CVE-2023-51357

Executive Summary

CVE-2023-51357 is a Missing Authorization vulnerability in the Conversios.io WordPress plugin (enhanced-e-commerce-for-woocommerce-store) affecting versions through 6.5.0. This flaw allows unauthenticated attackers to exploit incorrectly configured access control security levels, potentially leading to unauthorized data access or manipulation of WooCommerce analytics settings. The vulnerability has a CVSS score of 5.3 (Medium) and an EPSS score of 0.0%, indicating low exploitation likelihood at this time. However, due to the lack of a vendor patch, affected sites remain at risk.

Supply Chain & Package Security

This vulnerability resides in a WordPress plugin distributed via the official WordPress plugin repository. The plugin is not available on NPM, PyPI, Go, or Ruby ecosystems. The supply chain risk is limited to WordPress site administrators who install the plugin directly from the WordPress dashboard or via manual upload. No known malicious packages have been identified.

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: 5.3 (Medium)
• Attack Vector: Network
• Attack Complexity: Low
• Privileges Required: None
• User Interaction: None
• Scope: Unchanged
• Confidentiality Impact: Low
• Integrity Impact: None
• Availability Impact: None

Threat Level: Medium. The vulnerability is easy to exploit remotely without authentication, but the impact is limited to low confidentiality loss. No public exploit code exists, and EPSS probability is near zero.

Deep Dive & Mechanics

The vulnerability stems from a missing authorization check in the Conversios.io plugin's REST API endpoints or AJAX handlers. The plugin likely registers WordPress REST API routes or admin-ajax actions that should require a specific capability (e.g., manage_options) but fails to verify the user's permissions. This allows any unauthenticated visitor to call these endpoints and potentially:

• Retrieve sensitive WooCommerce analytics data (e.g., order counts, revenue, customer information).
• Modify plugin settings (e.g., Google Analytics tracking IDs, conversion tracking configurations).
• Access internal plugin logs or debug information.

The flaw is classified under CWE-862: Missing Authorization, meaning the software does not perform an authorization check when an actor attempts to access a resource or perform an action.

Vulnerable vs. Patched Code

Since no official patch exists, the vulnerable code remains in all versions <= 6.5.0. A hypothetical patch would involve adding capability checks to all REST API endpoints and AJAX handlers.

Vulnerable Code Example (PHP):

add_action('wp_ajax_nopriv_conversios_get_data', 'conversios_get_data_callback');
function conversios_get_data_callback() {
    // No permission check
    $data = get_option('conversios_analytics_data');
    wp_send_json_success($data);
}

Patched Code Example (PHP):

add_action('wp_ajax_conversios_get_data', 'conversios_get_data_callback');
add_action('wp_ajax_nopriv_conversios_get_data', 'conversios_get_data_callback');
function conversios_get_data_callback() {
    if (!current_user_can('manage_options')) {
        wp_die('Unauthorized', 403);
    }
    $data = get_option('conversios_analytics_data');
    wp_send_json_success($data);
}

Exploitation & Lab Setup

Red Team

Prerequisites:

• Target WordPress site with Conversios.io plugin <= 6.5.0 installed and activated.
• No authentication required.

Exploitation Steps:

1. Identify vulnerable endpoints: Use a web proxy (e.g., Burp Suite) or browser developer tools to monitor AJAX requests made by the plugin. Look for actions like conversios_get_data, conversios_save_settings, etc.

2. Craft a direct request: Send a GET or POST request to the vulnerable endpoint without any authentication cookies.

   Example using curl:

   curl -X POST "https://target.com/wp-admin/admin-ajax.php" \
        -d "action=conversios_get_data"
   

3. Analyze response: If the endpoint returns sensitive data (e.g., JSON with analytics info), the vulnerability is confirmed.

4. Escalate impact: Attempt to modify plugin settings by sending crafted parameters.

   curl -X POST "https://target.com/wp-admin/admin-ajax.php" \
        -d "action=conversios_save_settings&tracking_id=UA-XXXXX-Y"
   

Note: No public exploit code exists; this is a manual exploitation guide.

Blue Team

Detection & Response:

1. Monitor for unusual AJAX requests: Look for requests to /wp-admin/admin-ajax.php with actions containing conversios_ from unauthenticated sources.

2. Check server logs: Search for 200 responses to admin-ajax.php with action=conversios_* from IPs not associated with authenticated admin sessions.

3. Review plugin settings: Verify that Google Analytics tracking IDs and other configurations have not been tampered with.

4. Implement virtual patching: Use a Web Application Firewall (WAF) to block requests to admin-ajax.php with action parameters starting with conversios_ unless the request includes a valid nonce or authentication cookie.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP POST requests to /wp-admin/admin-ajax.php with action=conversios_* parameters from unauthenticated sources.
  • Unusual outbound traffic to unknown analytics endpoints (if attacker modifies tracking IDs).

• File IOCs:

  • Modified plugin files in /wp-content/plugins/enhanced-e-commerce-for-woocommerce-store/.
  • Unexpected entries in WordPress options table (wp_options) with keys like conversios_*.

• Log IOCs:

  • Web server access logs showing repeated POST /wp-admin/admin-ajax.php requests with action=conversios_* from the same IP.
  • WordPress debug log entries indicating failed capability checks (if patched).

Detection Engineering

YARA Rule

rule Detect_Conversios_Missing_Auth {
    meta:
        description = "Detects vulnerable Conversios.io plugin files with missing authorization"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2023-51357"
    strings:
        $ajax_action = /add_action\(['\"]wp_ajax_nopriv_conversios_/
        $rest_route = /register_rest_route\(.*conversios/
    condition:
        any of them
}

Sigma Rule

title: Unauthenticated Access to Conversios.io AJAX Endpoints
id: 8a4b3c2d-1e5f-6a7b-8c9d-0e1f2a3b4c5d
status: experimental
description: Detects unauthenticated requests to Conversios.io plugin AJAX endpoints
author: Valters IT
date: 2025/04/10
logsource:
    category: webserver
    product: apache
    service: access
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'action=conversios_'
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin requests (should include nonce)
level: medium

Suricata Rule

alert http any any -> any any (msg:"CVE-2023-51357 - Unauthenticated Conversios AJAX Access"; flow:to_server; http.method; content:"POST"; http.uri; content:"/wp-admin/admin-ajax.php"; http.client_body; content:"action=conversios_"; nocase; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the plugin until a patch is available. Navigate to WordPress Admin > Plugins and deactivate "Enhanced E-commerce for WooCommerce Store".
2. Implement a WAF rule to block unauthenticated requests to admin-ajax.php with action=conversios_*.
3. Audit site logs for any signs of exploitation.

Long-term Fix:

• Monitor the plugin's official page for updates. If no patch is released, consider migrating to an alternative WooCommerce analytics plugin (e.g., Google Analytics for WooCommerce by WooCommerce).
• Apply the principle of least privilege to all WordPress plugins and regularly review their permissions.

Workaround Code (PHP): Add the following to your theme's 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, 'conversios_') === 0) {
            wp_die('Unauthorized', 403);
        }
    }
});

Valters IT
DevSecOps & Cyber Threat Intelligence