Ok, ora le cose si complicano un pochino: Il file è semplicemente molto lungo ma strutturato bene e semplice da capire.
Il file “jail.conf” contiene le impostazioni predefinite del tool. E’ strutturato in sezioni corrispondenti alle jail configurate. “[DEFAULT]” contiene le impostazioni comuni per tutte le jail salvo diversa indicazione.
Le “jail” hanno tutte una struttura simile alla seguente:
codice:
[roundcube-iredmail]
enabled = true
filter = roundcube.iredmail
action = iptables-multiport[name=roundcube, port="ssh,http,https,smtp,smtps,pop3,pop3s,imap,imaps,sieve", protocol=tcp]
logpath = /var/log/maillog
findtime = 3600
maxretry = 5
bantime = 3600
Ogni jail contiene una riga “enabled” che la attiva o disattiva, una riga “filter” che indica a quale file presente nella sottodirectory “filter.d” contiene la regex da applicare ed una riga “action” che definisce le azioni da intraprendere in caso di match positivo, richiamando gli script contenuti nella sottodirectory “action.d”. Le altre opzioni possono essere recuperate dalle indicazioni riportate per la jail [DEFAULT] oppure specificate esplicitamente per applicare un valore diverso dal predefinito.
Tutte le altre jail contenute nel files sono disabilitate quindi servono solo come base di partenza per la creazione di una configurazione personalizzata. Questo files, come detto, non dovrebbe mai essere modificato:
codice:
Fail2Ban configuration file.
#
# This file was composed for Debian systems from the original one
# provided now under /usr/share/doc/fail2ban/examples/jail.conf
# for additional examples.
#
# To avoid merges during upgrades DO NOT MODIFY THIS FILE
# and rather provide your changes in /etc/fail2ban/jail.local
#
# Author: Yaroslav O. Halchenko
#
# $Revision: 281 $
#
# The DEFAULT allows a global definition of the options. They can be override
# in each jail afterwards.
[DEFAULT]
# "ignoreip" can be an IP address, a CIDR mask or a DNS host
ignoreip = 127.0.0.1
bantime = 600
maxretry = 3
# "backend" specifies the backend used to get files modification. Available
# options are "gamin", "polling" and "auto".
# yoh: For some reason Debian shipped python-gamin didn't work as expected
# This issue left ToDo, so polling is default backend for now
backend = polling
#
# Destination email address used solely for the interpolations in
# jail.{conf,local} configuration files.
destemail = root@localhost
#
# ACTIONS
#
# Default banning action (e.g. iptables, iptables-new,
# iptables-multiport, shorewall, etc) It is used to define
# action_* variables. Can be overriden globally or per
# section within jail.local file
banaction = iptables-multiport
# email action. Since 0.8.1 upstream fail2ban uses sendmail
# MTA for the mailing. Change mta configuration parameter to mail
# if you want to revert to conventional 'mail'.
mta = sendmail
# Default protocol
protocol = tcp
#
# Action shortcuts. To be used to define action parameter
# The simplest action to take: ban only
action_ = %(banaction)s[name=%(__name__)s, port="%(port)s", protocol="%(protocol)s]
# ban & send an e-mail with whois report to the destemail.
action_mw = %(banaction)s[name=%(__name__)s, port="%(port)s", protocol="%(protocol)s]
%(mta)s-whois[name=%(__name__)s, dest="%(destemail)s", protocol="%(protocol)s]
# ban & send an e-mail with whois report and relevant log lines
# to the destemail.
action_mwl = %(banaction)s[name=%(__name__)s, port="%(port)s", protocol="%(protocol)s]
%(mta)s-whois-lines[name=%(__name__)s, dest="%(destemail)s", logpath=%(logpath)s]
