Totolink A7100RU Command Injection Vulnerability in CGI Handler

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

Impact

Exploitation of this vulnerability allows for arbitrary command execution on the affected device with root privileges. This could lead to a complete compromise of the router and possibly the network it is connected to.

Reproduction

To reproduce this vulnerability, send a POST request to '/cgi-bin/cstecgi.cgi' with the 'topicurl' parameter set to 'setVpnAccountCfg' and the 'user' parameter containing the command to be executed, such as a 'wget' command. The router will execute the injected command, demonstrating the command injection vulnerability.