記一次主機入侵攻防大戰：firewalld指定的IP段端口訪問控制

記一次主機入侵攻防大戰：firewalld指定的IP段端口訪問控制

 耕耘實錄 關注

2018.04.24 23:08 字數 622 閱讀 992評論 0喜歡 1

1、背景

一大早來公司，登陸那臺暴露在外網的服務器，登陸成功的時候，看到160000+次登陸失敗的記錄，看到這個我和個人小夥伴們都驚呆了，是誰那麼執着？小夥伴還開玩笑說是否是誰跟你有世仇啊，這麼搞你！來活了，個人服務器我作主，搞起，who怕who？

2、具體操做

一、last看一下是否有異常ip及帳戶登陸記錄.

[root@DCGH ~]# last -100
ivandu pts/0        139.130.99.123    Tue Apr 24 20:53   still logged in   
ivandu pts/0        139.129.0.194      Tue Apr 24 19:13 - 19:35  (00:21)    
ivandu pts/1        139.129.0.194      Tue Apr 24 18:02 - 19:35  (01:33)    
ivandu pts/1        139.129.0.194      Tue Apr 24 11:30 - 14:24  (02:53)    
ivandu pts/0        139.129.0.194      Tue Apr 24 11:11 - 14:24  (03:13)    
reboot   system boot  3.10.0-693.17.1. Tue Apr 24 11:10 - 21:45  (10:34)    
ivandu pts/2        139.129.0.194      Tue Apr 24 11:04 - 11:04  (00:00)    
ivandu pts/1        139.129.0.194      Tue Apr 24 10:26 - 11:10  (00:44)    
root     pts/0        139.129.0.194      Tue Apr 24 10:19 - down   (00:51)   
reboot   system boot  3.10.0-693.17.1. Tue Apr 24 10:18 - 11:10  (00:51)
.....省略一些

全是熟悉的IP，沒有異常！很好！

2.建立新用戶，用於切換到root來操做，也能夠用命令visudo給該用戶配置相關的sudo權限，本例中就直接用此帳戶su到root了(此處能夠參見我以前的加固及sodu相關的文章)。

[root@CLDevOps ~]# useradd -M ivandu
[root@CLDevOps ~]# passwd ivandu
Changing password for user ivandu.
New password: 
BAD PASSWORD: The password is shorter than 7 characters
Retype new password: 
passwd: all authentication tokens updated successfully.

3.禁止root帳戶經過ssh來遠程登陸，編輯/etc/ssh/sshd_config，禁止root用戶登陸。

[root@CLDevOps ~]# sed -i "/^PermitRootLogin/c\PermitRootLogin no" /etc/ssh/sshd_config
[root@CLDevOps ~]# systemctl restart sshd

4.退出root登陸，使用新建用戶ivandu來登陸。此處爲了再次還原當時的處置過程新建的用戶ivandu，本人一直有禁止root登陸的習慣，但願你們也養成這樣的習慣。

Could not chdir to home directory /home/ivandu: No such file or directory
-bash-4.2$ su - root
Password: 
Last login: Tue Apr 24 21:47:54 CST 2018 on pts/0
Last failed login: Tue Apr 24 22:12:33 CST 2018 from 42.7.26.88 on ssh:notty
There were 403 failed login attempts since the last successful login.

你們看一下，是否是很是瘋狂!一下子的功夫，又是幾百次登陸嘗試。

5.開始防火牆設置，添加指定網段對ssh所用的端口訪問權限。

[root@CLDevOps ~]# firewall-cmd --permanent --add-rich-rule="rule family="ipv4" source address="139.130.99.0/24" port protocol="tcp" port="22" accept"
success
[root@CLDevOps ~]# firewall-cmd --permanent --add-rich-rule="rule family="ipv4" source address="139.129.0.0/24" port protocol="tcp" port="22" accept"
success

6.移除原來firewalld中ssh相關規則，重載firewalld。

[root@CLDevOps ~]# firewall-cmd --permanent --remove-service=ssh
success
[root@CLDevOps ~]# firewall-cmd --reload
success

