CVE-2023-28771
Published on April 25, 2023

Improper error message handling in Zyxel ZyWALL/USG series firmware versions 4.60 through 4.73, VPN series firmware versions 4.60 through 5.35, USG FLEX series firmware versions 4.60 through 5.35, and ATP series firmware versions 4.60 through 5.35, which could allow an unauthenticated attacker to execute some OS commands remotely by sending crafted packets to an affected device.

Vendor Advisory NVD

Known Exploited Vulnerability

This Zyxel Multiple Firewalls OS Command Injection Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. Zyxel ATP, USG FLEX, VPN, and ZyWALL/USG firewalls allow for improper error message handling which could allow an unauthenticated attacker to execute OS commands remotely by sending crafted packets to an affected device.

The following remediation steps are recommended / required by June 21, 2023: Apply updates per vendor instructions.

Vulnerability Analysis

CVE-2023-28771 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. It has the highest possible exploitability rating (3.9). The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.

What is a Shell injection Vulnerability?

The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

CVE-2023-28771 has been classified to as a Shell injection vulnerability or weakness.

Products Associated with CVE-2023-28771

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What versions are vulnerable to CVE-2023-28771?