CVE-2024-50500

Executive Summary

CVE-2024-50500 is a Missing Authorization vulnerability in the Averta Shortcodes and Extra Features for Phlox Theme (auxin-elements) plugin for WordPress. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized access to certain plugin functionalities. The vulnerability affects all versions up to and including 2.17.4. With a CVSS score of 4.3 (Medium), the risk is moderate but significant due to the lack of authentication required for exploitation. No public proof-of-concept (PoC) or exploit code has been released at this time, and the patch status remains unknown.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. As a WordPress ecosystem component, it is not subject to NPM, PyPI, Go, or Ruby package management. However, the risk extends to any site using the Phlox theme with the auxin-elements plugin, potentially affecting thousands of WordPress installations. Supply chain security is a concern as the plugin is a common dependency for Phlox theme users, and the lack of a patch increases the attack surface.

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) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No user action required.
• Scope: Unchanged (S:U) – Vulnerability affects only the vulnerable component.
• Confidentiality Impact: Low (C:L) – Limited information disclosure possible.
• Integrity Impact: None (I:N) – No data modification.
• Availability Impact: None (A:N) – No denial of service.

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the impact is limited to low confidentiality loss. However, in the context of WordPress, this could expose sensitive configuration data or allow further chaining with other vulnerabilities.

Deep Dive & Mechanics

The vulnerability stems from a Missing Authorization check (CWE-862) in the auxin-elements plugin. The plugin provides shortcodes and extra features for the Phlox theme, and certain AJAX actions or REST endpoints are not properly protected with capability checks. An unauthenticated attacker can send crafted HTTP requests to these endpoints to access functionality that should require administrative privileges.

The flaw likely exists in the plugin’s AJAX handlers or REST API routes that are registered without verifying user permissions. For example, endpoints used for retrieving theme options, shortcode previews, or other internal data may be exposed. The attacker can enumerate these endpoints and extract information such as plugin configurations, nonces, or other sensitive data that could aid in further attacks.

The vulnerability is classified as Exploiting Incorrectly Configured Access Control Security Levels, meaning the plugin fails to enforce proper role-based access control (RBAC). This is a common issue in WordPress plugins where developers assume that certain actions are only accessible via the admin dashboard, but they forget to add current_user_can() checks.

Vulnerable vs. Patched Code

Since no official patch is available, the following is a hypothetical comparison based on the vulnerability type.

Vulnerable Code (hypothetical):

add_action('wp_ajax_nopriv_auxin_get_data', 'auxin_get_data_callback');
function auxin_get_data_callback() {
    // No permission check
    $data = get_option('auxin_theme_options');
    wp_send_json($data);
}

Patched Code (hypothetical):

add_action('wp_ajax_auxin_get_data', 'auxin_get_data_callback');
function auxin_get_data_callback() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized');
    }
    $data = get_option('auxin_theme_options');
    wp_send_json($data);
}

The patched version adds a capability check (current_user_can('manage_options')) and removes the nopriv hook to prevent unauthenticated access.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Target WordPress site with auxin-elements plugin <= 2.17.4 and Phlox theme.
• No authentication required.

Exploitation Steps:

1. Identify vulnerable endpoints by analyzing the plugin’s JavaScript or source code for AJAX actions without nopriv checks.
2. Send a crafted HTTP request to the vulnerable endpoint, e.g.:

   curl -X POST 'http://target/wp-admin/admin-ajax.php' \
   -d 'action=auxin_get_data&nonce=123456'
   

3. If the endpoint returns sensitive data (e.g., theme options, API keys), the exploitation is successful.

No public exploit code is available. The above is a generic example.

Blue Team (Detection & Defense)

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with actions related to auxin-elements (e.g., auxin_*).
• Look for requests from unauthenticated users to endpoints that should require admin privileges.
• Use the Sigma rule below to detect exploitation attempts.

Defense:

• Immediately disable the auxin-elements plugin if no patch is available.
• Implement a Web Application Firewall (WAF) rule to block requests to known vulnerable endpoints.
• Restrict access to admin-ajax.php for unauthenticated users using .htaccess or server-level rules.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /wp-admin/admin-ajax.php with action parameter containing auxin_ prefix.
  • Unusual response data containing theme options or plugin configuration.
• File IOCs:
  • Modified or suspicious files in /wp-content/plugins/auxin-elements/.
  • Unexpected log entries in WordPress debug log.
• Behavioral IOCs:
  • Unauthorized access to admin-only features without authentication.
  • Sudden changes to theme settings or shortcode behavior.

Detection Engineering

YARA Rule

rule CVE_2024_50500_Auxin_Elements_Missing_Auth {
    meta:
        description = "Detects exploitation attempts for CVE-2024-50500 in auxin-elements plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-50500"
    strings:
        $ajax_action = /action=auxin_[a-z_]+/
        $admin_ajax = "admin-ajax.php"
        $nopriv = "nopriv"
    condition:
        $admin_ajax and $ajax_action and not $nopriv
}

Sigma Rule

title: CVE-2024-50500 Auxin Elements Missing Authorization
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthenticated AJAX requests to auxin-elements plugin endpoints
author: Valters IT
date: 2025/04/10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2024-50500
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: POST
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=auxin_'
    condition: selection
falsepositives:
    - Legitimate admin users accessing the plugin
level: medium
tags:
    - attack.initial_access
    - attack.t1190

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-50500 Auxin Elements Missing Authorization Attempt"; flow:to_server,established; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=auxin_"; http_client_body; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the auxin-elements plugin until a patch is released.
2. Monitor logs for exploitation attempts using the provided detection rules.
3. Implement a WAF rule to block requests to admin-ajax.php with action parameters starting with auxin_ from unauthenticated users.

Long-term Fix:

• The vendor must release a patched version that adds proper capability checks to all AJAX and REST endpoints.
• Users should update to the latest version once available.
• Consider using a security plugin like Wordfence to add virtual patching.

Workaround:

• Add the following to .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
Senior DevSecOps & Cyber Threat Intelligence Expert