7.如今能夠看一下，指定網段外的ip的22端口是否同，我找了另外一臺阿里雲的機器試了一下，效果以下：

[root@heynick ~]# telnet 106.99.233.115 22
Trying 106.99.233.115...
telnet: connect to address 167.99.233.15: No route to host

8.繼續看戲，看一下日誌。

[root@CLDevOps ~]# journalctl -ex
Apr 24 22:30:29 CLDevOps sshd[20475]: Failed password for root from 42.7.26.88 port 31228 ssh2
Apr 24 22:30:30 CLDevOps unix_chkpwd[20516]: password check failed for user (root)
Apr 24 22:30:30 CLDevOps sshd[20475]: pam_succeed_if(sshd:auth): requirement "uid >= 1000" not met by user "root"
Apr 24 22:30:31 CLDevOps unix_chkpwd[20517]: password check failed for user (root)
Apr 24 22:30:31 CLDevOps sshd[20479]: pam_unix(sshd:auth): authentication failure; logname= uid=0 euid=0 tty=ssh ruser= rhost=58.218.198.159  user=root
Apr 24 22:30:31 CLDevOps sshd[20479]: pam_succeed_if(sshd:auth): requirement "uid >= 1000" not met by user "root"
Apr 24 22:30:32 CLDevOps sshd[20475]: Failed password for root from 42.7.26.88 port 31228 ssh2
Apr 24 22:30:33 CLDevOps unix_chkpwd[20518]: password check failed for user (root)
Apr 24 22:30:33 CLDevOps sshd[20475]: pam_succeed_if(sshd:auth): requirement "uid >= 1000" not met by user "root"
Apr 24 22:30:33 CLDevOps sshd[20479]: Failed password for root from 58.218.198.159 port 26800 ssh2
Apr 24 22:30:35 CLDevOps sshd[20475]: Failed password for root from 42.7.26.88 port 31228 ssh2
Apr 24 22:30:35 CLDevOps sshd[20475]: error: maximum authentication attempts exceeded for root from 42.7.26.88 port 31228 ssh2 [preauth]
Apr 24 22:30:35 CLDevOps sshd[20475]: Disconnecting: Too many authentication failures [preauth]
Apr 24 22:30:35 CLDevOps sshd[20475]: PAM 5 more authentication failures; logname= uid=0 euid=0 tty=ssh ruser= rhost=42.7.26.88  user=root
Apr 24 22:30:35 CLDevOps sshd[20475]: PAM service(sshd) ignoring max retries; 6 > 3
Apr 24 22:30:38 CLDevOps sshd[20479]: Received disconnect from 58.218.198.159 port 26800:11:  [preauth]
Apr 24 22:30:38 CLDevOps sshd[20479]: Disconnected from 58.218.198.159 port 26800 [preauth]

依然仍是辣麼瘋狂！變着ip來搞我呢！早上還換着用戶呢!哈哈！

固然我這臺機器上的服務監聽的其餘端口我也是開放着的，那些就不必怕了，遇到狀況另當別論。

9.若是別人只用固定ip來攻擊咱，咱們單獨封鎖那個ip就行啦，命令這樣的，下面咱們來試一下封鎖ip：58.218.198.159

[root@CLDevOps ~]# firewall-cmd --permanent --add-rich-rule="rule family="ipv4" source address="58.218.198.159" port protocol="tcp" port="22" drop"
success
[root@CLDevOps ~]# firewall-cmd --reload
success
[root@CLDevOps ~]# firewall-cmd --list-rich-rule
rule family="ipv4" source address="139.130.99.0/24" port port="22" protocol="tcp" accept
rule family="ipv4" source address="139.129.0.0/24" port port="22" protocol="tcp" accept
rule family="ipv4" source address="58.218.198.159" port port="22" protocol="tcp" drop

3、總結

1.要養成良好的習慣，不要幹啥只會用root！

2.設置一個複雜度比較高的密碼。

3.安全加固頗有必要。

小禮