vb.org Archive - Suggestion to block a possible hack?

Last night my server/vbull was hacked I believe.

The following files had redirects in them to forum/install/install.php.

===
/forum/readme.txt
/forum/includes/init.php
/forum/includes/class_core.php
/forum/includes/class_core.php.bak
/forum/admincpsecure/diagnostic.php
/forum/admincpsecure/global.php
/forum/class_core.bkU
/forum/vb4_readme.html
/forum/vb4_readme.txt
/forum/forum.php

I do not have a /install directory as it was deleted/removed some time ago. However, a hidden directory was suddenly there last night - it did not have any files in it though so all the redirects were going to the non-existent install.php file which resulted in a 404 - file not found - error.

This was a real mess and I ended up restoring a full backup. After that all was fine and the hidden /install directory was no longer present.

I am running V4.1.12 patch 4 and wondering if this is a known issue and it there is a patch. I password protected the /install directory using .htaccess.

X vBulletin 3.8.12 by vBS Debug Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
Messages:

X vBulletin 3.8.12 by vBS Debug Information

Page Generation 0.00948 seconds
Memory Usage 1,699KB
Queries Executed 10 (?)

More Information

Template Usage:

(1)ad_footer_end
(1)ad_footer_start
(1)ad_header_end
(1)ad_header_logo
(1)ad_navbar_below
(1)footer
(1)gobutton
(1)header
(1)headinclude
(6)option
(1)post_thanks_navbar_search
(1)printthread
(1)printthreadbit
(1)spacer_close
(1)spacer_open

Phrase Groups Available:

global
postbit
showthread

Included Files:

./printthread.php
./global.php
./includes/init.php
./includes/class_core.php
./includes/config.php
./includes/functions.php
./includes/class_hook.php
./includes/modsystem_functions.php
./includes/class_bbcode_alt.php
./includes/class_bbcode.php
./includes/functions_bigthree.php

Hooks Called:

init_startup
init_startup_session_setup_start
init_startup_session_setup_complete
cache_permissions
fetch_threadinfo_query
fetch_threadinfo
fetch_foruminfo
style_fetch
cache_templates
global_start
parse_templates
global_setup_complete
printthread_start
bbcode_fetch_tags
bbcode_create
bbcode_parse_start
bbcode_parse_complete_precache
bbcode_parse_complete
printthread_post
printthread_complete

Messages:

X vBulletin 3.8.12 by vBS Debug Information
Page Generation 0.00948 seconds Memory Usage 1,699KB Queries Executed 10 (?)
More Information
Template Usage: (1)ad_footer_end (1)ad_footer_start (1)ad_header_end (1)ad_header_logo (1)ad_navbar_below (1)footer (1)gobutton (1)header (1)headinclude (6)option (1)post_thanks_navbar_search (1)printthread (1)printthreadbit (1)spacer_close (1)spacer_open Phrase Groups Available: global postbit showthread	Included Files: ./printthread.php ./global.php ./includes/init.php ./includes/class_core.php ./includes/config.php ./includes/functions.php ./includes/class_hook.php ./includes/modsystem_functions.php ./includes/class_bbcode_alt.php ./includes/class_bbcode.php ./includes/functions_bigthree.php Hooks Called: init_startup init_startup_session_setup_start init_startup_session_setup_complete cache_permissions fetch_threadinfo_query fetch_threadinfo fetch_foruminfo style_fetch cache_templates global_start parse_templates global_setup_complete printthread_start bbcode_fetch_tags bbcode_create bbcode_parse_start bbcode_parse_complete_precache bbcode_parse_complete printthread_post printthread_complete
Messages: