CVE-2023-28767 : Vulnerability Insights and Analysis

This CVE-2023-28767 involves a vulnerability in Zyxel products' firmware that could be exploited by an unauthenticated LAN-based attacker to inject operating system commands into the device configuration data when cloud management mode is enabled.

Understanding CVE-2023-28767

This section delves into the specifics of the CVE-2023-28767 vulnerability, its impact, technical details, and mitigation strategies.

What is CVE-2023-28767?

The CVE-2023-28767 vulnerability arises from the failure of the configuration parser to sanitize user-controlled input in various Zyxel firmware versions. Specifically, the affected versions include Zyxel ATP series firmware 5.10 through 5.36, USG FLEX series firmware 5.00 through 5.36, USG FLEX 50(W) series firmware 5.10 through 5.36, USG20(W)-VPN series firmware 5.10 through 5.36, and VPN series firmware 5.00 through 5.36.

The Impact of CVE-2023-28767

With a CVSSv3.1 base score of 8.8 and a high-severity rating, this vulnerability poses a significant threat. An attacker could exploit it to execute malicious OS commands on affected devices when the cloud management mode is active. The potential impacts include high confidentiality, integrity, and availability concerns.

Technical Details of CVE-2023-28767

Here, we delve into the vulnerability description, affected systems and versions, as well as the exploitation mechanism.

Vulnerability Description

The vulnerability stems from the inadequate sanitization of user-controlled input in Zyxel firmware versions, enabling an attacker to inject OS commands into device configuration data.

Affected Systems and Versions

The impacted Zyxel products include ATP series firmware (versions 5.10 through 5.36), USG FLEX series firmware (versions 5.00 through 5.36), USG FLEX 50(W) series firmware (versions 5.10 through 5.36), USG20(W)-VPN series firmware (versions 5.10 through 5.36), and VPN series firmware (versions 5.00 through 5.36).

Exploitation Mechanism

An unauthenticated LAN-based attacker can leverage this vulnerability specifically when the cloud management mode is enabled to inject harmful OS commands into the device configuration data.

Mitigation and Prevention

In light of CVE-2023-28767, proactive measures must be taken to mitigate risks and enhance security posture.

Immediate Steps to Take

Ensure that devices are not operating in cloud management mode unless necessary.
Monitor network traffic for any suspicious activities.
Implement firewall rules to restrict unauthorized access.

Long-Term Security Practices

Regularly update firmware to patched versions.
Conduct security assessments and penetration testing.
Educate users on best security practices and potential threats.

Patching and Updates

Zyxel has released updates to address this vulnerability. It is crucial for users to apply the latest firmware patches promptly to protect their systems from exploitation.