I am getting different SSH attacks from the same IPs and they are getting banned. But they are using a different port and all they have to do is change the port to bypass the ban.
Dec 28 23:16:57 Nixie sshd[30706]: Failed password for root from 40.127.178.38 port 3424 ssh2
Dec 28 23:16:54 Nixie sshd[30704]: Failed password for root from 40.127.178.38 port 1112 ssh2
Dec 28 23:16:51 Nixie sshd[30702]: Failed password for root from 40.127.178.38 port 1116 ssh2
Dec 28 23:16:47 Nixie sshd[30700]: Failed password for root from 40.127.178.38 port 1115 ssh2
Dec 28 23:16:43 Nixie sshd[30698]: Failed password for root from 40.127.178.38 port 1114 ssh2
Dec 28 23:16:40 Nixie sshd[30696]: Failed password for root from 40.127.178.38 port 1113 ssh2
Dec 28 23:16:37 Nixie sshd[30694]: Failed password for root from 40.127.178.38 port 3424 ssh2
Dec 28 23:16:33 Nixie sshd[30692]: Failed password for root from 40.127.178.38 port 1112 ssh2
Here is my jail.local:
# 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.
#
# Comments: use '#' for comment lines and ';' for inline comments
#
# To avoid merges during upgrades DO NOT MODIFY THIS FILE
# and rather provide your changes in /etc/fail2ban/jail.local
#
# The DEFAULT allows a global definition of the options. They can be overridden
# in each jail afterwards.
[DEFAULT]
# "ignoreip" can be an IP address, a CIDR mask or a DNS host. Fail2ban will not
# ban a host which matches an address in this list. Several addresses can be
# defined using space separator.
ignoreip = 127.0.0.1/8
# "bantime" is the number of seconds that a host is banned.
bantime = 3600
# A host is banned if it has generated "maxretry" during the last "findtime"
# seconds.
findtime = 600
maxretry = 3
# "backend" specifies the backend used to get files modification.
# Available options are "pyinotify", "gamin", "polling" and "auto".
# This option can be overridden in each jail as well.
#
# pyinotify: requires pyinotify (a file alteration monitor) to be installed.
# If pyinotify is not installed, Fail2ban will use auto.
# gamin: requires Gamin (a file alteration monitor) to be installed.
# If Gamin is not installed, Fail2ban will use auto.
# polling: uses a polling algorithm which does not require external libraries.
# auto: will try to use the following backends, in order:
# pyinotify, gamin, polling.
backend = auto
# "usedns" specifies if jails should trust hostnames in logs,
# warn when reverse DNS lookups are performed, or ignore all hostnames in logs
#
# yes: if a hostname is encountered, a reverse DNS lookup will be performed.
# warn: if a hostname is encountered, a reverse DNS lookup will be performed,
# but it will be logged as a warning.
# no: if a hostname is encountered, will not be used for banning,
# but it will be logged as info.
usedns = warn
#
# Destination email address used solely for the interpolations in
# jail.{conf,local} configuration files.
destemail = root@localhost
#
# Name of the sender for mta actions
sendername = Fail2Ban
#
# ACTIONS
#
# Default banning action (e.g. iptables, iptables-new,
# iptables-multiport, shorewall, etc) It is used to define
# action_* variables. Can be overridden globally or per
# section within jail.local file
banaction = iptables-allports
# 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
# Specify chain where jumps would need to be added in iptables-* actions
chain = INPUT
#
# 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", chain="%(chain)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", chain="%(chain)s"]
%(mta)s-whois[name=%(__name__)s, dest="%(destemail)s", protocol="%(protocol)s", chain="%(chain)s", sendername="%(sendername)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", chain="%(chain)s"]
%(mta)s-whois-lines[name=%(__name__)s, dest="%(destemail)s", logpath=%(logpath)s, chain="%(chain)s", sendername="%(sendername)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
[dropbear]
enabled = false
port = ssh
filter = dropbear
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
# Here we use blackhole routes for not requiring any additional kernel support
# to store large volumes of banned IPs
[ssh-route]
enabled = false
filter = sshd
action = route
logpath = /var/log/sshd.log
maxretry = 6
# Here we use a combination of Netfilter/Iptables and IPsets
# for storing large volumes of banned IPs
#
# IPset comes in two versions. See ipset -V for which one to use
# requires the ipset package and kernel support.
[ssh-iptables-ipset4]
enabled = false
port = ssh
filter = sshd
banaction = iptables-ipset-proto4
logpath = /var/log/sshd.log
maxretry = 6
[ssh-iptables-ipset6]
enabled = false
port = ssh
filter = sshd
banaction = iptables-ipset-proto6
logpath = /var/log/sshd.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
# Ban attackers that try to use PHP's URL-fopen() functionality
# through GET/POST variables. - Experimental, with more than a year
# of usage in production environments.
[php-url-fopen]
