Malware on website with outdated Joomla

See: http://killmalware.com/paardensportdiepenveen.nl/#
See: https://www.virustotal.com/nl/url/6a94843b9bac0c1f821c41d898c111d58cc3d9649f15af64d6605aa2d8c24417/analysis/
Blacklisted: http://quttera.com/detailed_report/paardensportdiepenveen.nl
See: https://sitecheck.sucuri.net/results/paardensportdiepenveen.nl
Web application version:
Joomla Version 3.4.1 found at: htxp://www.paardensportdiepenveen.nl/lr-pc_v2//administrator/manifests/files/joomla.xml
No modules were found passively in HTML source & No plugins were found passively in HTML source

Included linked JS scripts:
Javascript
/lr-pc_v2/media/jui/js/jquery.min.js
/lr-pc_v2/media/jui/js/jquery-noconflict.js
/lr-pc_v2/media/jui/js/jquery-migrate.min.js *
/lr-pc_v2/media/system/js/caption.js
/lr-pc_v2/media/jui/js/bootstrap.min.js
/lr-pc_v2/templates/protostar/js/template.js

Also malware flagged here: http://urlquery.net/report.php?id=1430758935627 (Fortinet’s Webfilter alerts)

polonus (volunteer website security analyst and website error-hunter)