UTT HiPER 840G Buffer Overflow Vulnerability in API Endpoint Allowing Remote Exploitation

A critical buffer overflow vulnerability has been identified in the UTT HiPER 840G router, affecting firmware versions through 3.1.1-190328. The vulnerability resides in the API endpoint '/goform/formP2PLimitConfig', specifically within the function 'sub_484E40'. An attacker can manipulate the 'except' parameter, leading to a stack-based buffer overflow. This vulnerability can be exploited remotely, causing a denial-of-service condition.

Impact

Exploitation of this vulnerability leads to a stack-based buffer overflow, causing a denial-of-service condition on the device.

Reproduction

The vulnerability can be reproduced by sending a POST request to the '/goform/formP2PLimitConfig' endpoint. The request must include a carefully crafted 'except' parameter that exceeds the buffer's capacity, causing a buffer overflow. This can be done by using a long string of characters in the 'except' parameter, which the server-side application does not properly validate before processing.