3 (Medium)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: Low (C:L)
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)

The threat level is medium due to the low complexity and no authentication requirement, but the impact is limited to low confidentiality loss.

Deep Dive & Mechanics

The vulnerability stems from a Missing Authorization check (CWE-862) in the MDTF plugin. The plugin likely exposes REST API endpoints or AJAX actions that perform sensitive operations (e.g., reading or modifying meta data and taxonomy filters) without verifying the user's permissions. An attacker can send crafted HTTP requests to these endpoints to access or manipulate data that should be restricted to authenticated users with specific roles.

The affected component is the plugin's core functionality for handling meta data filters and taxonomy filters. The lack of proper capability checks allows any unauthenticated visitor to trigger these actions.

Vulnerable vs. Patched Code

Since no patch is available, we can only describe the vulnerable pattern. A typical vulnerable code snippet might look like:

// Vulnerable: No capability check
add_action('wp_ajax_nopriv_mdtf_filter', 'mdtf_handle_filter');
function mdtf_handle_filter() {
    // Process filter data without checking user permissions
    $data = $_POST['filter_data'];
    // ... process and return sensitive data
}

A patched version would include a capability check:

// Patched: Added capability check
add_action('wp_ajax_mdtf_filter', 'mdtf_handle_filter');
add_action('wp_ajax_nopriv_mdtf_filter', 'mdtf_handle_filter');
function mdtf_handle_filter() {
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized');
    }
    $data = $_POST['filter_data'];
    // ... process and return sensitive data
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target WordPress site with MDTF plugin version <= 1.3.3.9
• Network access to the site

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=mdtf_filter).
2. Send a crafted POST request without authentication:

   curl -X POST http://target/wp-admin/admin-ajax.php \
        -d 'action=mdtf_filter&filter_data=malicious_payload'
   

3. Observe the response for unauthorized data exposure.

Note: No public exploit code is available; this is a conceptual demonstration.

Blue Team

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with actions related to MDTF (e.g., mdtf_filter, mdtf_save).
• Look for requests from unauthenticated users to these endpoints.
• Check for anomalous data in filter parameters.

Hunting:

• Search logs for action=mdtf_ patterns in POST requests.
• Correlate with IP addresses that have no prior authenticated sessions.

Indicators of Compromise (IOCs)

• Network:
  • POST requests to /wp-admin/admin-ajax.php with action=mdtf_* parameters from unauthenticated sources.
  • Unusual filter_data payloads containing SQL-like or serialized PHP objects.
• File:
  • Modified or unexpected entries in the wp_options table related to MDTF settings.
• Log:
  • Repeated 200 responses to admin-ajax.php without prior login events.

Detection Engineering

YARA Rule

rule CVE_2025_49907_MDTF_Missing_Auth {
    meta:
        description = "Detects exploitation attempts for CVE-2025-49907 in MDTF plugin"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2025-49907"
    strings:
        $ajax_action = /action=mdtf_[a-z_]+/
        $filter_data = /filter_data=/
    condition:
        $ajax_action and $filter_data
}

Sigma Rule

title: CVE-2025-49907 MDTF Missing Authorization Exploitation
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthenticated POST requests to MDTF plugin AJAX actions
author: Valters IT
date: 2025/04/01
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: POST
        cs-uri-query|contains: 'action=mdtf_'
        cs-uri-query|contains: 'admin-ajax.php'
    condition: selection
falsepositives:
    - Legitimate authenticated users (rare)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-49907 MDTF Missing Authorization Attempt"; flow:to_server; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=mdtf_"; http_client_body; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin if not critical for operations.
2. Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with action=mdtf_* from unauthenticated users.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• Apply a patch from the vendor once available.
• Consider forking the plugin and adding proper capability checks (e.g., current_user_can('edit_posts')) to all AJAX handlers.

Workaround:

• Use .htaccess to restrict access to admin-ajax.php:

  <Files "admin-ajax.php">
      Require all denied
  </Files>
  

  (Note: This may break legitimate AJAX functionality; use with caution.)

Valters IT