CVE-2024-50417

Executive Summary

CVE-2024-50417 is a Missing Authorization vulnerability in the Bold Page Builder WordPress plugin by Bold-Themes, affecting versions up to and including 5.1.3. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized data modification or privilege escalation within the WordPress ecosystem. The vulnerability has a CVSS score of 4.3 (Medium) and an EPSS score of 0.0%, indicating low exploitation likelihood at this time. No public proof-of-concept or patch details are currently available.

WordPress Ecosystem Context

This vulnerability specifically targets the Bold Page Builder plugin, a component of the WordPress content management system. The issue lies in the plugin’s failure to properly enforce authorization checks on certain AJAX actions or REST API endpoints, allowing unauthenticated users to trigger administrative functions.

CVSS Breakdown & Threat Level

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

Threat Level: Medium. While the CVSS score is moderate, the lack of authentication requirements and potential for privilege escalation in a WordPress environment elevates the risk for unpatched sites.

Deep Dive & Mechanics

The vulnerability stems from missing authorization checks in the Bold Page Builder plugin’s AJAX handlers or REST API endpoints. Specifically, the plugin fails to validate user capabilities (e.g., edit_posts, manage_options) before executing sensitive operations such as saving page templates, modifying plugin settings, or triggering database writes. An unauthenticated attacker can craft HTTP requests to these endpoints, bypassing WordPress’s built-in nonce and capability checks.

Root Cause: The plugin uses wp_ajax_* hooks without corresponding wp_ajax_nopriv_* checks, or implements custom REST routes without permission_callback validation. This allows any visitor to invoke administrative functions.

Attack Vector: The attacker sends a crafted POST request to /wp-admin/admin-ajax.php with action parameters that trigger unauthorized operations. For example:

POST /wp-admin/admin-ajax.php HTTP/1.1
Host: target-site.com
Content-Type: application/x-www-form-urlencoded

action=bold_page_builder_save_template&template_data=...

Vulnerable vs. Patched Code

Since no official patch is available, the following illustrates the vulnerable pattern and a hypothetical fix.

Vulnerable Code (PHP):

add_action('wp_ajax_bold_page_builder_save_template', 'bold_save_template');
function bold_save_template() {
    // No capability check
    $template_data = $_POST['template_data'];
    update_option('bold_template', $template_data);
    wp_die();
}

Patched Code (Hypothetical):

add_action('wp_ajax_bold_page_builder_save_template', 'bold_save_template');
function bold_save_template() {
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized', 403);
    }
    check_ajax_referer('bold_nonce', 'nonce');
    $template_data = sanitize_text_field($_POST['template_data']);
    update_option('bold_template', $template_data);
    wp_die();
}

Exploitation & Lab Setup

Red Team (Attacker)

1. Setup: Deploy a WordPress instance with Bold Page Builder <= 5.1.3.
2. Recon: Identify vulnerable endpoints by analyzing plugin source code or using fuzzing tools.
3. Exploit: Send unauthenticated POST requests to admin-ajax.php with action parameters like bold_page_builder_save_settings.
4. Payload Example:

curl -X POST http://target/wp-admin/admin-ajax.php \
  -d "action=bold_page_builder_save_settings&setting=admin_email&value=attacker@evil.com"

5. Impact: Modify plugin settings, inject malicious content, or escalate privileges.

Blue Team (Defender)

1. Detection: Monitor for unusual admin-ajax.php requests from unauthenticated users.
2. Honeypot: Create a fake endpoint to log attacker behavior.
3. Mitigation: Implement a Web Application Firewall (WAF) rule to block requests to admin-ajax.php with suspicious action parameters.
4. Forensics: Check WordPress logs for unauthorized option changes.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /wp-admin/admin-ajax.php with action parameters containing bold_page_builder_*.
  • Unusual User-Agent strings or repeated requests from the same IP.
• File IOCs:
  • Modified wp_options table entries with bold_ prefix.
  • Unexpected files in /wp-content/uploads/bold-page-builder/.
• Log IOCs:
  • WordPress debug log entries showing wp_ajax_bold_page_builder_* calls without authentication.

Detection Engineering

YARA Rule

rule CVE_2024_50417_Bold_Page_Builder {
    meta:
        description = "Detects exploitation attempts for CVE-2024-50417 in Bold Page Builder"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-50417"
    strings:
        $ajax_action = /action=bold_page_builder_[a-z_]+/
        $admin_ajax = /\/wp-admin\/admin-ajax\.php/
    condition:
        $admin_ajax and $ajax_action
}

Sigma Rule

title: CVE-2024-50417 - Bold Page Builder Unauthenticated AJAX Access
id: 8a3f7c2e-9b1d-4f5a-8c6e-2d3f1a0b9c8d
status: experimental
description: Detects unauthenticated POST requests to admin-ajax.php with Bold Page Builder actions
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: POST
        cs-uri-query|contains: admin-ajax.php
        cs-uri-query|re: action=bold_page_builder_
    condition: selection
falsepositives:
    - Legitimate admin actions (requires authentication)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-50417 - Bold Page Builder Unauthenticated AJAX Access"; flow:to_server; http.method; content:"POST"; http.uri; content:"/wp-admin/admin-ajax.php"; http.client_body; content:"action=bold_page_builder_"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Actions:

   • Disable the Bold Page Builder plugin until a patch is available.
   • Implement a WAF rule to block requests to admin-ajax.php with bold_page_builder_ action parameters.
   • Restrict access to /wp-admin/ via IP whitelisting or .htaccess.

2. Long-term Fix:

   • Apply vendor patch when released (monitor Bold-Themes updates).
   • Conduct a security audit of all WordPress plugins for similar authorization flaws.
   • Enforce principle of least privilege for all plugin capabilities.

3. Detection:

   • Deploy the provided YARA, Sigma, and Suricata rules.
   • Enable WordPress audit logging to track plugin-related AJAX calls.

Valters IT
Securing Digital Frontiers