register_options([
      OptString.new('ATRUNPATH', [true, 'Location of atrun binary', '/usr/libexec/atrun']),
      OptString.new('MAILDIR', [true, 'Location of mailboxes', '/var/mail']),
      OptString.new('WritableDir', [ true, 'A directory where we can write files', '/tmp' ]),
      OptInt.new('ListenerTimeout', [true, 'Number of seconds to wait for the exploit', 603])