# Choose default action. To change, just override value of 'action' with the
# interpolation to the chosen action shortcut (e.g. action_mw, action_mwl, etc) in jail.local
# globally (section [DEFAULT]) or per specific section
action = %(action_)s
#
# JAILS
#
# Next jails corresponds to the standard configuration in Fail2ban 0.6 which
# was shipped in Debian. Enable any defined here jail by including
#
# [SECTION_NAME]
# enabled = true
#
# in /etc/fail2ban/jail.local.
#
# Optionally you may override any other parameter (e.g. banaction,
# action, port, logpath, etc) in that section within jail.local
[ssh]
enabled = false
port = ssh
filter = sshd
logpath = /var/log/auth.log
maxretry = 6
# Generic filter for pam. Has to be used with action which bans all ports
# such as iptables-allports, shorewall
[pam-generic]
enabled = false
# pam-generic filter can be customized to monitor specific subset of 'tty's
filter = pam-generic
# port actually must be irrelevant but lets leave it all for some possible uses
port = all
banaction = iptables-allports
port = anyport
logpath = /var/log/auth.log
maxretry = 6
[xinetd-fail]
enabled = false
filter = xinetd-fail
port = all
banaction = iptables-multiport-log
logpath = /var/log/daemon.log
maxretry = 2
[ssh-ddos]
enabled = false
port = ssh
filter = sshd-ddos
logpath = /var/log/auth.log
maxretry = 6
#
# HTTP servers
#
[apache]
enabled = false
port = http,https
filter = apache-auth
logpath = /var/log/apache*/*error.log
maxretry = 6
# default action is now multiport, so apache-multiport jail was left
# for compatibility with previous (<0.7.6-2) releases
[apache-multiport]
enabled = false
port = http,https
filter = apache-auth
logpath = /var/log/apache*/*error.log
maxretry = 6
[apache-noscript]
enabled = false
port = http,https
filter = apache-noscript
logpath = /var/log/apache*/*error.log
maxretry = 6
[apache-overflows]
enabled = false
port = http,https
filter = apache-overflows
logpath = /var/log/apache*/*error.log
maxretry = 2
#
# FTP servers
#
[vsftpd]
enabled = false
port = ftp,ftp-data,ftps,ftps-data
filter = vsftpd
logpath = /var/log/vsftpd.log
# or overwrite it in jails.local to be
# logpath = /var/log/auth.log
# if you want to rely on PAM failed login attempts
# vsftpd's failregex should match both of those formats
maxretry = 6
[proftpd]
enabled = false
port = ftp,ftp-data,ftps,ftps-data
filter = proftpd
logpath = /var/log/proftpd/proftpd.log
maxretry = 6
[wuftpd]
enabled = false
port = ftp,ftp-data,ftps,ftps-data
filter = wuftpd
logpath = /var/log/auth.log
maxretry = 6
#
# Mail servers
#
[postfix]
enabled = false
port = smtp,ssmtp
filter = postfix
logpath = /var/log/mail.log
[couriersmtp]
enabled = false
port = smtp,ssmtp
filter = couriersmtp
logpath = /var/log/mail.log
#
# Mail servers authenticators: might be used for smtp,ftp,imap servers, so
# all relevant ports get banned
#
[sasl]
enabled = false
port = smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
filter = sasl
# You might consider monitoring /var/log/warn.log instead
# if you are running postfix. See http://bugs.debian.org/507990
logpath = /var/log/mail.log
# DNS Servers
# These jails block attacks against named (bind9). By default, logging is off
# with bind9 installation. You will need something like this:
#
# logging {
# channel security_file {
# file "/var/log/named/security.log" versions 3 size 30m;
# severity dynamic;
# print-time yes;
# };
# category security {
# security_file;
# };
# };
#
# in your named.conf to provide proper logging
# !!! WARNING !!!
# Since UDP is connectionless protocol, spoofing of IP and immitation
# of illegal actions is way too simple. Thus enabling of this filter
# might provide an easy way for implementing a DoS against a chosen
# victim. See
# http://nion.modprobe.de/blog/archives/690-fail2ban-+-dns-fail.html
# Please DO NOT USE this jail unless you know what you are doing.
#[named-refused-udp]
#
#enabled = false
#port = domain,953
#protocol = udp
#filter = named-refused
#logpath = /var/log/named/security.log
[named-refused-tcp]
enabled = false
port = domain,953
protocol = tcp
filter = named-refused
logpath = /var/log/named/security.log
Ho però già un file "jail.local" creato da iredmail con il seguente contenuto:
codice:
# File generated by iRedMail (2012.08.24.12.54.28):
#
# Version: 0.8.1
# Project: http://www.iredmail.org/
#
# Community: http://www.iredmail.org/forum/
#
# Please refer to /etc/fail2ban/jail.conf for more examples.
[ssh-iredmail]
enabled = true
filter = sshd
action = iptables[name=ssh, port="ssh", protocol=tcp]
# sendmail-whois[name=ssh, dest=root, sender=fail2ban@mail.com]
logpath = /var/log/auth.log
maxretry = 5
#ignoreip = 127.0.0.1
[roundcube-iredmail]
enabled = true
filter = roundcube.iredmail
action = iptables-multiport[name=roundcube, port="http,https,smtp,submission,pop3,pop3s,imap,imaps,sieve", protocol=tcp]
logpath = /var/log/mail.log
findtime = 3600
maxretry = 5
bantime = 3600
ignoreip = 127.0.0.1
[dovecot-iredmail]
enabled = true
filter = dovecot.iredmail
action = iptables-multiport[name=dovecot, port="http,https,smtp,submission,pop3,pop3s,imap,imaps,sieve", protocol=tcp]
logpath = /var/log/dovecot.log
maxretry = 5
findtime = 300
bantime = 3600
ignoreip = 127.0.0.1
[postfix-iredmail]
enabled = true
filter = postfix.iredmail
action = iptables-multiport[name=postfix, port="http,https,smtp,submission,pop3,pop3s,imap,imaps,sieve", protocol=tcp]
# sendmail[name=Postfix, dest=you@mail.com]
logpath = /var/log/mail.log
bantime = 3600
maxretry = 5
ignoreip = 127.0.0.1