最近，我的经理在我们的 ubuntu 10.04 电子邮件服务器上安装了 fail2ban，以禁止无法通过电子邮件服务器验证的 IP 地址。当我们监控系统时，我们没有看到被 fail2ban 禁止的不断尝试在我们的系统上进行验证的 IP。我们做错了什么？以下是 conf 文件：
fail2ban.conf
# Fail2Ban configuration file
#
# Author: Cyril Jaquier
#
# $Revision: 629 $
#
[Definition]
# Option: loglevel
# Notes.: Set the log level output.
# 1 = ERROR
# 2 = WARN
# 3 = INFO
# 4 = DEBUG
# Values: NUM Default: 3
#
loglevel = 3
# Option: logtarget
# Notes.: Set the log target. This could be a file, SYSLOG, STDERR or STDOUT.
# Only one log target can be specified.
# Values: STDOUT STDERR SYSLOG file Default: /var/log/fail2ban.log
#
logtarget = /var/log/fail2ban.log
# Option: socket
# Notes.: Set the socket file. This is used to communicate with the daemon. Do
# not remove this file when Fail2ban runs. It will not be possible to
# communicate with the server afterwards.
# Values: FILE Default: /var/run/fail2ban/fail2ban.sock
#
socket = /var/run/fail2ban/fail2ban.sock
监狱配置文件- 仅启用后缀和 sasl 过滤器
# 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
# 12/17/19 added to line below: /8
ignoreip = 127.0.0.1/8
bantime = -1
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
# 12/17/19 changed from: polling to: auto
backend = auto
#
# 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 line below on 12/17/19 by Jesus
enabled = true
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 = true
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
# 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
postfix配置文件
# Fail2Ban configuration file
#
# Author: Cyril Jaquier
#
# $Revision: 728 $
#
[Definition]
# 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>[\w\-.^_]+)
# Values: TEXT
#
failregex = reject: RCPT from (.*)\[<HOST>\]: 554
# Option: ignoreregex
# Notes.: regex to ignore. If this regex matches, the line is ignored.
# Values: TEXT
#
ignoreregex =
sasl配置文件
# Fail2Ban configuration file
#
# Author: Yaroslav Halchenko
#
# $Revision: 728 $
#
[Definition]
# 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>[\w\-.^_]+)
# Values: TEXT
#
failregex = (?i): warning: [-._\w]+\[<HOST>\]: SASL (?:LOGIN|PLAIN|(?:CRAM|DIGEST)-MD5) authentication failed(: [A-Za-z0-9+/]*={0,2})?$
# Option: ignoreregex
# Notes.: regex to ignore. If this regex matches, the line is ignored.
# Values: TEXT
#
ignoreregex =
部分日志文件条目（/var/log/mail.log）
Jan 7 08:03:26 mail postfix/smtpd[29218]: warning: 78.128.113.86: address not listed for hostname ip-113-86.4vendeta.com
Jan 7 08:03:26 mail postfix/smtpd[29218]: connect from unknown[78.128.113.86]
Jan 7 08:03:28 mail postfix/smtpd[29218]: warning: SASL authentication failure: Password verification failed
Jan 7 08:03:28 mail postfix/smtpd[29218]: warning: unknown[78.128.113.86]: SASL PLAIN authentication failed: authentication failure
Jan 7 08:03:28 mail postfix/smtpd[29218]: lost connection after AUTH from unknown[78.128.113.86]
Jan 7 08:03:28 mail postfix/smtpd[29218]: disconnect from unknown[78.128.113.86]
Jan 7 08:03:29 mail postfix/smtpd[29218]: warning: 78.128.113.86: address not listed for hostname ip-113-86.4vendeta.com
Jan 7 08:03:29 mail postfix/smtpd[29218]: connect from unknown[78.128.113.86]
Jan 7 08:03:30 mail postfix/smtpd[29218]: warning: SASL authentication failure: Password verification failed
Jan 7 08:03:30 mail postfix/smtpd[29218]: warning: unknown[78.128.113.86]: SASL PLAIN authentication failed: authentication failure
Jan 7 08:03:31 mail postfix/smtpd[29218]: lost connection after AUTH from unknown[78.128.113.86]
