CVE-2023-34138 in ATP
Summary
by MITRE • 07/17/2023
A command injection vulnerability in the hotspot management feature of the Zyxel ATP series firmware versions 4.60 through 5.36 Patch 2, USG FLEX series firmware versions 4.60 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 4.60 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 4.60 through 5.36 Patch 2, and VPN series firmware versions 4.60 through 5.36 Patch 2. could allow an unauthenticated, LAN-based attacker to execute some OS commands on an affected device if the attacker could trick an authorized administrator to add their IP address to the list of trusted RADIUS clients in advance.
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Analysis
by VulDB Data Team • 07/18/2023
The vulnerability identified as CVE-2023-34138 represents a critical command injection flaw within the hotspot management functionality of several Zyxel network security appliances. This issue affects multiple product lines including the ATP series, USG FLEX series, USG FLEX 50(W) series, USG20(W)-VPN series, and VPN series devices. The vulnerability exists in firmware versions ranging from 4.60 through 5.36 Patch 2, creating a widespread impact across Zyxel's network security portfolio. The flaw specifically resides in how the system handles RADIUS client configuration, where improper input validation allows malicious command execution. This vulnerability operates under the Common Weakness Enumeration framework as CWE-77, which categorizes command injection vulnerabilities that occur when user-supplied data is directly incorporated into system commands without proper sanitization or validation.
The technical exploitation of this vulnerability requires a specific attack vector involving social engineering or pre-authorization by an administrator. An unauthenticated attacker positioned on the local network must first trick an authorized administrator into adding the attacker's IP address to the list of trusted RADIUS clients. Once this prerequisite is met, the attacker can leverage the command injection flaw to execute arbitrary operating system commands on the affected device. This type of attack follows the ATT&CK framework's technique T1059.001 for command and scripting interpreter, where adversaries manipulate system processes through injected commands. The vulnerability demonstrates a dangerous privilege escalation path since it allows attackers to execute commands with the privileges of the affected device's operating system, potentially leading to full system compromise.
The operational impact of this vulnerability extends beyond simple command execution, as it provides attackers with persistent access to network infrastructure that could be used for further reconnaissance and lateral movement within the network. An attacker who successfully exploits this vulnerability could potentially modify network configurations, intercept traffic, or establish backdoors for continued access. The affected devices typically serve as critical network security components, making this vulnerability particularly dangerous as it could allow attackers to bypass network security controls and potentially compromise the entire network infrastructure. The vulnerability's requirement for administrator interaction creates a unique risk profile where social engineering becomes a critical attack factor, making it particularly challenging to defend against through traditional network security measures.
Mitigation strategies for CVE-2023-34138 should focus on immediate firmware updates from Zyxel, which would contain patches addressing the command injection vulnerability. Organizations should also implement network segmentation to limit local network access to administrative functions, particularly for devices running vulnerable firmware versions. Additional defensive measures include monitoring for unusual RADIUS client additions and implementing strict access controls for administrative functions. Network administrators should disable unnecessary hotspot management features and ensure that only trusted IP addresses are added to RADIUS client lists. The vulnerability's classification under CWE-77 and its exploitation pattern align with ATT&CK technique T1059.001, emphasizing the need for proper input validation and command sanitization. Regular security audits should verify that no unauthorized RADIUS client entries exist, and that administrative access controls remain properly configured to prevent unauthorized modifications to critical network components.