Fail2Ban 简介与使用

目录

1. Fail2Ban 简介
2. Fail2Ban 安装配置与日常维护
3. Fail2Ban 目录结构
4. jail.conf 配置项说明
5. sshd.local 自定义配置项
6. mail-whois.conf 自定义动作

1. Fail2Ban 简介

Fail2Ban 是一款入侵防御软件,可以保护服务器免受暴力攻击。 它是用 Python 编程语言编写的。

Fail2Ban 基于auth 日志文件工作,默认情况下它会扫描所有 auth 日志文件,如 /var/log/auth.log、
/var/log/apache/access.log 等,并禁止带有恶意标志的IP,比如密码失败太多,寻找漏洞等等标志。

通常,Fail2Ban 用于更新防火墙规则,用于在指定的时间内拒绝 IP 地址。 它也会发送邮件通知。

Fail2Ban 为各种服务提供了许多过滤器,如 ssh、apache、nginx、squid、named、mysql、nagios 等。

Fail2Ban 能够降低错误认证尝试的速度,但是它不能消除弱认证带来的风险。

这只是服务器防止暴力攻击的安全手段之一。
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2. Fail2Ban 安装配置与日常维护

# yum install fail2ban				        ## 安装

以下配置实现:阻止 SSH 远程暴力攻击并通过 mail 通知管理员

# cat /etc/fail2ban/jail.conf				## 根据指引,修改配置应在 jail.d/ 下新建文件进行

# vim /etc/fail2ban/jail.d/sshd.local                   ## 修改配置

# cd /etc/fail2ban/jail.d
# mv 00-firewalld.conf 00-firewalld.conf.disabled       ## 禁用 firewalld,使用 iptables

# vim /etc/fail2ban/action.d/mail-whois.conf		## 定义 action

# fail2ban-client reload                                ## 让配置生效 

日常维护:

# systemctl enable fail2ban.service			## 开机启动
# systemctl start fail2ban.service			## 启动服务

# cat /var/log/fail2ban.log				## 日志文件

# fail2ban-client status				## 查看 fail2ban 的运行状态

# fail2ban-client status sshd				## 查看 jail 的详细信息,可以看到被封的 ip

# fail2ban-client set sshd unbanip 123.123.123.2 	## 解封 ip

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3. Fail2Ban 目录结构

/etc/fail2ban/

├── action.d
│   ├── dummy.conf
│   ├── hostsdeny.conf
│   ├── iptables.conf
│   ├── mail-whois.conf      ## mail 动作配置
│   ├── mail.conf
│   └── shorewall.conf
├── fail2ban.conf
├── fail2ban.local
├── filter.d
│   ├── apache-auth.conf
│   ├── apache-noscript.conf
│   ├── couriersmtp.conf
│   ├── postfix.conf
│   ├── proftpd.conf
│   ├── qmail.conf
│   ├── sasl.conf
│   ├── sshd.conf            
│   └── vsftpd.conf
├── jail.conf
|── jail.local
|—— jail.d
└── └── sshd.local          ## SSH 相关配置

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4. jail.conf 配置项说明

# cat /etc/fail2ban/jail.conf

  1 #
  2 # WARNING: heavily refactored in 0.9.0 release.  Please review and
  3 #          customize settings for your setup.
  4 #
  5 # Changes:  in most of the cases you should not modify this
  6 #           file, but provide customizations in jail.local file,
  7 #           or separate .conf files under jail.d/ directory, e.g.:
  8 #
  9 # HOW TO ACTIVATE JAILS:
 10 #
 11 # YOU SHOULD NOT MODIFY THIS FILE.
 12 #
 13 # It will probably be overwritten or improved in a distribution update.
 14 #
 15 # Provide customizations in a jail.local file or a jail.d/customisation.local.
 16 # For example to change the default bantime for all jails and to enable the
 17 # ssh-iptables jail the following (uncommented) would appear in the .local file.
 18 # See man 5 jail.conf for details.
 19 #
 20 # [DEFAULT]
 21 # bantime = 1h
 22 #
 23 # [sshd]
 24 # enabled = true
 25 #
 26 # See jail.conf(5) man page for more information

     [DEFAULT ]

     ignorecommand =					## 
     bantime = 10m					## 禁止时长,默认10分钟
     findtime = 10m					## 执行操作的窗口时长,默认10分钟
     maxretry =5					## 最大尝试次数
     backend = auto					## 指定用于获取文件修改的后端
     usedns = warn					## 
     logencoding = auto
     enabled = false					## jails 默认关闭,在自定义的 .local 中打开需要用到的项
     mode = normal					## 过滤器类型
     filter = %( name )s [mode=%(mode)s ]		## 定义过滤器
     destemail =root@localhost				## 通知将被发送到的电子邮件地址
     sender = root@					## 发件人姓名
     mta =sendmail					## 邮件传输代理(默认是 sendmail,可以改成 mail)
     protocol = tcp
     chain = <known/chain>
     port = 0:65535
     fail2ban_agent = Fail2Ban/%(fail2ban_version)s
     banaction = iptables-multiport			## 动作的捷径,用于定义动作参数
     banaction_allports = iptables-allports
     action_abuseipdb =abuseipdb
     ......
     action = %(action_)s

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5. sshd.local 自定义配置项

# vim /etc/fail2ban/jail.d/sshd.local

  3 [DEFAULT]
  4 
  5 ignoreip = 127.0.0.1/8             ## 忽略本地 IP
  6 
  7 bantime = 300                      ## IP 禁止访问时间
  8 
  9 findtime = 60                      ## 密码输入时间限制
 10 
 11 maxretry = 5                       ## 最大允许试错次数
 12 
 13 backend = auto
 14 
 15 destemail = 123456@qq.com          ## 邮件接收地址
 16 
 17 sender = 654321@163.com            ## 邮件发送地址(必需配置)
 18 
 19 mta = mail                         ## 采用 mail 邮件服务
 22 
 23 action = %(action_mw)s             ## 动作模式 action_mw
 24
 25 
 26 [sshd]
 27 
 28 enabled = true                     ## 开启 SSH 保护
 29 
 30 port = 7777                        ## SSH 端口号

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6. mail-whois.conf 自定义动作

# vim /etc/fail2ban/action.d/mail-whois.conf

  1 # Fail2Ban configuration file
  2 #
  3 # Author: xiaobo
  4 #
  5 #
  6
  7 [INCLUDES]
  8
  9 before = mail-whois-common.conf
 10
 11 [Definition]
 12
 13 # Option: actionban
 14 # Notes:  command executed when banning an IP. Take care that the 
 15 #         command is executed with Fail2Ban user rights.
 16 # Tags:   See jail.conf(5) man page
 17 # Values: CMD
 18 actionban = printf %%b "Hi:\n
 19             Subject: [Fail2Ban] <name>: banned <ip> from <fq-hostname>
 20             攻击者IP:<ip>\n
                位置:`/usr/bin/curl -s http://www.cip.cc/<ip> | sed -n 2p | awk -F ': ' '{print $2}' `\n
 21             被攻击机器名:`uname -n` \n
 22             攻击次数:<failures> 次 \n
 27             Fail2Ban提醒\n\n "|/usr/bin/mail -s "title" <dest>
 28
 29 [Init]
 30
 31 name = default
 32
 33 dest = root

参考链接 - Fail2Ban 官方用户手册
参考链接 - 5.配置 mail 邮件服务

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posted @ 2021-09-11 17:15  xiaobo0602  阅读(6507)  评论(0编辑  收藏  举报