CVE-2020-9054 : Exploit Details and Defense Strategies

Multiple ZyXEL network-attached storage (NAS) devices running firmware version 5.21 are vulnerable to pre-authentication command injection in weblogin.cgi.

Understanding CVE-2020-9054

This CVE involves a critical vulnerability in ZyXEL NAS devices that could allow remote attackers to execute arbitrary code on the affected devices.

What is CVE-2020-9054?

The vulnerability arises from a pre-authentication command injection flaw in ZyXEL NAS devices running firmware version 5.21. Attackers can exploit this issue to execute malicious commands on the device remotely.

The Impact of CVE-2020-9054

Remote, unauthenticated attackers can potentially execute arbitrary code on vulnerable ZyXEL devices with root privileges.
Exploitation can lead to complete compromise of the device, allowing attackers to take control remotely.

Technical Details of CVE-2020-9054

ZyXEL NAS devices running firmware version 5.21 are affected by a critical pre-authentication command injection vulnerability.

Vulnerability Description

The flaw allows remote attackers to inject and execute arbitrary commands on the device via the weblogin.cgi CGI executable.

Affected Systems and Versions

Affected products include NAS326, NAS520, NAS540, NAS542, and several end-of-support models.

Exploitation Mechanism

Attackers can exploit the vulnerability by sending specially-crafted HTTP POST or GET requests to the device, potentially leading to remote code execution.

Mitigation and Prevention

ZyXEL has provided firmware updates to address the CVE-2020-9054 vulnerability.

Immediate Steps to Take

Apply the latest firmware updates provided by ZyXEL for the affected NAS devices.
Block access to the ZyXEL device web interface to mitigate the risk of exploitation.

Long-Term Security Practices

Regularly update firmware and security patches on all network devices.
Implement network segmentation and access controls to restrict unauthorized access.

Patching and Updates

ZyXEL has released firmware updates for NAS326, NAS520, NAS540, NAS542, and other affected devices to address the vulnerability.