我的 Debian 服务器最近遭受了攻击，我一直在仔细查看日志，看看我能做些什么来加固它。我已经运行 fail2ban 一段时间了，但我注意到 apache-noscript jail 似乎不起作用。fail2ban 包最近已更新，这个特定 jail 的内容已更改，但我不知道它以前是否曾经工作过。这是现在的 jail：
# Fail2Ban configuration file
#
# Author: Cyril Jaquier
#
# $Revision: 728 $
#
[INCLUDES]
# Read common prefixes. If any customizations available -- read them from
# common.local
before = apache-common.conf
[Definition]
# Option: failregex
# Notes.: regex to match the password failure 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 = ^%(_apache_error_client)s (File does not exist|script not found or unable to stat): /\S*(\.php|\.asp|\.exe|\.pl)\s*$
^%(_apache_error_client)s script '/\S*(\.php|\.asp|\.exe|\.pl)\S*' not found or unable to stat\s*$
# Option: ignoreregex
# Notes.: regex to ignore. If this regex matches, the line is ignored.
# Values: TEXT
#
ignoreregex =
它现在指的是 apache-common.conf，如下所示：
# Generic configuration items (to be used as interpolations) in other
# apache filters
#
# Author: Yaroslav Halchenko
#
#
[INCLUDES]
# Load customizations if any available
after = apache-common.local
[DEFAULT]
# Common prefix for [error] apache messages which also would include <HOST>
_apache_error_client = \[[^]]+\] \[error\] \[client <HOST>\]
这是我的jail.local：
# Fail2Ban configuration file
#
# Author: Cyril Jaquier
#
# $Revision: 728 $
#
[INCLUDES]
# Read common prefixes. If any customizations available -- read them from
# common.local
before = apache-common.conf
[Definition]
# Option: failregex
# Notes.: regex to match the password failure 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 = ^%(_apache_error_client)s (File does not exist|script not found or unable to stat): /\S*(\.php|\.asp|\.exe|\.pl)\s*$
^%(_apache_error_client)s script '/\S*(\.php|\.asp|\.exe|\.pl)\S*' not found or unable to stat\s*$
# Option: ignoreregex
# Notes.: regex to ignore. If this regex matches, the line is ignored.
# Values: TEXT
#
ignoreregex =
root@serverb3:/etc/fail2ban/filter.d# cat ../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.
#
# 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]>
#
# $Revision$
#
# 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
ignoreip = 127.0.0.1/8 62.84.178.107 217.204.106.228 192.168.10.0/24 192.168.0.1
#ignoreip = 127.0.0.1/8
bantime = 600
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 = 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 overridden 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
# 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"]
# 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"]
# 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 = 666
filter = sshd
logpath = /var/log/auth.log
[dropbear]
enabled = false
port = ssh
filter = sshd
logpath = /var/log/dropbear
maxretry = 6
# Generic filter for pam. Has to be used with action which bans all ports
# such as iptables-allports, shorewall
[pam-generic]
enabled = true
# 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
[xinetd-fail]
enabled = true
filter = xinetd-fail
port = all
banaction = iptables-multiport-log
logpath = /var/log/daemon.log
maxretry = 2
[ssh-ddos]
enabled = true
port = 666
filter = sshd-ddos
logpath = /var/log/auth.log
#
# HTTP servers
#
[apache]
enabled = true
port = http,https
filter = apache-auth
logpath = /var/log/apache*/*error.log
# 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 = true
port = http,https
filter = apache-noscript
logpath = /var/log/apache*/*error.log
maxretry = 0
bantime = 2419200
[apache-overflows]
enabled = true
port = http,https
filter = apache-overflows
logpath = /var/log/apache*/*error.log
maxretry = 2
[apache-nohome]
enabled = true
port = http,https
filter = apache-nohome
logpath = /var/log/apache*/*error.log
findtime = 600
[apache-404]
enabled = true
port = http,https
filter = apache-404
logpath = /var/log/apache*/*access.log
findtime = 600
maxretry = 5
bantime = 86400
[apache-400]
enabled = true
port = http,https
filter = apache-400
logpath = /var/log/apache*/*.log
maxretry = 0
bantime = 2419200
[web-admin]
enabled = true
port = http,https
filter = web-admin
logpath = /var/log/auth.log
[apache-w00t]
enabled = true
port = http,https
filter = apache-w00t
logpath = /var/log/apache*/*access.log
