Tenda CH22 Buffer Overflow Vulnerability in frmL7ImForm Function

A buffer overflow vulnerability has been identified in the Tenda CH22 router, specifically in version 1.0.0.1. The issue arises in the frmL7ImForm function within the /goform/L7Im file. The vulnerability allows remote attackers to manipulate the 'page' argument, leading to a buffer overflow condition. This exploitation can cause the router to become unresponsive or 'paralyzed'.

Impact

Exploitation of this vulnerability causes a buffer overflow, which can lead to arbitrary code execution or causing the device to become unresponsive. In this case, the router is destroyed and made inaccessible.

Reproduction

The vulnerability can be reproduced by sending a POST request to the /goform/L7Im endpoint with a crafted 'page' parameter that exceeds the buffer size, causing a buffer overflow. This can be done using a script that automates the process, such as one written in Python that uses the requests library to send the payload.