Configuration de fail2ban selon les différentes versions d’asterisk

Fail2ban est un outil indispensable à installer sur ses serveurs asterisk. Il permet de bloquer de manière proactive les tentatives de scan et ainsi de protéger vos deniers. Mais selon la version d’asterisk, le filtre doit être configurer de manière différente.

Il faut ajouter au fichier jail.conf la partie le code suivant :

[asterisk-iptables]
# if more than 4 attempts are made within 6 hours, ban for 24 hours
enabled  = true
filter   = asterisk
action   = iptables-allports[name=ASTERISK, protocol=all]
              sendmail[name=ASTERISK, dest=, sender=]
logpath  = /var/log/asterisk/messages
maxretry = 4
findtime = 21600
bantime = 86400

et créer le fichier suivant :

filter.d/asterisk.conf

et copier le code suivant pour asterisk 1.4 et 1.6 :

# Fail2Ban configuration file
#
#
# $Revision: 251 $
#

[INCLUDES]

# Read common prefixes. If any customizations available -- read them from
# common.local
before = common.conf

[Definition]

#_daemon = asterisk

# Option:  failregex
# Notes.:  regex to match the password failures messages in the logfile. The
#          host must be matched by a group named "host". The tag "<HOST>" can
#          be used for standard IP/hostname matching and is only an alias for
#          (?:::f{4,6}:)?(?P<host>S+)
# Values:  TEXT
#

failregex = NOTICE.* .*: Registration from '.*' failed for '<HOST>' - Wrong password
            NOTICE.* .*: Registration from '.*' failed for '<HOST>' - No matching peer found
            NOTICE.* .*: Registration from '.*' failed for '<HOST>' - Username/auth name mismatch
            NOTICE.* <HOST> failed to authenticate as '.*'$
            NOTICE.* .*: No registration for peer '.*' (from )
            NOTICE.* .*: Host  failed MD5 authentication for '.*' (.*)
            NOTICE.* .*: Registration from '.*' failed for '<HOST>' - Device does not match ACL
            NOTICE.* .*: Registration from '.*" .* failed for '<HOST>' - Peer is not supposed to register
            VERBOSE.*SIP/<HOST>-.*Received incoming SIP connection from unknown peer

# Option:  ignoreregex
# Notes.:  regex to ignore. If this regex matches, the line is ignored.
# Values:  TEXT
#
ignoreregex =

et pour la version 1.8, le code suivant :

# Fail2Ban configuration file
#
#
# $Revision: 251 $
#

[INCLUDES]

# Read common prefixes. If any customizations available -- read them from
# common.local
before = common.conf

[Definition]

#_daemon = asterisk

# Option:  failregex
# Notes.:  regex to match the password failures messages in the logfile. The
#          host must be matched by a group named "host". The tag "<HOST>" can
#          be used for standard IP/hostname matching and is only an alias for
#          (?:::f{4,6}:)?(?P<host>S+)
# Values:  TEXT
#
# Asterisk 1.8 uses Host:Port format which is reflected here

failregex = NOTICE.* .*: Registration from '.*' failed for '<HOST>:.*' - Wrong password
            NOTICE.* .*: Registration from '.*' failed for '<HOST>:.*' - No matching peer found
            NOTICE.* .*: Registration from '.*' failed for '<HOST>:.*' - No matching peer found
            NOTICE.* .*: Registration from '.*' failed for '<HOST>:.*' - Username/auth name mismatch
            NOTICE.* .*: Registration from '.*' failed for '<HOST>:.*' - Device does not match ACL
            NOTICE.* .*: Registration from '.*' failed for '<HOST>:.*' - Peer is not supposed to register
            NOTICE.* .*: Registration from '.*' failed for '<HOST>:.*' - ACL error (permit/deny)
            NOTICE.* .*: Registration from '.*' failed for '<HOST>:.*' - Device does not match ACL
            NOTICE.* .*: Registration from '".*".*' failed for '<HOST>:.*' - No matching peer found
            NOTICE.* .*: Registration from '".*".*' failed for '<HOST>:.*' - Wrong password
            NOTICE.* <HOST> failed to authenticate as '.*'$
            NOTICE.* .*: No registration for peer '.*' (from <HOST>)
            NOTICE.* .*: Host <HOST> failed MD5 authentication for '.*' (.*)
            NOTICE.* .*: Failed to authenticate user .*@<HOST>.*
            NOTICE.* .*: <HOST> failed to authenticate as '.*'
            NOTICE.* .*: <HOST> tried  to authenticate with nonexistent user '.*'
            VERBOSE.*SIP/<HOST>-.*Received incoming SIP connection from unknown peer

# Option:  ignoreregex
# Notes.:  regex to ignore. If this regex matches, the line is ignored.
# Values:  TEXT
#
ignoreregex =

Ce code fonctionne pour asterisk 10 et 11 même si je bosse sur une amélioration.

Auteur : Mathias

Qui suis-je ? Je travaille dans les télécoms et réseaux depuis 1996 (oui, le siècle dernier). Je suis ingénieur en génie électrique et informatique industrielle réseaux et télécoms. Je suis passionné de technologies et je participe à plusieurs projets touchant les télécoms (asterisk et freeswitch notament) et la sécurité informatique (PfSense). J’interviens en tant que freelance afin d'accompagner les entreprises et opérateurs en leur apportant mon expérience et mon expertise.

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