CVE-2025-66064

Executive Summary

CVE-2025-66064 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the Giveaways and Contests by RafflePress WordPress plugin, developed by Syed Balkhi. This vulnerability affects all versions up to and including 1.12.20. The flaw allows an attacker to perform unauthorized actions on behalf of an authenticated administrator, such as modifying giveaway settings, creating new contests, or altering existing ones, without the victim's consent. The vulnerability is classified under CWE-352 and carries a CVSS v3.1 base score of 4.3 (Medium severity). As of the latest analysis, no official patch has been released, and no public proof-of-concept (PoC) or exploit code is available. The EPSS score is 0.0%, indicating a low probability of exploitation in the wild at this time.

WordPress Ecosystem Context

This vulnerability is specific to the WordPress plugin ecosystem. The RafflePress plugin is widely used for managing giveaways and contests on WordPress sites. The CSRF flaw can be exploited to perform state-changing operations, such as updating plugin settings or triggering giveaway actions, without proper nonce validation. This is a classic WordPress plugin security issue, not related to the underlying web server (Apache or Nginx).

CVSS Breakdown & Threat Level

• CVSS Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
• Base Score: 4.3 (Medium)
• 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 malicious link or visit a crafted 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 modification of data or settings.
• Availability Impact (A): None (N) – No denial of service.

Threat Level: Medium. The requirement for user interaction reduces the immediate risk, but the lack of a patch and the potential for social engineering attacks make this a concern for site administrators.

Deep Dive & Mechanics

The CSRF vulnerability in RafflePress arises from the absence of a nonce (number used once) validation on critical administrative actions. In WordPress, nonces are used to verify that requests originate from the legitimate user and not from a third-party site. Without this check, an attacker can craft a malicious HTML page or email that, when visited by an authenticated administrator, triggers a forged request to the RafflePress plugin's admin-ajax.php or admin-post.php endpoints.

Attack Flow:

1. The attacker identifies a state-changing endpoint in RafflePress (e.g., admin-ajax.php?action=rafflepress_save_settings).
2. The attacker crafts a malicious HTML page containing a form or an image tag that automatically submits a POST request to this endpoint.
3. The attacker lures an authenticated RafflePress administrator to visit the malicious page (e.g., via phishing email or a compromised site).
4. The victim's browser sends the forged request, including their session cookies, to the WordPress admin.
5. The server processes the request without verifying the nonce, executing the attacker's desired action (e.g., changing giveaway parameters, deleting contests, or injecting malicious settings).

Root Cause: The plugin's AJAX handlers and admin pages lack nonce verification. This is a common oversight in WordPress plugin development, where developers rely on user authentication but forget to implement CSRF tokens.

Vulnerable vs. Patched Code

Since no official patch is available, the following is a hypothetical comparison based on standard WordPress CSRF remediation.

Vulnerable Code (Example from RafflePress <= 1.12.20):

add_action('wp_ajax_rafflepress_save_settings', 'rafflepress_save_settings_callback');
function rafflepress_save_settings_callback() {
    // No nonce check
    $settings = $_POST['settings'];
    update_option('rafflepress_settings', $settings);
    wp_die();
}

Patched Code (Hypothetical):

add_action('wp_ajax_rafflepress_save_settings', 'rafflepress_save_settings_callback');
function rafflepress_save_settings_callback() {
    // Verify nonce
    if (!isset($_POST['_wpnonce']) || !wp_verify_nonce($_POST['_wpnonce'], 'rafflepress_save_settings')) {
        wp_die('CSRF validation failed.');
    }
    $settings = $_POST['settings'];
    update_option('rafflepress_settings', $settings);
    wp_die();
}

Key Difference: The patched version includes wp_verify_nonce() to validate the request's origin. The nonce should be generated in the admin form using wp_nonce_field() and passed with the AJAX request.

Exploitation & Lab Setup

Red Team (Attacker)

Lab Environment:

• WordPress 6.x with RafflePress 1.12.20 installed and activated.
• Attacker machine with a web server (e.g., Apache) to host the malicious page.
• Victim machine with a browser logged in as an administrator.

