CVE-2025-31415

Executive Summary

CVE-2025-31415 is a Missing Authorization vulnerability in the YayExtra WordPress plugin (by YayCommerce) affecting versions up to and including 1.5.2. The flaw allows unauthenticated attackers to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access, modification, or privilege escalation. The vulnerability is classified as High Severity (CVSS 7.6) and currently has no known public exploit or patch. Given the WordPress ecosystem, this plugin is widely used for WooCommerce extra features, making it a high-value target for automated scanning and exploitation.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. Organizations using YayExtra should immediately audit their plugin version and restrict network access to the plugin’s REST endpoints until a patch is released. The lack of a patch increases supply chain risk, as compromised sites can be used for lateral movement or data exfiltration.

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) – Exploit does not affect other components.
• Confidentiality (C): High (H) – Full data exposure possible.
• Integrity (I): Low (L) – Limited data modification.
• Availability (A): Low (L) – Minor service disruption possible.

Threat Level: High – Unauthenticated remote exploitation with low complexity.

Deep Dive & Mechanics

The vulnerability stems from missing authorization checks in the YayExtra plugin’s AJAX handlers or REST API endpoints. The plugin likely fails to verify user capabilities (e.g., manage_options, edit_posts) before executing sensitive operations such as:

• Retrieving order or customer data.
• Modifying plugin settings.
• Triggering administrative actions.

Attackers can craft HTTP requests to these unprotected endpoints, bypassing WordPress’s built-in nonce and capability checks. The flaw is classified under CWE-862: Missing Authorization, meaning the software does not perform any authorization check when an actor attempts to access a resource or perform an action.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is inferred from similar WordPress plugin vulnerabilities:

Vulnerable (yayextra <= 1.5.2):

add_action('wp_ajax_nopriv_yayextra_get_data', 'yayextra_get_data');
function yayextra_get_data() {
    // No capability check
    $data = get_option('yayextra_sensitive_data');
    wp_send_json_success($data);
}

Patched (hypothetical):

add_action('wp_ajax_nopriv_yayextra_get_data', 'yayextra_get_data');
function yayextra_get_data() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    $data = get_option('yayextra_sensitive_data');
    wp_send_json_success($data);
}

The patched version adds current_user_can('manage_options') to restrict access to administrators only.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Target WordPress site with YayExtra <= 1.5.2 active.
• No authentication required.

Exploitation Steps:

1. Identify vulnerable endpoints (e.g., /wp-admin/admin-ajax.php?action=yayextra_get_data).
2. Send a crafted POST/GET request without any nonce or capability token.
3. Parse the JSON response for sensitive data.

Proof-of-Concept (cURL):

curl -X POST "https://target.com/wp-admin/admin-ajax.php" \
  -d "action=yayextra_get_data" \
  -H "Content-Type: application/x-www-form-urlencoded"

Expected Output:

{"success":true,"data":{"orders":["..."]}}

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual AJAX requests to admin-ajax.php with action parameters starting with yayextra_ from unauthenticated users.
• Alert on HTTP 200 responses containing sensitive data (e.g., order details, API keys) from these endpoints.

Hardening:

• Disable the plugin until a patch is released.
• Use a Web Application Firewall (WAF) to block requests to yayextra_* actions from non-admin IPs.
• Implement virtual patching via .htaccess:

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_URI} ^/wp-admin/admin-ajax\.php
RewriteCond %{QUERY_STRING} action=yayextra_ [NC]
RewriteRule .* - [F,L]
</IfModule>

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP requests to /wp-admin/admin-ajax.php with action=yayextra_* parameters.
• Unusual POST data containing yayextra strings from unauthenticated sources.

File IOCs:

• Plugin file: /wp-content/plugins/yayextra/ (version <= 1.5.2).
• Suspicious log entries in WordPress debug log (wp-content/debug.log) showing unauthorized access attempts.

Behavioral IOCs:

• Sudden increase in 403 errors followed by 200 responses from the same IP.
• Unauthorized changes to WooCommerce settings or order statuses.

Detection Engineering

YARA Rule

rule CVE_2025_31415_YayExtra_Missing_Auth {
    meta:
        description = "Detects YayExtra plugin files with missing authorization vulnerability"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-31415"
    strings:
        $vuln_func = "wp_ajax_nopriv_yayextra" nocase
        $no_cap = "current_user_can" nocase
    condition:
        $vuln_func and not $no_cap
}

Sigma Rule

title: CVE-2025-31415 YayExtra Missing Authorization Exploitation
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthenticated AJAX requests to YayExtra plugin endpoints
author: Valters IT
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=yayextra_'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin actions (rare)
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2025-31415 YayExtra Missing Authorization Exploit";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=yayextra_"; http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
    reference:cve,2025-31415;
)

Remediation & Mitigation

Immediate Actions:

1. Disable YayExtra plugin until an official patch is released.
2. Implement WAF rules to block unauthenticated requests to yayextra_* actions.
3. Audit logs for any signs of exploitation (unusual AJAX calls, data exfiltration).

Long-term Fix:

• Apply the vendor patch once available (monitor YayCommerce changelog).
• Upgrade to the latest version of YayExtra (>= 1.5.3 when released).
• Enforce principle of least privilege for all WordPress plugins.

Workaround:

• Add custom code to functions.php to block unauthenticated access:

add_action('init', function() {
    if (defined('DOING_AJAX') && DOING_AJAX && !is_user_logged_in()) {
        $action = $_REQUEST['action'] ?? '';
        if (strpos($action, 'yayextra_') === 0) {
            wp_die('Unauthorized', 403);
        }
    }
});

Valters IT – DevSecOps & Cyber Threat Intelligence