Tenda AC21 Stack-Based Buffer Overflow Vulnerability in SetSysTimeCfg Remote Command Execution

A stack-based buffer overflow vulnerability has been identified in the Tenda AC21 router, specifically in the 16.03.08.16 firmware version. The issue arises within the '/goform/SetSysTimeCfg' endpoint of the '/bin/httpd' binary, where the 'timeZone' and 'time' parameters can be manipulated, leading to a buffer overflow. This vulnerability can be exploited remotely, causing a denial-of-service condition and potentially allowing for remote command execution.

Impact

Exploitation of this vulnerability causes a denial-of-service condition and could lead to unauthorized remote command execution on the affected device.

Reproduction

The vulnerability can be reproduced by sending a POST request to '/goform/SetSysTimeCfg' with an overly long 'timeZone' or 'time' parameter. The 'timeType' parameter must be set to 'manual' to trigger the vulnerability. This can be done using a web browser or a tool like curl or Postman.