Jak zmusi

[l.piwowarski]

Jak zmusić fail2ban do blokowania połączeń na innym porcie niż 22.
Sprawa pewnie bedzie prosta, sam jednak mimo długich poszukiwań niczego nie znalazłem.
Z góry dziekuję,

[genobis]

Jesteś pewien, że nie zadziała bez dodatkowej konfiguracji? Z tego co kojarzę, to chyba to nie powinno być konieczne.

[l.piwowarski]

Niestety nie działa.
Po nastawieniu maksymalnej ilości prób (maxfailures) na 3, i bantime=3600, przeładowaniu /etc/init.d/fail2ban restart zrobiłem test. Test polegał na wrzucieniu 4 głupich haseł. Przy podaniu 4-go system bodajże odbił próbę na starcie lecz bezpośrednio potem gdy (cały czas z tego samego ip) podano dobre hasło uzytkownik zostal zalogowany.

Niezaleznie od tego na http://www.the-art-of-web.com/system/fail2ban trafiłem na zdanie:

As soon as the deamon (fail2ban) is running your ssh port(22) will be protected from brute-force attacks

Oczywiście to może nie przesądzac sprawy ale myślę, że autor miał na myśli 22 (ten i tylko ten).

[wenu]

Witam.
Odświeżę temat.

Zainstalował fail2ban do ochrony ssh. Na ssh mam wysoki niestandardowy port. Określiłem maksymalnie 3 logowania błędne i mimo to nie działa.

Wypis z pliku konfiguracyjnego:

Kod: Zaznacz cały

[ssh]

enabled = true
port    = ssh
filter  = sshd
logpath  = /var/log/auth.log
maxretry = 3

Za opcję ,,port'' próbowałem wpisywać ,,mój port'' i też nic z tego. Oczywiście po każdej edycji robiłem restart.

[garnus]

Może w /etc/services zmień port dla ssh?

[wenu]

Zmienione wpisy w

Kod: Zaznacz cały

/etc/services

Restart fail2ban i nadal nie blokuje mnie po 3 razy (tyle ustawiłem).

[lessmian2]

Zmiana tego w /etc/services jest moim zdaniem, delikatnie mówiąc, głupim pomysłem. Port można to zdefiniować w konfiguracji fail2ban w pliku /etc/fail2ban/jail.conf - sekcja ssh.

[wenu]

Też tak próbowałem:

Kod: Zaznacz cały

# 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 <[email protected]>
#
# $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  = 30
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 = 

#
# 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 = true
port    = ssh
filter    = sshd
logpath  = /var/log/auth.log
maxretry = 3

# 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
#

[courierauth]

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


[sasl]

enabled  = false
port     = smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
filter   = sasl
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

# Word of Caution:
# Given filter can lead to DoS attack against your DNS server
# since there is no way to assure that UDP packets come from the
# real source IP
[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

W miejscu port zamaist ssh wstawiałem moj port i nadal zero reakcji.

Plik z logami logowań ssh istnieje.

Dodane:

Kod: Zaznacz cały

2011-01-24 23:13:43,155 fail2ban.actions.action: ERROR  iptables -N fail2ban-ssh
iptables -A fail2ban-ssh -j RETURN
iptables -I INPUT -p tcp -m multiport --dports ssh -j fail2ban-ssh returned 300

[garnus]

Zmiana tego w /etc/services jest moim zdaniem, delikatnie mówiąc, głupim pomysłem. Port można to zdefiniować w konfiguracji fail2ban w pliku /etc/fail2ban/jail.conf - sekcja ssh.

Rzucić że głupio to łatwo ale dlaczego to już nie łaska napisać?

[lessmian2]

Ponieważ, bo - wszystkie inne usługi i programy łącząc się gdzieś poprzez ssh i używając ,,ssh'' zamiast numeru portu, będą używały tego niestandardowego zdefiniowanego w /etc/services, a Ty będziesz szukał dwa dni czemu to nie działa. Tam jest mapowanie nazw usług na domyślne porty i lepiej żeby tak zostało.