Zyxel USG/USG FLEX/VPN/ATP Error Message os command injection

Summaryinfo

A vulnerability was found in Zyxel USG, USG FLEX, VPN and ATP. It has been declared as critical. Affected by this issue is some unknown functionality of the component Error Message Handler. Executing a manipulation can lead to os command injection. This vulnerability appears as CVE-2023-28771. The attack may be performed from remote. In addition, an exploit is available.

Detailsinfo

A vulnerability was found in Zyxel USG, USG FLEX, VPN and ATP (Network Encryption Software) (version now known). It has been declared as very critical. This vulnerability affects some unknown processing of the component Error Message Handler. The manipulation with an unknown input leads to a os command injection vulnerability. The CWE definition for the vulnerability is CWE-78. The product 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. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was presented 04/25/2023. The advisory is available at zyxel.com. This vulnerability was named CVE-2023-28771 since 03/23/2023. Technical details are unknown but a public exploit is available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 03/13/2025). This vulnerability is assigned to T1202 by the MITRE ATT&CK project.

It is possible to download the exploit at packetstormsecurity.com. It is declared as attacked. This issue was added on 05/31/2023 to the CISA Known Exploited Vulnerabilities Catalog with a due date of 06/21/2023:

Apply updates per vendor instructions.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Network Encryption Software

Vendor

• Zyxel

Name

• ATP
• USG
• USG FLEX
• VPN

License

• commercial

Website

• Vendor: https://www.zyxel.com/

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion