6步教你封杀恶意登录服务器的ip

如何快速将恶意IP 加入防火墙黑名单

前言

经常我们的服务器在深夜，往往会遭到Nmap 扫描，然后有很多ip 试探登录连接我们的服务器，那么我们该如何面对这种情况呢？

需求描述

分析Linux系统/var/log/secure安全日志文件，将黑客或者恶意登陆次数大于20次的IP地址加入Iptables防火墙黑名单；

实验步骤

• 首先查看安全日志文件

  [root@localhost ~]# cat  /var/log/secure|more
  Jun  5 10:25:56 localhost sshd[10165]: Accepted password for root from 192.168.10.1 port 58525 ssh2
  Jun  5 10:25:56 localhost sshd[10165]: pam_unix(sshd:session): session opened for user root by (uid=
  0)
  Jun  5 10:25:59 localhost sshd[10184]: Accepted password for root from 192.168.10.1 port 58528 ssh2
  Jun  5 10:25:59 localhost sshd[10184]: pam_unix(sshd:session): session opened for user root by (uid=
  0)
  Jun  5 12:51:19 localhost sshd[10394]: Accepted password for root from 192.168.10.1 port 64063 ssh2
  Jun  5 12:51:19 localhost sshd[10394]: pam_unix(sshd:session): session opened for user root by (uid=
  0)
  Jun  5 13:03:00 localhost sshd[10428]: pam_unix(sshd:auth): authentication failure; logname= uid=0 e
  uid=0 tty=ssh ruser= rhost=192.168.10.1  user=root
  Jun  5 13:03:00 localhost sshd[10428]: pam_succeed_if(sshd:auth): requirement "uid >= 1000" not met 
  by user "root"
  Jun  5 13:03:02 localhost sshd[10428]: Failed password for root from 192.168.10.1 port 64400 ssh2
  Jun  5 13:03:06 localhost sshd[10428]: pam_succeed_if(sshd:auth): requirement "uid >= 1000" not met 
  by user "root"
  Jun  5 13:03:08 localhost sshd[10428]: Failed password for root from 192.168.10.1 port 64400 ssh2
  Jun  5 13:03:14 localhost sshd[10428]: pam_succeed_if(sshd:auth): requirement "uid >= 1000" not met 
  --More--
  

• 过滤其它ip，只看登录失败的ip地址

  [root@localhost ~]# grep "Failed password" /var/log/secure
  Jun  5 13:03:02 localhost sshd[10428]: Failed password for root from 192.168.10.1 port 64400 ssh2
  Jun  5 13:03:08 localhost sshd[10428]: Failed password for root from 192.168.10.1 port 64400 ssh2
  Jun  5 13:03:16 localhost sshd[10428]: Failed password for root from 192.168.10.1 port 64400 ssh2
  Jun  5 13:03:27 localhost sshd[10431]: Failed password for root from 192.168.10.1 port 64438 ssh2
  Jun  5 13:15:33 localhost sshd[10442]: Failed password for root from 192.168.10.10 port 49796 ssh2
  Jun  5 13:15:38 localhost sshd[10442]: Failed password for root from 192.168.10.10 port 49796 ssh2
  Jun  5 13:15:38 localhost sshd[10442]: Failed password for root from 192.168.10.10 port 49796 ssh2
  Jun  5 13:15:46 localhost sshd[10444]: Failed password for root from 192.168.10.10 port 49798 ssh2
  Jun  5 13:15:50 localhost sshd[10444]: Failed password for root from 192.168.10.10 port 49798 ssh2
  Jun  5 13:15:53 localhost sshd[10444]: Failed password for root from 192.168.10.10 port 49798 ssh2
  Jun  5 13:15:59 localhost sshd[10446]: Failed password for root from 192.168.10.10 port 49800 ssh2
  Jun  5 13:16:00 localhost sshd[10446]: Failed password for root from 192.168.10.10 port 49800 ssh2
  Jun  5 13:16:02 localhost sshd[10446]: Failed password for root from 192.168.10.10 port 49800 ssh2
  [root@localhost ~]# 
  

  ---

• 打印登录失败的ip

  [root@localhost ~]# grep "Failed password" /var/log/secure |awk '{print$(NF-3)}'
  192.168.10.1
  192.168.10.1
  192.168.10.1
  192.168.10.1
  192.168.10.10
  192.168.10.10
  192.168.10.10
  192.168.10.10
  192.168.10.10
  192.168.10.10
  192.168.10.10
  192.168.10.10
  192.168.10.10
  [root@localhost ~]# 
  

• 进行排序，统计次数

  [root@localhost ~]# grep "Failed password" /var/log/secure |awk '{print$(NF-3)}'|sort|uniq -c|sort -nr
        9 192.168.10.10
        4 192.168.10.1
  [root@localhost ~]# 
  

• 匹配恶意登录次数大于5次的ip

  [root@localhost ~]# grep "Failed password" /var/log/secure |awk '{print$(NF-3)}'|sort|uniq -c|sort -nr|awk '{if ($1>=5) print $2}'
  192.168.10.10
  [root@localhost ~]# 
  

• 对匹配出来的做一个for循环,然后写入防火墙文件

  [root@localhost ~]# for i in $(grep "Failed password" /var/log/secure|awk '{print $(NF-3)}'|sort|uniq -c|sort -nr|awk '{if($1>=5) print $2}');do sed -i "/lo/a -A INPUT -s $i -j DROP" /etc/sysconfig/iptables ;done
  

总结

运维安全在实际生产环境中有着很重要的地位，我们面对黑客疯狂扫描试探的时候，我就需要见流量封杀IP。如何快速封杀IP角色需要我们掌握数量掌握linux命令。特别是awk，sed。在我们脚本中很常用。一定要掌握好。

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