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lpi2:fail2ban [2016/12/09 12:22] – ingo_wichmannlpi2:fail2ban [2026/01/10 22:35] (aktuell) – ingo_wichmann
Zeile 1: Zeile 1:
 Pakete:  Pakete: 
-  * Debian (ab 7): ''fail2ban''+  * Debian (ab 12): ''fail2ban python3-pyinotify python3-systemd''
  
 Per default überwacht fail2ban bei debian ssh: Per default überwacht fail2ban bei debian ssh:
  
-  grep -A7 '\[ssh\]' /etc/fail2ban/jail.conf+  egrep -A7 '\[sshd?\]' /etc/fail2ban/jail.conf
   less /etc/fail2ban/filter.d/sshd.conf   less /etc/fail2ban/filter.d/sshd.conf
  
Zeile 16: Zeile 16:
  
   less /etc/fail2ban/action.d/iptables-multiport.conf   less /etc/fail2ban/action.d/iptables-multiport.conf
 +
 +fail2ban Zusammenfassung der Konfiguration anzeigen:
 +  fail2ban-client status
 +  fail2ban-client status sshd
 +
 +====== Apache Basic Auth ======
 +Pakete: apache2 fail2ban (Debian 9)
 +
 +  mkdir -p /srv/www/fail2ban
 +  htpasswd -c /srv/www/htpasswd_fail2ban heinz
 +
 +<file txt /etc/apache2/conf-available/fail2ban-apache-auth-test.conf>
 +<directory /srv/www/fail2ban>
 +  AllowOverride AuthConfig
 +  AuthType        Basic
 +  AuthName        "Bitte Username und Passwort"
 +  AuthBasicProvider file
 +  AuthUserFile    /srv/www/htpasswd_fail2ban
 +  Require         valid-user
 +</directory>
 +</file>
 +
 +<file html /srv/www/fail2ban/index.html>
 +<html>
 +  <head>
 +    <title>Hello fail2ban!</title>
 +  </head>
 +  <body>
 +    Hello fail2ban
 +  </body>
 +</html>
 +</file>
 +
 +Zugriff lokal testen:
 +  wget --user heinz --password xxx -nv -O - http://127.0.0.1/fail2ban-test/index.html
 +
 +<file txt /etc/fail2ban/jail.local>
 +[apache-auth]
 +enabled = true
 +</file>
 +
 +  fail2ban-client reload
 +  fail2ban-client status
 +  fail2ban-client status apache-auth
 +
 +Von einem anderen Rechner aus:
 +  ab -n 10 -A heinz:nono http://192.168.212.11/fail2ban-test/index.html
 +
 +  less /var/log/fail2ban.log
 +
 +====== Apache Log mit HTTP Status 400 (Bad Request) ======
 +Beispiel für Zeile aus ''access.log'' mit Status 400:
 +
 +<file txt /var/log/apache/access.log>
 +server.example.org:80 139.162.173.209 - - [10/Jan/2026:21:10:46 +0000] "GET default.asp HTTP/1.1" 400 444 "-" "-"
 +</file>
 +
 +===== Filter =====
 +<file txt /etc/fail2ban/filter.d/apache-badrequest.local>
 +[Definition]
 +failregex = ^\S+ <ADDR> - - \[[^\]]*\] "[^"]+" 400
 +</file> (( ''<ADDR>'' siehe 
 +^Tag^Description^Example regex in filter file^
 +|<HOST>|Matches IPv4/IPv6 address or hostname|''^Failed login from <HOST>$''|
 +|<IP4>|Matches IPv4 address only|''^Failed login from <IP4>$''|
 +|<IP6>|Matches IPv6 address only|''^Failed login from <IP6>$''|
 +|<ADDR>|Matches IPv4/IPv6 address (no hostname)|''^Connection from <ADDR>$''|
 +|<SUBNET>|Matches IP with optional CIDR notation|''^Connection from <SUBNET>$''|
 +|<F-USER>...</F-USER>|Captures a username|''^Failed login for <F-USER>\S+</F-USER>$''|
 +|<F-ID>...</F-ID>|Captures a failure ID|''^Error <F-ID>\d+</F-ID> from <HOST>$''|
 +|<SKIPLINES>|Used for multi-line matching|''^Start pattern$<SKIPLINES>^End pattern$''|
 +))
 +
 +Filter testen:
 +  fail2ban-regex 'server.example.org:80 139.162.173.209 - - [10/Jan/2026:21:10:46 +0000] "GET default.asp HTTP/1.1" 400 444 "-" "-"' /etc/fail2ban/filter.d/apache-badrequest.local
 +-> sollte ''1 matched'' ausgeben
 +
 +  fail2ban-regex /var/log/apache2/access.log /etc/fail2ban/filter.d/apache-badrequest.local
 +-> sollte die korrekte Anzahl Zeilen mit Status 400 ausgeben.
 +
 +===== Jail =====
 +
 +<file txt /etc/fail2ban/jail.d/apache-badrequest.local>
 +[apache_bad_request]
 +enabled = true
 +port    = http,https
 +filter  = apache-badrequest
 +logpath = /var/log/apache*/*access.log
 +maxretry = 3
 +</file>
 +
 +Testen:
 +  fail2ban-client reload
 +-> ''OK''
 +  fail2ban-client status
 +-> ''Jail list: … apache_bad_request…''
 +  fail2ban-client status apache_bad_request
  
lpi2/fail2ban.1481286160.txt.gz · Zuletzt geändert: 2016/12/09 12:22 von ingo_wichmann