maxretry = 0
bantime = 2419200
[apache-vtigercrm]
enabled = true
port = http,https
filter = apache-vtigercrm
logpath = /var/log/apache*/*access.log
maxretry = 0
bantime = 2419200
[apache-vicidial]
enabled = true
port = http,https
filter = apache-vicidial
logpath = /var/log/apache*/*access.log
maxretry = 0
bantime = 2419200
[apache-phpmyadmin]
enabled = true
port = http,https
filter = apache-phpmyadmin
logpath = /var/log/apache*/*access.log
maxretry = 0
bantime = 2419200
#
# 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 = true
port = ftp,ftp-data,ftps,ftps-data
filter = proftpd
logpath = /var/log/proftpd/proftpd.log
[pure-ftpd]
enabled = false
port = ftp,ftp-data,ftps,ftps-data
filter = pure-ftpd
logpath = /var/log/auth.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 = true
port = smtp,ssmtp
filter = postfix
logpath = /var/log/mail.log
maxretry = 5
bantime = 86400
[couriersmtp]
enabled = false
port = smtp,ssmtp
filter = couriersmtp
logpath = /var/log/mail.log
[roundcube]
enabled = true
port = http,https
filter = roundcube
logpath = /home/web/roundcube*/logs/errors
findtime = 600
#
# 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
maxretry = 6
# 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 = true
port = smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
filter = dovecot
logpath = /var/log/mail.log
findtime = 600
# 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
据我所知，所有其他监狱都正常运转。
如果我运行fail2ban-regex "/var/log/apache2/error.log" /etc/fail2ban/filter.d/apache-noscript.conf它，它会得到两次命中。它找到的其中一个 IP 地址被禁止，因为它还触发了另一个 jail，但另一个 IP 地址根本没有被禁止（即在 fail2ban 日志中搜索“noscript”不会得到任何命中，在“iptables -L -n”中也不会得到任何结果）。以下是来自 apache error.log 的相关条目：
[2013 年 11 月 13 日星期三 02:11:06] [错误] [客户端 91.226.212.41] 脚本“/home/web/remote.php”未找到或无法启动
[2013 年 11 月 15 日星期五 00:20:34] [错误] [客户端 85.114.135.126] 脚本“/home/web/wp-login.php”未找到或无法启动
在我看来，这两个条目都应该触发 jail。有什么想法为什么没有触发吗？
短暂性脑缺血。
答案1
我知道这是一个老话题，但仍然在谷歌上搜索这个主题。在将 Debian 升级到 Stretch（并将 Apache 升级到 2.4.25）后，我遇到了一个非常类似的问题
Fail2Ban 运行正常，但一些与 Apache 相关的 jail 与其过滤器的正则表达式模式不匹配。经过几个小时的反复试验，我发现 fail2ban 使用标签来识别远程主机，但它只替换了 IP 地址/主机名，而且由于较新的 Apache 日志是在主机 IP 后添加端口创建的，因此它不会匹配。
因此 fail2ban 的 apache-noscript.conf 中的原始正则表达式行：
[[]client <HOST>[]] script '/\S*(\.php|\.asp|\.exe|\.pl)\S*' not found or unable to stat*$
与错误日志中的相应行不匹配，例如：
[client 213.97.42.29:50067] script '/home/www/vhost/webroot/wp-login.php' not found or unable to stat
将可选的 :port 模式添加到正则表达式后，它就可以很好地工作了。
请注意，标签位于可选端口号正则表达式模式之前，因此必须将其添加在和以下 [ 字符之间，如下所示：
<HOST>(:\d{1,5})?
经过修改后，同一行内容如下所示：
[[]client <HOST>(:\d{1,5})?[]] script '/\S*(\.php|\.asp|\.exe|\.pl)\S*' not found or unable to stat*$
我希望它将来能够对某些人有所帮助。
答案2
我也注意到apache-noscript.conf无法script not found or unable to stat: /usr/lib/cgi-bin/php在我的 debian wheezy 笔记本电脑服务器上的 /var/log/apache2/error.log 中捕获类似条目及其变体。
[Fri Dec 20 20:09:34 2013] [error] [client 89.248.160.192] script not found or unable to stat: /usr/lib/cgi-bin/php
[Fri Dec 20 20:09:34 2013] [error] [client 89.248.160.192] script not found or unable to stat: /usr/lib/cgi-bin/php4
[Fri Dec 20 20:09:35 2013] [error] [client 89.248.160.192] script not found or unable to stat: /usr/lib/cgi-bin/php5
[Fri Dec 20 20:09:35 2013] [error] [client 89.248.160.192] script not found or unable to stat: /usr/lib/cgi-bin/php-cgi
[Fri Dec 20 20:09:36 2013] [error] [client 89.248.160.192] script not found or unable to stat: /usr/lib/cgi-bin/php.cgi
仔细检查过滤器 /etc/fail2ban/filter.d/apache-noscript.conf 后，我意识到缺少php并且其变体在 failregex 表达式中没有前导句点，这是导致过滤器失败的原因。
通过添加 \php|\php4|\php5|\php-cgi|\php.cgi 修改 failregex 表达式后，如下所示，
failregex = ^%(_apache_error_client)s (File does not exist|script not found or unable to stat: /\S*(\php|\php4|\php5|\php-cgi|\php.cgi|\.php|\.asp|\.exe|\.pl)\s*$
并通过运行测试过滤器
fail2ban-regex "/var/log/apache2/error.log" /etc/fail2ban/filter.d/apache-noscript.conf
过滤器捕获了所有script not found or unable to stat: /usr/lib/cgi-bin/php条目及其变体！问题已解决。希望这对其他人有所帮助。
答案3
这个问题在 Fail2Ban 的新版本中已经修复。我刚刚在 Apache v2.4.41 和 Fail2Ban v0.11.1-1 上安装了它，它正确地看到了我对 /fakefile.html 等的点击。
答案4
奇怪的是，昨天我的 apache error.log 中的以下行触发了监禁：
[Tue Nov 26 02:17:58 2013] [error] [client 193.17.208.73] script '/home/web/admin.php' not found or unable to stat
所以我猜它起作用了。很奇怪。