Install fail2ban:
sudo apt update && sudo apt install fail2ban -y
Create the Nextcloud-filter:
sudo nano /etc/fail2ban/filter.d/nextcloud.conf
Paste the following lines, this will cover GUI Failed login and WebDAV:
[Definition]
failregex=^.*Login failed: '?.*'? \(Remote IP: '?<HOST>'?\).*$
ignoreregex =
If you want to protect also from direct IP access or wrong Domain name access configure it as below (as per https://github.com/nextcloud/vm/blob/master/apps/fail2ban.sh)
[Definition]
failregex=^.*Login failed: '?.*'? \(Remote IP: '?<HOST>'?\).*$
^.*\"remoteAddr\":\"<HOST>\".*Trusted domain error.*\$
ignoreregex =
Create a new jail:
sudo nano /etc/fail2ban/jail.d/nextcloud.local
Paste the following rows:
[nextcloud]
backend = auto
enabled = true
port = 80,443
protocol = tcp
filter = nextcloud
#Number of retrys before to ban
maxretry = 3
#time in seconds
bantime = 36000
findtime = 36000
#Log path, on Ubuntu usually following
logpath = /var/www/nextcloud/data/nextcloud.log
#For Univention Appliances the logfile is in /var/lib/univention-appcenter/apps/nextcloud/data/nextcloud-data/nextcloud.log
#logpath = /var/lib/univention-appcenter/apps/nextcloud/data/nextcloud-data/nextcloud.log
Re-start the fail2ban-service:
sudo service fail2ban restart
and enjoy your Nextcloud-Server!
P.S. Pattern For GUI:
#Nextcloud 17+
{"reqId":"BRHKHyh1lVFon5D33u4K","level":2,"time":"2020-01-13T12:34:00+00:00","remoteAddr":"10.11.12.13","user":"--","app":"no app in context","method":"POST","url":"\/index.php\/login","message":"Login failed: Tralololjlkl (Remote IP: 10.11.12.13)","userAgent":"Mozilla\/5.0 (Windows NT 10.0; Win64; x64; rv:72.0) Gecko\/20100101 Firefox\/72.0","version":"17.0.2.1"}
#Nextcloud <= 16
{"reqId":"bFnTdevf7ZdCMQ5ddmNl","level":2,"time":"2019-04-03T21:49:30+00:00","remoteAddr":"10.11.12.13","user":"--","app":"core","method":"POST","url":"\/index.php\/login","message":"Login failed: 'Tralololjlkl' (Remote IP: '10.11.12.13')","userAgent":"Mozilla\/5.0 (X11; Ubuntu; Linux x86_64; rv:66.0) Gecko\/20100101 Firefox\/66.0","version":"15.0.5.3"}
For WebDav:
#Nextcloud 17+
{"reqId":"lqdbtb7y3pZSv8sGM0mD","level":2,"time":"2020-01-26T22:20:32+00:00","remoteAddr":"10.11.12.13","user":"--","app":"core","method":"PUT","url":"\/remote.php\/webdav\/files","message":"Login failed: 'webdavlogin' (Remote IP: '10.11.12.13')","userAgent":"curl\/7.58.0","version":"17.0.2.1"}
#Nextcloud <= 16
{"reqId":"Q4wX3I4LOUeuMV4wRK91","level":2,"time":"2019-04-03T22:14:11+00:00","remoteAddr":"10.11.12.13","user":"--","app":"core","method":"GET","url":"\/remote.php\/dav\/files","message":"Login failed: 'test' (Remote IP: '10.11.12.13')","userAgent":"Mozilla\/5.0 (X11; Ubuntu; Linux x86_64; rv:66.0) Gecko\/20100101 Firefox\/66.0","version":"15.0.5.3"}
Test: WebUI and Webdav
Running tests
=============
Use failregex filter file : nextcloud, basedir: /etc/fail2ban
Use log file : next.tmp
Use encoding : UTF-8
Results
=======
Failregex: 4 total
|- #) [# of hits] regular expression
| 1) [4] ^.*Login failed: '?.*'? \(Remote IP: '?<HOST>'?\).*$
`-
Ignoreregex: 0 total
Date template hits:
|- [# of hits] date format
| [4] ExYear(?P<_sep>[-/.])Month(?P=_sep)Day(?:T| ?)24hour:Minute:Second(?:[.,]Microseconds)?(?:\s*Zone offset)?
`-
Lines: 4 lines, 0 ignored, 4 matched, 0 missed
[processed in 0.02 sec]
|- Matched line(s):
| {"reqId":"BRHKHyh1lVFon5D33u4K","level":2,"time":"2020-01-13T12:34:00+00:00","remoteAddr":"10.11.12.13","user":"--","app":"no app in context","method":"POST","url":"\/index.php\/login","message":"Login failed: Tralololjlkl (Remote IP: 10.11.12.13)","userAgent":"Mozilla\/5.0 (Windows NT 10.0; Win64; x64; rv:72.0) Gecko\/20100101 Firefox\/72.0","version":"17.0.2.1"}
| {"reqId":"bFnTdevf7ZdCMQ5ddmNl","level":2,"time":"2019-04-03T21:49:30+00:00","remoteAddr":"10.11.12.13","user":"--","app":"core","method":"POST","url":"\/index.php\/login","message":"Login failed: 'Tralololjlkl' (Remote IP: '10.11.12.13')","userAgent":"Mozilla\/5.0 (X11; Ubuntu; Linux x86_64; rv:66.0) Gecko\/20100101 Firefox\/66.0","version":"15.0.5.3"}
| {"reqId":"lqdbtb7y3pZSv8sGM0mD","level":2,"time":"2020-01-26T22:20:32+00:00","remoteAddr":"10.11.12.13","user":"--","app":"core","method":"PUT","url":"\/remote.php\/webdav\/files","message":"Login failed: 'webdavlogin' (Remote IP: '10.11.12.13')","userAgent":"curl\/7.58.0","version":"17.0.2.1"}
| {"reqId":"Q4wX3I4LOUeuMV4wRK91","level":2,"time":"2019-04-03T22:14:11+00:00","remoteAddr":"10.11.12.13","user":"--","app":"core","method":"GET","url":"\/remote.php\/dav\/files","message":"Login failed: 'test' (Remote IP: '10.11.12.13')","userAgent":"Mozilla\/5.0 (X11; Ubuntu; Linux x86_64; rv:66.0) Gecko\/20100101 Firefox\/66.0","version":"15.0.5.3"}