CVE-2022-50683
📋 TL;DR
A stored cross-site scripting vulnerability in Kentico Xperience allows attackers to inject malicious scripts via form redirect URL configuration settings. This enables execution of arbitrary JavaScript in users' browsers when they interact with affected forms. Organizations using vulnerable Kentico Xperience installations are affected.
💻 Affected Systems
- Kentico Xperience
📦 What is this software?
Xperience by Kentico
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal user session cookies, perform actions as authenticated users, redirect to malicious sites, or deploy malware through browser exploitation.
Likely Case
Session hijacking, credential theft, or defacement of application pages through injected malicious scripts.
If Mitigated
Limited to low-privilege actions if proper input validation and output encoding are implemented, though some user interaction would still be required.
🎯 Exploit Status
Exploitation requires ability to modify form configuration settings, typically requiring some level of administrative access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Kentico hotfix downloads for specific version
Vendor Advisory: https://devnet.kentico.com/download/hotfixes
Restart Required: Yes
Instructions:
1. Download the appropriate hotfix from Kentico DevNet. 2. Backup your application. 3. Apply the hotfix according to Kentico's installation instructions. 4. Restart the application server. 5. Verify the fix by testing form redirect functionality.
🔧 Temporary Workarounds
Input Validation for Form Redirect URLs
allImplement server-side validation to ensure form redirect URLs only contain allowed characters and protocols
Output Encoding
allApply proper HTML encoding to all user-controlled data before rendering in browser responses
🧯 If You Can't Patch
- Restrict access to form configuration interfaces to only trusted administrators
- Implement web application firewall rules to detect and block XSS payloads in form submissions
🔍 How to Verify
Check if Vulnerable:
Test if form redirect URL fields accept and execute JavaScript payloads like <script>alert('XSS')</script>Check Version:
Check Kentico administration interface or web.config for version informationVerify Fix Applied:
Attempt to inject XSS payloads into form redirect URL fields and verify they are properly sanitized or rejected📡 Detection & Monitoring
Log Indicators:
- Unusual modifications to form configuration settings
- Administrative actions from unexpected IP addresses or users
Network Indicators:
- HTTP requests containing JavaScript payloads in form parameters
- Unexpected redirects from form submissions
SIEM Query:
source="web_server" AND (uri="*/cmsmodules/forms/*" OR uri="*/admin/*") AND (message="*<script>*" OR message="*javascript:*")