Jan 7 08:03:31 mail postfix/smtpd[29218]: disconnect from unknown[78.128.113.86]
Jan 7 08:08:02 mail postfix/smtpd[29254]: warning: 80.66.81.86: address not listed for hostname host86.at-sib.ru
Jan 7 08:08:02 mail postfix/smtpd[29254]: connect from unknown[80.66.81.86]
Jan 7 08:08:07 mail postfix/smtpd[29254]: warning: unknown[80.66.81.86]: SASL LOGIN authentication failed: authentication failure
Jan 7 08:08:08 mail postfix/smtpd[29254]: lost connection after AUTH from unknown[80.66.81.86]
Jan 7 08:08:08 mail postfix/smtpd[29254]: disconnect from unknown[80.66.81.86]
Jan 7 08:08:08 mail postfix/smtpd[29254]: warning: 80.66.81.86: address not listed for hostname host86.at-sib.ru
Jan 7 08:08:08 mail postfix/smtpd[29254]: connect from unknown[80.66.81.86]
Jan 7 08:08:12 mail postfix/smtpd[29254]: warning: unknown[80.66.81.86]: SASL LOGIN authentication failed: authentication failure
Jan 7 08:08:13 mail postfix/smtpd[29254]: lost connection after AUTH from unknown[80.66.81.86]
Jan 7 08:08:13 mail postfix/smtpd[29254]: disconnect from unknown[80.66.81.86]
Jan 7 08:08:41 mail postfix/smtpd[29254]: warning: 80.66.81.143: address not listed for hostname host143.at-sib.ru
Jan 7 08:08:41 mail postfix/smtpd[29254]: connect from unknown[80.66.81.143]
Jan 7 08:08:46 mail postfix/smtpd[29254]: warning: unknown[80.66.81.143]: SASL LOGIN authentication failed: authentication failure
Jan 7 08:08:47 mail postfix/smtpd[29254]: lost connection after AUTH from unknown[80.66.81.143]
Jan 7 08:08:47 mail postfix/smtpd[29254]: disconnect from unknown[80.66.81.143]
Jan 7 08:08:47 mail postfix/smtpd[29254]: warning: 80.66.81.143: address not listed for hostname host143.at-sib.ru
Jan 7 08:08:47 mail postfix/smtpd[29254]: connect from unknown[80.66.81.143]
Jan 7 08:08:52 mail postfix/smtpd[29254]: warning: unknown[80.66.81.143]: SASL LOGIN authentication failed: authentication failure
Jan 7 08:08:53 mail postfix/smtpd[29254]: lost connection after AUTH from unknown[80.66.81.143]
Jan 7 08:08:53 mail postfix/smtpd[29254]: disconnect from unknown[80.66.81.143]
fail2ban-客户端状态输出
$ sudo fail2ban-client status
Status
|- Number of jail: 2
`- Jail list: postfix, sasl
postfix 的 fail2ban-client 输出
$ sudo fail2ban-client status postfix
Status for the jail: postfix
|- filter
| |- File list: /var/log/mail.log
| |- Currently failed: 0
| `- Total failed: 69
`- action
|- Currently banned: 1
| `- IP list: 185.208.211.185
`- Total banned: 1
sasl 的 fail2ban-client 输出
$ sudo fail2ban-client status sasl
Status for the jail: sasl
|- filter
| |- File list: /var/log/mail.log
| |- Currently failed: 0
| `- Total failed: 0
`- action
|- Currently banned: 0
| `- IP list:
`- Total banned: 0
iptables输出
$ sudo iptables -L
Chain INPUT (policy ACCEPT)
target prot opt source destination
fail2ban-sasl tcp -- anywhere anywhere multiport dports smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
fail2ban-postfix tcp -- anywhere anywhere multiport dports smtp,ssmtp
Chain FORWARD (policy ACCEPT)
target prot opt source destination
Chain OUTPUT (policy ACCEPT)
target prot opt source destination
Chain fail2ban-postfix (1 references)
target prot opt source destination
DROP all -- 185.208.211.185 anywhere
RETURN all -- anywhere anywhere
Chain fail2ban-sasl (1 references)
target prot opt source destination
RETURN all -- anywhere anywhere
任何帮助都将不胜感激。谢谢。
答案1
我最终改变了failregex行postfix配置文件文件如下，现在运行良好：
failregex = (.*)warning: (.*)\[<HOST>\]: SASL (.*) authentication failed: (.*)