enabled = false
port = http,https
filter = php-url-fopen
logpath = /var/www/*/logs/access_log
# A simple PHP-fastcgi jail which works with lighttpd.
# If you run a lighttpd server, then you probably will
# find these kinds of messages in your error_log:
# ALERT – tried to register forbidden variable ‘GLOBALS’
# through GET variables (attacker '1.2.3.4', file '/var/www/default/htdocs/index.php')
[lighttpd-fastcgi]
enabled = false
port = http,https
filter = lighttpd-fastcgi
logpath = /var/log/lighttpd/error.log
# Same as above for mod_auth
# It catches wrong authentifications
[lighttpd-auth]
enabled = false
port = http,https
filter = suhosin
logpath = /var/log/lighttpd/error.log
[nginx-http-auth]
enabled = true
filter = nginx-http-auth
port = http,https
logpath = /var/log/nginx/error.log
# Monitor roundcube server
[roundcube-auth]
enabled = false
filter = roundcube-auth
port = http,https
logpath = /var/log/roundcube/userlogins
[sogo-auth]
enabled = false
filter = sogo-auth
port = http, https
# without proxy this would be:
# port = 20000
logpath = /var/log/sogo/sogo.log
#
# 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
[pure-ftpd]
enabled = false
port = ftp,ftp-data,ftps,ftps-data
filter = pure-ftpd
logpath = /var/log/syslog
maxretry = 6
[wuftpd]
enabled = false
port = ftp,ftp-data,ftps,ftps-data
filter = wuftpd
logpath = /var/log/syslog
maxretry = 6
#
# Mail servers
#
[postfix]
enabled = false
port = smtp,ssmtp,submission
filter = postfix
logpath = /var/log/mail.log
[couriersmtp]
enabled = false
port = smtp,ssmtp,submission
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,submission,imap2,imap3,imaps,pop3,pop3s
filter = courierlogin
logpath = /var/log/mail.log
[sasl]
enabled = false
port = smtp,ssmtp,submission,imap2,imap3,imaps,pop3,pop3s
filter = postfix-sasl
# You might consider monitoring /var/log/mail.warn instead if you are
# running postfix since it would provide the same log lines at the
# "warn" level but overall at the smaller filesize.
logpath = /var/log/mail.log
[dovecot]
enabled = false
port = smtp,ssmtp,submission,imap2,imap3,imaps,pop3,pop3s
filter = dovecot
logpath = /var/log/mail.log
# To log wrong MySQL access attempts add to /etc/my.cnf:
# log-error=/var/log/mysqld.log
# log-warning = 2
[mysqld-auth]
enabled = false
filter = mysqld-auth
port = 3306
logpath = /var/log/mysqld.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 connection-less protocol, spoofing of IP and imitation
# 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
# Multiple jails, 1 per protocol, are necessary ATM:
# see https://github.com/fail2ban/fail2ban/issues/37
[asterisk-tcp]
enabled = false
filter = asterisk
port = 5060,5061
protocol = tcp
logpath = /var/log/asterisk/messages
[asterisk-udp]
enabled = false
filter = asterisk
port = 5060,5061
protocol = udp
logpath = /var/log/asterisk/messages
# Jail for more extended banning of persistent abusers
# !!! WARNING !!!
# Make sure that your loglevel specified in fail2ban.conf/.local
# is not at DEBUG level -- which might then cause fail2ban to fall into
# an infinite loop constantly feeding itself with non-informative lines
[recidive]
enabled = false
filter = recidive
logpath = /var/log/fail2ban.log
action = iptables-allports[name=recidive]
sendmail-whois-lines[name=recidive, logpath=/var/log/fail2ban.log]
bantime = 604800 ; 1 week
findtime = 86400 ; 1 day
maxretry = 5
Why aren't the IPs being blocked?
Here is my filter.d/sshd.conf
# Fail2Ban filter for openssh
#
[INCLUDES]
# Read common prefixes. If any customizations available -- read them from
# common.local
before = common.conf
[Definition]
_daemon = sshd
failregex = ^%(__prefix_line)s(?:error: PAM: )?[aA]uthentication (?:failure|error) for .* from <HOST>( via \S+)?\s*$
^%(__prefix_line)s(?:error: PAM: )?User not known to the underlying authentication module for .* from <HOST>\s*$
^%(__prefix_line)sFailed \S+ for .*? from <HOST>(?: port \d*)?(?: ssh\d*)?(: (ruser .*|(\S+ ID \S+ \(serial \d+\) CA )?\S+ %(__md5hex)s(, client user ".*", client host ".*")?))?\s*$
^%(__prefix_line)sROOT LOGIN REFUSED.* FROM <HOST>\s*$
^%(__prefix_line)s[iI](?:llegal|nvalid) user .* from <HOST>\s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because not listed in AllowUsers\s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because listed in DenyUsers\s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because not in any group\s*$
^%(__prefix_line)srefused connect from \S+ \(<HOST>\)\s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because a group is listed in DenyGroups\s*$
^%(__prefix_line)sUser .+ from <HOST> not allowed because none of user's groups are listed in AllowGroups\s*$
ignoreregex =
# DEV Notes:
#
# "Failed \S+ for .*? from <HOST>..." failregex uses non-greedy catch-all because
# it is coming before use of <HOST> which is not hard-anchored at the end as well,
# and later catch-all's could contain user-provided input, which need to be greedily
# matched away first.
#
# Author: Cyril Jaquier, Yaroslav Halchenko, Petr Voralek, Daniel Black
Output of iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
DROP all -- 43.229.53.66 anywhere
DROP all -- 58.218.211.38 anywhere
DROP all -- 124.173.68.198 anywhere
DROP all -- 183.56.173.20 anywhere
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Best Answer
It is quite possible that the
sshd.filter
does not match the lines you have. The filter I have installed would not match those lines. There is afail2ban-regex
utility that can be used to test your regex. A multi-line string in the regex contains multiple regexes, one per line.A regex like the following may match better. I think the existing regex is not finding enough data.
When testing you may have to define things like
__prefix_line
in the test script. Then try matching some records extracted from your log file.