Tenda G3 Stack Overflow Vulnerability in formModifyPppAuthWhiteMac Function Allowing Denial-of-Service

A stack overflow vulnerability has been identified in the Tenda G3 router, specifically in version 3.0br_V15.11.0.17. The issue arises in the formModifyPppAuthWhiteMac function, where the pppoeServerWhiteMacIndex parameter is processed without proper length validation. This oversight allows remote attackers to send crafted requests that overflow the stack-based buffer, leading to a denial-of-service condition or potentially allowing remote code execution.

Impact

Exploitation of this vulnerability causes a denial-of-service condition, with the potential for remote code execution.

Reproduction

The vulnerability can be reproduced by sending an HTTP POST request to the '/goform/PppAuthWhiteMacModify' endpoint. The request must include a 'pppoeServerWhiteMacIndex' parameter with a value that exceeds the buffer length, such as a string of repeated characters.