Totolink A8000RU Command Injection Vulnerability in CGI Handler

A command injection vulnerability has been identified in the Totolink A8000RU router, specifically in the version 7.1cu.643_b20200521. The issue resides within the CGI handler, in a function called setRadvdCfg, located in the file /cgi-bin/cstecgi.cgi. This vulnerability allows remote attackers to execute arbitrary operating system commands by manipulating the maxRtrAdvInterval parameter. 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 router with root privileges, leading to a full compromise of the device. This could also result in further exploitation of the connected network.

Reproduction

To reproduce this vulnerability, send a POST request to the /cgi-bin/cstecgi.cgi endpoint with the maxRtrAdvInterval parameter set to a crafted command, such as 'ls>./setRadvdCfg.txt'. The router will execute the command and create a text file containing the command output.