如何快速將惡意IP 加入防火墻黑名單

前言

經常我們的服務器在深夜，往往會遭到Nmap 掃描，然后有很多ip 試探登錄連接我們的服務器，那么我們該如何面對這種情況呢？

需求描述

分析Linux系統/var/log/secure安全日志檔案，將黑客或者惡意登陸次數大于20次的IP地址加入Iptables防火墻黑名單；

實驗步驟

• 首先查看安全日志檔案

  [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--
  

• 過濾其它ip，只看登錄失敗的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 ~]# 
  

  ---

• 列印登錄失敗的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 ~]# 
  

• 進行排序，統計次數

  [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 ~]# 
  

• 匹配惡意登錄次數大于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 ~]# 
  

• 對匹配出來的做一個for回圈,然后寫入防火墻檔案

  [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
  

總結

運維安全在實際生產環境中有著很重要的地位，我們面對黑客瘋狂掃描試探的時候，我就需要見流量封殺IP，如何快速封殺IP角色需要我們掌握數量掌握linux命令，特別是awk，sed，在我們腳本中很常用，一定要掌握好，

創作不易，點個贊，留個愛心吧