Tenda AX-3 Stack Overflow Vulnerability Leading to Denial-of-Service

A stack overflow vulnerability has been identified in the Tenda AX-3 router, specifically in version 16.03.12.10_CN. The issue arises in the 'fromAdvSetMacMtuWan' function, where the 'serviceName2' parameter is processed. The vulnerability allows attackers to cause a denial-of-service condition by sending a crafted request that exploits the lack of bounds checking in the 'strcpy' function. This oversight enables the overflow of a fixed-size buffer in the WAN_ARGUMENT structure, corrupting adjacent stack memory and potentially overwriting critical variables and control data, leading to a crash.

Impact

Exploitation of this vulnerability causes the router to crash, disrupting its ability to provide services and causing a persistent denial-of-service condition.

Reproduction

The vulnerability can be reproduced by sending a POST request to the '/goform/AdvSetMacMtuWan' endpoint with a 'serviceName2' parameter that is excessively long, such as 7000 characters. This can be done using a script that automates the request, such as one written in Python using the 'requests' library.