CVE-2025-47556

Executive Summary

CVE-2025-47556 is a Missing Authorization vulnerability in the QuanticaLabs CSS3 Compare Pricing Tables WordPress plugin, affecting versions up to and including 11.6. This flaw allows an unauthenticated attacker to exploit incorrectly configured access control security levels, potentially leading to unauthorized data exposure or modification of pricing table configurations. As a WordPress plugin vulnerability, it directly impacts the WordPress ecosystem, not the underlying web server software. The vulnerability has a CVSS score of 5.4 (Medium), with no known public proof-of-concept or exploit code currently available. The patch status remains unknown, placing affected sites at elevated risk.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository and third-party marketplaces. Organizations using this plugin should treat it as a supply chain risk, as the plugin's update mechanism may not automatically patch the flaw. Manual verification of plugin versions and vendor communication is essential.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
• Base Score: 5.4 (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 user action required.
• Scope: Unchanged (S:U) – Impact confined to the vulnerable component.
• Confidentiality Impact: Low (C:L) – Limited unauthorized data access.
• Integrity Impact: Low (I:L) – Limited unauthorized modification.
• Availability Impact: None (A:N) – No denial-of-service risk.

Threat Level: Medium. While the CVSS score is moderate, the lack of a patch and the plugin's widespread use in pricing table implementations elevate the real-world risk for unpatched sites.

Deep Dive & Mechanics

The vulnerability stems from missing authorization checks in the plugin's AJAX handlers or REST API endpoints. The plugin css3_web_pricing_tables_grids likely exposes functions to create, read, update, or delete pricing table data without verifying the user's capabilities (e.g., edit_posts or manage_options). An unauthenticated attacker can send crafted HTTP requests to these endpoints, bypassing WordPress's built-in capability checks.

Root Cause: The plugin fails to call current_user_can() or similar authorization functions before processing sensitive actions. This allows any visitor to manipulate pricing table data, potentially injecting malicious content or extracting configuration details.

Attack Flow:

1. Attacker identifies the vulnerable endpoint (e.g., /wp-admin/admin-ajax.php?action=css3_pricing_update).
2. Sends a POST request with parameters to modify or retrieve pricing table data.
3. The plugin processes the request without checking user permissions.
4. Attacker achieves unauthorized data access or modification.

Vulnerable vs. Patched Code

Since no patch is available, the following illustrates the vulnerable pattern and a hypothetical fix.

Vulnerable Code (PHP):

add_action('wp_ajax_nopriv_css3_pricing_update', 'css3_pricing_update_handler');
function css3_pricing_update_handler() {
    // Missing authorization check
    $table_id = $_POST['table_id'];
    update_option('css3_pricing_table_' . $table_id, $_POST['data']);
    wp_send_json_success();
}

Patched Code (Hypothetical):

add_action('wp_ajax_css3_pricing_update', 'css3_pricing_update_handler');
function css3_pricing_update_handler() {
    // Added authorization check
    if (!current_user_can('edit_posts')) {
        wp_die('Unauthorized', 403);
    }
    $table_id = $_POST['table_id'];
    update_option('css3_pricing_table_' . $table_id, $_POST['data']);
    wp_send_json_success();
}

Key Differences:

• The vulnerable handler uses wp_ajax_nopriv_* (accessible to unauthenticated users) and lacks capability checks.
• The patched version uses wp_ajax_* (authenticated users only) and adds current_user_can() verification.

Exploitation & Lab Setup

Red Team (Attacker) Perspective

Prerequisites:

• Target WordPress site with CSS3 Compare Pricing Tables plugin <= 11.6.
• Network access to the site.

Exploitation Steps:

1. Enumerate Endpoints: Identify AJAX actions by scanning the plugin's JavaScript files or using a tool like Burp Suite.
2. Craft Request: Send a POST request to /wp-admin/admin-ajax.php with the vulnerable action.
3. Extract Data: Retrieve pricing table configurations containing sensitive information.

Example cURL Command:

curl -X POST https://target.com/wp-admin/admin-ajax.php \
  -d "action=css3_pricing_get&table_id=1" \
  -H "Content-Type: application/x-www-form-urlencoded"

Expected Output: JSON response containing pricing table data (e.g., plan names, prices, features).

Blue Team (Defender) Perspective

Detection & Response:

1. Monitor AJAX Requests: Log all requests to /wp-admin/admin-ajax.php with suspicious actions.
2. Check Plugin Version: Use wp plugin get css3-web-pricing-tables-grids to verify version.
3. Harden Permissions: Ensure WordPress user roles are properly configured.
4. Web Application Firewall (WAF): Block requests to unknown AJAX actions.

Lab Setup:

• Install WordPress 6.x with the vulnerable plugin.
• Use a local environment (e.g., XAMPP, Docker) for testing.
• Monitor logs with tail -f /var/log/apache2/access.log.

Indicators of Compromise (IOCs)

• Network IOCs:
  • POST requests to /wp-admin/admin-ajax.php with action=css3_pricing_* parameters.
  • Unusual JSON responses containing pricing table data from unauthenticated sources.
• File IOCs:
  • Modified wp_options entries with keys like css3_pricing_table_*.
  • Unexpected files in /wp-content/uploads/ related to pricing tables.
• Log IOCs:
  • Repeated 200 responses to /wp-admin/admin-ajax.php from unknown IPs.
  • Absence of current_user_can calls in plugin logs.

Detection Engineering

YARA Rule

rule CVE_2025_47556_WordPress_Plugin {
    meta:
        description = "Detects vulnerable CSS3 Compare Pricing Tables plugin files"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-47556"
    strings:
        $vuln_func = "wp_ajax_nopriv_css3_pricing" nocase
        $missing_auth = "current_user_can" nocase
    condition:
        $vuln_func and not $missing_auth
}

Sigma Rule

title: CVE-2025-47556 - Missing Authorization in CSS3 Compare Pricing Tables
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects exploitation attempts against missing authorization vulnerability
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        c-uri: '/wp-admin/admin-ajax.php'
        cs-uri-query:
            - '*action=css3_pricing_*'
    condition: selection
falsepositives:
    - Legitimate admin actions (rare)
level: high

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2025-47556 - Missing Authorization in CSS3 Compare Pricing Tables";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/wp-admin/admin-ajax.php"; http_uri;
    content:"action=css3_pricing_"; http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
    reference:cve,2025-47556;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the Plugin: Deactivate and remove css3-web-pricing-tables-grids until a patch is available.
2. Web Application Firewall (WAF): Block requests containing action=css3_pricing_ in POST bodies.
3. Access Control: Restrict /wp-admin/admin-ajax.php to authenticated users via .htaccess:

   <Files "admin-ajax.php">
       Require valid-user
   </Files>
   

Long-Term Fix:

• Monitor the plugin vendor's website for a patched version (>= 11.7).
• Implement a WordPress security plugin (e.g., Wordfence) to detect unauthorized AJAX requests.
• Conduct regular vulnerability scans using tools like WPScan.

Workaround:

• If the plugin is critical, manually add authorization checks by editing the plugin's PHP files (not recommended for production).

Valters IT
Securing Digital Frontiers