fail2ban

Utilisant ssh pour maintenir les PC de mes proches (famille, amis...)=20
j'ai install=E9 pour parer aux attaques par force brute.

Environnement : Debian testing, Freebox en mode routeur (les ports qui=20
vont bien redirig=E9s sur ma machine), pas d'autre firewall pour le momen=
t.

Installation apparament sans pb, fichier de conf par d=E9faut accept=E9=20
(joint ci-dessous).

Sauf que =E7a marche pas...

Depuis chez ma m=E8re j'ai tente plusieurs connexion avec de mauvais mots=
=20
de passe sans jamais =EAtre banni. Pire, aucune trace dans le fichier de =

log (voir ci-dessous).

J'ai du louper quelque-chose, oui mais o=F9 ?

R=E9sultats des commandes :

# /etc/init.d/fail2ban status
* Status of authentication failure monitor=20
=20

* fail2ban is running



# iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
fail2ban-ssh tcp -- anywhere anywhere=20
multiport dports ssh,sftp

Chain FORWARD (policy ACCEPT)
target prot opt source destination

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

Chain fail2ban-ssh (1 references)
target prot opt source destination
RETURN 0 -- anywhere anywhere

# zcat /var/log/auth.log* | grep 'Failed password' | grep sshd | awk=20
'{print $1,$2}' | sort | uniq -c

zcat: /var/log/auth.log: not in gzip format

zcat: /var/log/auth.log.0: not in gzip format
10 May 22
28 May 24
34 May 26
2 May 29

(aucune trace de mes tentatives de cet apr=E8s-midi)


Fichier /etc/fail2ban/jail.conf
# 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 <debian@onerussian.com>
#
# $Revision: 281 $
#

# The DEFAULT allows a global definition of the options. They can be=20
override
# in each jail afterwards.

[DEFAULT]

# "ignoreip" can be an IP address, a CIDR mask or a DNS host
ignoreip =3D 127.0.0.1
bantime =3D 600
maxretry =3D 3

# "backend" specifies the backend used to get files modification. Availab=
le
# options are "gamin", "polling" and "auto".
# yoh: For some reason Debian shipped python-gamin didn't work as expecte=
d
# This issue left ToDo, so polling is default backend for now
backend =3D polling

#
# Destination email address used solely for the interpolations in
# jail.{conf,local} configuration files.
destemail =3D vgay@salug-fr.org

#
# 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 =3D iptables-multiport


#
# Action shortcuts. To be used to define action parameter

# The simplest action to take: ban only
action_ =3D %(banaction)s[name=3D%(__name__)s, port=3D"%(port)s"]

# ban & send an e-mail with whois report to the destemail.
action_mw =3D %(banaction)s[name=3D%(__name__)s, port=3D"%(port)s"]
mail-whois[name=3D%(__name__)s, dest=3D"%(destemail)s"]

# ban & send an e-mail with whois report and relevant log lines
# to the destemail.
action_mwl =3D %(banaction)s[name=3D%(__name__)s, port=3D"%(port)s"]
mail-whois-lines[name=3D%(__name__)s,=20
dest=3D"%(destemail)s", logpath=3D%(logpath)s]

# Choose default action. To change, just override value of 'action'=20
with the
# interpolation to the chosen action shortcut (e.g. action_mw,=20
action_mwl, etc) in jail.local
# globally (section [DEFAULT]) or per specific section
action =3D %(action_)s

#
# JAILS
#

# Next jails corresponds to the standard configuration in Fail2ban 0.6 wh=
ich
# was shipped in Debian. Please enable any defined here jail by including=

#
# [SECTION_NAME]
# enabled =3D 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 =3D true
port =3D ssh,sftp
filter =3D sshd
logpath =3D /var/log/auth.log
maxretry =3D 6


[ssh-ddos]

enabled =3D false
port =3D ssh,sftp
filter =3D sshd-ddos
logpath =3D /var/log/auth.log
maxretry =3D 6

#
# HTTP servers
#

[apache]

enabled =3D false
port =3D http,https
filter =3D apache-auth
logpath =3D /var/log/apache*/*access.log
maxretry =3D 6

# default action is now multiport, so apache-multiport jail was left
# for compatibility with previous (<0.7.6-2) releases
[apache-multiport]

enabled =3D false
port =3D http,https
filter =3D apache-auth
logpath =3D /var/log/apache*/*access.log
maxretry =3D 6

[apache-noscript]

enabled =3D false
port =3D http,https
filter =3D apache-noscript
logpath =3D /var/log/apache*/*error.log
maxretry =3D 6

#
# FTP servers
#

[vsftpd]

enabled =3D false
port =3D ftp,ftp-data,ftps,ftps-data
filter =3D vsftpd
logpath =3D /var/log/vsftpd.log
# or overwrite it in jails.local to be
# logpath =3D /var/log/auth.log
# if you want to rely on PAM failed login attempts
# vsftpd's failregex should match both of those formats
maxretry =3D 6


[proftpd]

enabled =3D false
port =3D ftp,ftp-data,ftps,ftps-data
filter =3D proftpd
logpath =3D /var/log/proftpd/proftpd.log
maxretry =3D 6


[wuftpd]

enabled =3D false
port =3D ftp,ftp-data,ftps,ftps-data
filter =3D wuftpd
logpath =3D /var/log/auth.log
maxretry =3D 6


#
# Mail servers
#

[postfix]

enabled =3D false
port =3D smtp,ssmtp
filter =3D postfix
logpath =3D /var/log/mail.log


[couriersmtp]

enabled =3D false
port =3D smtp,ssmtp
filter =3D couriersmtp
logpath =3D /var/log/mail.log


#
# Mail servers authenticators: might be used for smtp,ftp,imap servers, s=
o
# all relevant ports get banned
#

[courierauth]

enabled =3D false
port =3D smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
filter =3D courierlogin
logpath =3D /var/log/mail.log


[sasl]

enabled =3D false
port =3D smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
filter =3D sasl
logpath =3D /var/log/mail.log


Merci d'avance


--=20
Vincent Gay - mailto:vgay@salug-fr.org
"Il y a assez de tout dans le monde pour satisfaire aux besoins de=20
l'homme, mais pas assez pour assouvir son avidit=E9". (Gandhi)