CVE-2022-50682
📋 TL;DR
A CRLF injection vulnerability in Kentico Xperience's routing engine allows attackers to manipulate URL query string redirects through improper encoding. This enables header injection attacks that could facilitate cross-site scripting, session hijacking, or other web application attacks. Organizations using vulnerable Kentico Xperience versions are affected.
💻 Affected Systems
- Kentico Xperience
📦 What is this software?
Xperience by Kentico
⚠️ Risk & Real-World Impact
Worst Case
Attackers could inject malicious HTTP headers to perform session hijacking, redirect users to phishing sites, execute cross-site scripting attacks, or facilitate other web application compromises.
Likely Case
Attackers would typically use this to inject headers for session fixation, cross-site scripting, or redirect users to malicious sites via manipulated redirects.
If Mitigated
With proper input validation and output encoding, the vulnerability would be prevented, though the underlying code flaw would still exist.
🎯 Exploit Status
CRLF injection vulnerabilities are typically straightforward to exploit once the attack vector is identified
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Hotfix available through Kentico devnet (specific version not provided)
Vendor Advisory: https://devnet.kentico.com/download/hotfixes
Restart Required: Yes
Instructions:
1. Download the hotfix from Kentico devnet. 2. Apply the hotfix to your Kentico Xperience installation. 3. Restart the application/web server. 4. Test that URL redirects properly encode CRLF characters.
🔧 Temporary Workarounds
Input Validation Filter
allImplement custom input validation to detect and block CRLF sequences in URL parameters
Implement custom HTTP module or middleware to sanitize URL parameters before routing
Web Application Firewall Rule
allConfigure WAF to block requests containing CRLF sequences in URL parameters
Add WAF rule to detect and block %0D%0A, %0D, %0A, \r\n sequences in query strings
🧯 If You Can't Patch
- Implement strict input validation on all URL parameters to reject CRLF sequences
- Configure reverse proxy or WAF to sanitize URL parameters before reaching the application
🔍 How to Verify
Check if Vulnerable:
Test by accessing a page with URL parameters containing CRLF sequences (e.g., ?param=test%0D%0AInjected-Header:value) and checking if headers are injectedCheck Version:
Check Kentico Xperience version through admin interface or by examining assembly versionsVerify Fix Applied:
After patching, repeat the vulnerability test and verify that CRLF sequences are properly encoded or rejected📡 Detection & Monitoring
Log Indicators:
- HTTP requests with URL parameters containing %0D%0A, %0D, %0A sequences
- Unusual redirect patterns or header modifications in logs
Network Indicators:
- HTTP requests with CRLF sequences in query strings
- Responses with injected headers from redirects
SIEM Query:
source="web_server" AND (url="*%0D%0A*" OR url="*%0D*" OR url="*%0A*")