TOTOLINK A702R Buffer Overflow Vulnerability in Form Filter Function

A buffer overflow vulnerability has been identified in the TOTOLINK A702R router, specifically in firmware version 4.0.0-B20211108.1423. The issue arises in the 'sub_4162DC' function within the '/boafrm/formFilter' endpoint. This vulnerability can be exploited remotely, leading to a crash of the affected program.

Impact

Exploitation of this vulnerability causes a buffer overflow, which can typically lead to arbitrary code execution or a denial-of-service condition, causing the device to crash.

Reproduction

The vulnerability can be reproduced by sending a POST request to the '/boafrm/formFilter' endpoint. The request must include a 'sessionCheck' parameter and an 'ip6addr' parameter that is excessively long, exceeding the buffer capacity. This can be done using a web browser or a tool like curl, by specifying the appropriate headers and content type.