Totolink A7100RU Command Injection Vulnerability in CGI Handler

A command injection vulnerability has been identified in the Totolink A7100RU router, specifically in the firmware version 7.4cu.2313_b20191024. The issue arises within the CGI handler, in a function called 'UploadOpenVpnCert', located in the file '/cgi-bin/cstecgi.cgi'. This vulnerability allows remote attackers to execute arbitrary operating system commands by manipulating the 'FileName' parameter in a crafted request. The injected commands are executed with root privileges, potentially leading to a full compromise of the router and its connected network.

Impact

Exploitation of this vulnerability allows for arbitrary OS command execution with root privileges on the affected router.

Reproduction

To reproduce this vulnerability, send a POST request to '/cgi-bin/cstecgi.cgi' with the 'FileName' parameter set to a command, such as 'wget', to demonstrate the command execution. The router will execute the injected command, such as downloading a file from a specified URL.