Exploitation Steps:

1. Identify a vulnerable endpoint. For example, the plugin may have an AJAX action like rafflepress_reset_giveaway.
2. Create a malicious HTML file (exploit.html):

<html>
<body>
<form action="http://target-site/wp-admin/admin-ajax.php" method="POST" id="csrf-form">
    <input type="hidden" name="action" value="rafflepress_reset_giveaway">
    <input type="hidden" name="giveaway_id" value="1">
    <input type="submit" value="Click me">
</form>
<script>
    document.getElementById('csrf-form').submit();
</script>
</body>
</html>

3. Host the file on the attacker's server and send the link to the victim (e.g., via email).
4. When the victim visits the page, the form auto-submits, executing the CSRF attack.

Note: Since no public exploit code is available, this is a generic example. The exact endpoint and parameters must be discovered through reverse engineering of the plugin's source code.

Blue Team (Defender)

Detection & Prevention:

• Monitor for unusual AJAX requests to admin-ajax.php with actions related to RafflePress (e.g., rafflepress_*).
• Implement Web Application Firewall (WAF) rules to block requests missing a valid nonce parameter.
• Educate administrators about phishing attacks and the importance of not clicking suspicious links while logged in.
• Use WordPress security plugins (e.g., Wordfence) that can add CSRF protection to custom AJAX endpoints.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP POST requests to /wp-admin/admin-ajax.php with action parameter starting with rafflepress_ and no _wpnonce parameter.
  • Referer headers from external domains (e.g., attacker-controlled sites) in admin AJAX requests.
• File IOCs:
  • Modified wp_options table entries for rafflepress_settings or similar options.
  • Unexpected giveaway configurations or contest data in the database.
• Log IOCs:
  • WordPress debug log entries showing failed nonce checks (if patched) or missing nonce warnings.
  • Web server access logs with POST requests to admin-ajax.php from unusual IPs or user agents.

Detection Engineering

YARA Rule

rule CVE_2025_66064_CSRF_RafflePress {
    meta:
        description = "Detects CSRF exploitation attempts against RafflePress plugin"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-66064"
    strings:
        $ajax_action = /action=rafflepress_[a-z_]+/
        $missing_nonce = /(?!.*_wpnonce).*action=rafflepress_/
    condition:
        $ajax_action and #missing_nonce > 0
}

Sigma Rule

title: CSRF Exploitation Against RafflePress Plugin
id: 9a8b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects HTTP requests to WordPress admin-ajax.php with RafflePress actions missing nonce
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        c-uri|contains: '/wp-admin/admin-ajax.php'
        cs-uri-query|contains: 'action=rafflepress_'
    filter:
        cs-uri-query|contains: '_wpnonce='
    condition: selection and not filter
falsepositives:
    - Legitimate plugin updates with nonce (unlikely)
level: medium

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-66064 CSRF RafflePress Exploit"; flow:to_server,established; content:"POST"; http_method; content:"/wp-admin/admin-ajax.php"; http_uri; content:"action=rafflepress_"; http_client_body; pcre:"/^(?!.*_wpnonce).*action=rafflepress_/"; classtype:web-application-attack; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until an official patch is released. This is the most effective mitigation.
2. Implement a Web Application Firewall (WAF) rule to block AJAX requests to RafflePress endpoints that lack a nonce parameter.
3. Restrict admin access to trusted IPs only, reducing the attack surface.

Long-Term Fix:

• The vendor (RafflePress) must release a patched version (e.g., 1.12.21) that adds nonce verification to all AJAX handlers and admin pages. The fix should use wp_nonce_field() and check_ajax_referer() or wp_verify_nonce().
• Users should update to the latest version once available.

Workaround:

• Add custom code to the theme's functions.php to enforce nonce checks for RafflePress actions:

add_action('wp_ajax_rafflepress_save_settings', 'custom_rafflepress_nonce_check', 1);
function custom_rafflepress_nonce_check() {
    if (!isset($_REQUEST['_wpnonce']) || !wp_verify_nonce($_REQUEST['_wpnonce'], 'rafflepress_save_settings')) {
        wp_die('CSRF detected.');
    }
}

Note: This requires knowing the exact nonce action names used by the plugin.

Valters IT
Securing Digital Frontiers