CVE-2024-0536: Critical Remote Buffer Overflow Vulnerability in Tenda W9 1.0.0.7(4456)

Overview

A critical vulnerability has been detected in the Tenda W9 1.0.0.7(4456), a popular router model used by individuals and organizations worldwide. This vulnerability, identified as CVE-2024-0536, specifically targets the setWrlAccessList function within the httpd component of the device. The critical nature of this vulnerability lies in the potential for remote exploitation, which could lead to a complete system compromise or data leakage.

This vulnerability is of particular concern due to the ability of potential attackers to exploit it remotely, without any form of user interaction. The impact of a successful exploit is severe, with the potential for unauthorized system control or data leakage. Immediate attention and mitigation measures are strongly advised.

Vulnerability Summary

CVE ID: CVE-2024-0536
Severity: Critical 8.8 (CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage

Affected Products

Product | Affected Versions
——–|——————-
Tenda W9 | 1.0.0.7(4456)

How the Exploit Works

The vulnerability lies within the setWrlAccessList function of the httpd component in Tenda W9. It arises due to improper handling of the argument ssidIndex, leading to a stack-based buffer overflow. A malicious actor can manipulate this argument to overflow the buffer, potentially gaining the ability to execute arbitrary code and take control of the system.

Conceptual Example Code

Here’s a conceptual example of how the vulnerability might be exploited, using a malicious HTTP request:

POST /setWrlAccessList HTTP/1.1
Host: target.tenda.router
Content-Type: application/x-www-form-urlencoded

ssidIndex=AAAAAAAAAAAAAAA... [long string to overflow]

In this example, the `ssidIndex` parameter is filled with a long string designed to overflow the buffer. This could potentially allow an attacker to execute arbitrary code or cause a denial of service.

Mitigation Guidance

Users of Tenda W9 running the affected version are highly advised to apply the vendor patch as soon as it becomes available. In the meantime, employing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation measure. Also, restrict network access to the device as much as possible until the patch is applied, to minimize the risk of remote exploitation.