CVE-2025-22318

Executive Summary

CVE-2025-22318 is a Missing Authorization vulnerability (CWE-862) in the Standard Box Sizes – for WooCommerce WordPress plugin by enituretechnology. This flaw affects all versions up to and including 1.6.13. The vulnerability allows an unauthenticated attacker to trigger unauthorized actions within the plugin, potentially leading to data manipulation or denial of service. The CVSS score is 7.5 (High), driven by network attack vector, low complexity, and no privileges required. As of this report, no official patch has been released, and no public exploit code is available. The plugin is part of the WordPress ecosystem, and exploitation could impact WooCommerce store operations.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. Users are advised to monitor the plugin’s update channel for a patched version. Since no patch is available, the supply chain risk is elevated—users must consider disabling the plugin or applying virtual patching via a Web Application Firewall (WAF).

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
• Base Score: 7.5 (High)
• Attack Vector: Network (AV:N) – exploitable remotely.
• Attack Complexity: Low (AC:L) – no special conditions required.
• Privileges Required: None (PR:N) – unauthenticated.
• User Interaction: None (UI:N) – no victim action needed.
• Scope: Unchanged (S:U) – vulnerability does not affect other components.
• Confidentiality Impact: None (C:N) – no data exposure.
• Integrity Impact: Low (I:L) – limited data modification possible.
• Availability Impact: High (A:H) – could cause service disruption.

Threat Level: High. The combination of no authentication requirement and potential for availability impact makes this a serious risk for WooCommerce stores.

Deep Dive & Mechanics

The vulnerability stems from missing authorization checks in the plugin’s AJAX handlers or REST endpoints. The plugin likely registers actions that are intended for administrative users but fails to verify the user’s capabilities before execution. An unauthenticated attacker can send crafted HTTP requests to these endpoints, triggering functions that modify plugin settings, clear cache, or perform other operations that should be restricted.

Root Cause: The plugin does not call current_user_can() or wp_verify_nonce() on critical AJAX actions, allowing any visitor to invoke them.

Attack Vector: HTTP POST/GET requests to WordPress admin-ajax.php or REST API endpoints with specific action parameters.

Impact: An attacker could:

• Disable or modify box size configurations, causing shipping calculations to fail.
• Delete stored data, leading to denial of service.
• Potentially inject malicious settings if the plugin writes to the database without sanitization.

Vulnerable vs. Patched Code

Since no patch is available, we can only infer the vulnerable pattern. The plugin likely has code similar to:

Vulnerable Code (PHP):

add_action('wp_ajax_nopriv_update_box_size', 'update_box_size_callback');
function update_box_size_callback() {
    // Missing capability check
    update_option('box_size_data', $_POST['data']);
    wp_die();
}

Patched Code (Hypothetical):

add_action('wp_ajax_nopriv_update_box_size', 'update_box_size_callback');
function update_box_size_callback() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    check_ajax_referer('box_size_nonce', 'nonce');
    update_option('box_size_data', sanitize_text_field($_POST['data']));
    wp_die();
}

The patch would add capability checks and nonce verification to all AJAX handlers.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Target WordPress site with Standard Box Sizes plugin <= 1.6.13.
• No authentication required.

Exploitation Steps:

1. Identify the vulnerable AJAX action (e.g., standard_box_sizes_update).
2. Send a crafted POST request to wp-admin/admin-ajax.php:

curl -X POST http://target/wp-admin/admin-ajax.php \
  -d "action=standard_box_sizes_update&data=malicious_payload"

3. The server processes the request without authorization, potentially modifying plugin settings.

Proof-of-Concept (No public exploit available):

import requests

target = "http://target/wp-admin/admin-ajax.php"
payload = {"action": "standard_box_sizes_update", "data": "attacker_controlled"}
response = requests.post(target, data=payload)
print(response.status_code)

Blue Team (Detection & Hardening)

Detection:

• Monitor for unexpected POST requests to admin-ajax.php with action parameters related to "standard_box_sizes".
• Alert on 200 responses from unauthenticated users to these endpoints.

Hardening:

• Disable the plugin until a patch is released.
• Use a WAF to block requests to admin-ajax.php with unknown actions from unauthenticated users.
• Implement virtual patching by adding a custom function to functions.php:

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

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP requests to /wp-admin/admin-ajax.php with action=standard_box_sizes_* parameters from unauthenticated IPs.
  • Unusual POST data containing data parameter with unexpected values.

• File IOCs:

  • Modified options in wp_options table with keys like box_size_data or standard_box_sizes_settings.
  • Plugin files in /wp-content/plugins/standard-box-sizes/ with unexpected modifications.

• Log IOCs:

  • Web server logs showing 200 responses to admin-ajax.php from unauthenticated users.
  • PHP error logs with warnings about undefined array keys (if attacker sends malformed data).

Detection Engineering

YARA Rule

rule CVE_2025_22318_WordPress_Plugin {
    meta:
        description = "Detects vulnerable Standard Box Sizes plugin files"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-22318"
    strings:
        $vuln_func = "wp_ajax_nopriv_" nocase
        $action = "standard_box_sizes" nocase
        $missing_check = "current_user_can" nocase
    condition:
        $vuln_func and $action and not $missing_check
}

Sigma Rule

title: CVE-2025-22318 - Missing Authorization in Standard Box Sizes Plugin
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects unauthenticated AJAX requests to vulnerable plugin endpoints
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'admin-ajax.php'
        cs-uri-query|contains: 'action=standard_box_sizes'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin actions (if logged in)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-22318 - Missing Authorization in Standard Box Sizes"; flow:to_server,established; content:"POST"; http_method; content:"admin-ajax.php"; http_uri; content:"action=standard_box_sizes"; http_client_body; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patched version is released.
2. Apply virtual patching via WAF rules blocking unauthenticated requests to admin-ajax.php with action=standard_box_sizes*.
3. Monitor logs for exploitation attempts.

Long-term Fix:

• The vendor must release a patched version (e.g., 1.6.14) that adds capability checks and nonce verification to all AJAX handlers.
• Users should update to the latest version once available.

Workaround:

• Add the following code to the theme’s functions.php to block unauthenticated access:

add_action('wp_ajax_nopriv_*', function() {
    $action = $_REQUEST['action'] ?? '';
    if (strpos($action, 'standard_box_sizes') !== false) {
        wp_die('Unauthorized', 403);
    }
}, 1);

Valters IT – DevSecOps & Cyber Threat Intelligence