feel free to keep it strictly simple...
check folder
Modul check_folder_secure
Author Wolfgang Studer
Type admin tool
Version 1.03.000
State Stable
License GPL
GUID 76aa2205-3000-4e14-ba07-6ca0068dd1f2
Platform LEPTON 1.x/2.x hybrid
Last info 2015-11-17
Forum http://forum.lepton-cms.org/viewtopic.php?f=61&t=2724
Download check_folder_secure-V1.03.000.zip
Description This module shows folders with missing INDEX File
Info This module looks over all folders of your lepton installation and searches for folders missed an index.php

Then you can either create one by one or all at once.
Image check_folder_secure.png