CVE-2024-10580

Executive Summary

CVE-2024-10580 is a Missing Authorization vulnerability in the Hustle – Email Marketing, Lead Generation, Optins, Popups plugin for WordPress, affecting all versions up to and including 7.8.5. The core issue lies in the submit_form() function, which lacks a capability check, allowing unauthenticated attackers to submit unpublished forms. This can lead to unauthorized data injection, spam submissions, and potential data integrity issues within the WordPress ecosystem.

This vulnerability is classified as a WordPress plugin security issue and does not involve Apache or Nginx directly. The CVSS score of 5.3 (Medium) reflects the low impact on confidentiality and availability, but the ease of exploitation (no authentication required) makes it a practical target for automated attacks.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Users are advised to monitor for updates from the vendor (Hustle) and apply patches as soon as they become available. No known supply chain compromise has been reported.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
• Base Score: 5.3 (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: None (C:N)
• Integrity Impact: Low (I:L)
• Availability Impact: None (A:N)

The threat level is Medium due to the low integrity impact and lack of authentication required. However, the vulnerability can be exploited to submit arbitrary data to unpublished forms, potentially leading to spam, data pollution, or further attacks if the form data is processed unsafely.

Deep Dive & Mechanics

The vulnerability resides in the submit_form() function within the Hustle plugin. This function handles form submissions from the frontend. In vulnerable versions, the function does not verify whether the user has the necessary capabilities (e.g., wp_verify_nonce or current_user_can) before processing the submission. As a result, any unauthenticated user can submit data to forms that are in a "draft" or "unpublished" state.

The attack flow:

1. An attacker identifies a WordPress site running Hustle <= 7.8.5.
2. The attacker sends a POST request to the form submission endpoint (typically /wp-admin/admin-ajax.php with action hustle_submit_form).
3. The request includes the form ID and any required fields.
4. The submit_form() function processes the request without checking if the form is published or if the user is authorized.
5. The form data is saved to the database, potentially triggering email notifications or other actions.

This can be used to:

• Submit spam or malicious content to unpublished forms.
• Trigger email alerts to site administrators with crafted payloads.
• Pollute the database with unwanted entries.

Vulnerable vs. Patched Code

Vulnerable Code (<= 7.8.5):

public function submit_form() {
    // No capability check
    $form_id = $_POST['form_id'];
    $data = $_POST['data'];
    // Process submission...
}

Patched Code (Hypothetical):

public function submit_form() {
    // Check if user can submit forms
    if ( ! current_user_can( 'submit_hustle_form' ) ) {
        wp_die( 'Unauthorized', 403 );
    }
    // Verify nonce
    if ( ! wp_verify_nonce( $_POST['_wpnonce'], 'hustle_submit_form' ) ) {
        wp_die( 'Nonce verification failed', 403 );
    }
    $form_id = intval( $_POST['form_id'] );
    // Check if form is published
    $form = Hustle_Module_Model::instance()->get( $form_id );
    if ( 'publish' !== $form->status ) {
        wp_die( 'Form is not active', 403 );
    }
    $data = $_POST['data'];
    // Process submission...
}

The patch adds:

• A capability check (current_user_can).
• Nonce verification.
• A check to ensure the form is published before processing.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A WordPress site with Hustle plugin <= 7.8.5.
• Knowledge of a valid form ID (can be enumerated or guessed).

Exploit Steps:

1. Identify the form submission endpoint: POST /wp-admin/admin-ajax.php
2. Craft a request with the required parameters:
   • action: hustle_submit_form
   • form_id: <target_form_id>
   • data: JSON-encoded form fields (e.g., {"email":"attacker@example.com","name":"Test"})
3. Send the request using curl or a script.

Example curl command:

curl -X POST https://target-site.com/wp-admin/admin-ajax.php \
  -d "action=hustle_submit_form&form_id=123&data=%7B%22email%22%3A%22attacker%40example.com%22%7D"

Expected Result: The form submission is accepted even if the form is unpublished.

Blue Team (Detection & Response)

Detection Steps:

1. Monitor for POST requests to /wp-admin/admin-ajax.php with action=hustle_submit_form from unauthenticated users.
2. Check for form submissions to forms with post_status other than publish.
3. Review server logs for unusual submission patterns (e.g., high volume from a single IP).

Response:

• Immediately update the Hustle plugin to the latest version if a patch is available.
• If no patch exists, disable the plugin or implement a web application firewall (WAF) rule to block unauthenticated submissions.
• Investigate any suspicious form data for malicious content.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /wp-admin/admin-ajax.php with action=hustle_submit_form from unauthenticated IPs.
  • Unusual form submission data (e.g., script tags, SQL injection attempts).
• Host IOCs:
  • Database entries in wp_hustle_entries or similar tables with form_id pointing to unpublished forms.
  • Log entries showing hustle_submit_form action without a valid nonce or capability.
• File IOCs:
  • Modified or unexpected files in /wp-content/plugins/hustle/ (if attacker uploads malicious code).

Detection Engineering

YARA Rule

rule detect_cve_2024_10580_hustle_submit {
    meta:
        description = "Detects exploitation attempts of CVE-2024-10580 in Hustle plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2024-10580"
    strings:
        $action = "hustle_submit_form"
        $ajax = "admin-ajax.php"
        $form_id = "form_id"
    condition:
        all of them
}

Sigma Rule

title: CVE-2024-10580 Hustle Unauthorized Form Submission
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthenticated POST requests to Hustle form submission endpoint
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: POST
        cs-uri-query|contains: "admin-ajax.php"
        cs-uri-query|contains: "action=hustle_submit_form"
    condition: selection
falsepositives:
    - Legitimate form submissions from authenticated users (if nonce is present)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-10580 Hustle Unauthorized Form Submission"; flow:to_server; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=hustle_submit_form"; http_client_body; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Update the plugin: If a patched version is released, update Hustle to the latest version immediately.
2. Disable the plugin: If no patch is available, deactivate and delete the Hustle plugin until a fix is released.
3. Implement WAF rules: Block POST requests to /wp-admin/admin-ajax.php with action=hustle_submit_form from unauthenticated users.

Long-term Measures:

• Enforce capability checks and nonce verification in all custom WordPress plugins.
• Regularly audit plugin code for missing authorization checks.
• Monitor the WordPress plugin repository for security updates.

Workaround:

• Add a custom function to your theme's functions.php to check for user capabilities before processing form submissions:

add_action( 'wp_ajax_hustle_submit_form', 'custom_hustle_submit_check', 1 );
add_action( 'wp_ajax_nopriv_hustle_submit_form', 'custom_hustle_submit_check', 1 );
function custom_hustle_submit_check() {
    if ( ! is_user_logged_in() ) {
        wp_die( 'Unauthorized', 403 );
    }
}

Valters IT
Securing Digital Frontiers