主機的安全性一直是個很重要的議題, 而一般人常常會忽略掉資安的嚴重性, 又或許對於 VPS 的新手來說, 若要幫主機增加防火牆時也不知從何處著手.

我之前曾在這篇 Vesta 控制面板 中提過安裝 CSF 防火牆來防護主機安全, 但在 Vesta 預設的情況下, 是需要再自行調整設定檔內部對應的路徑之後才能 100% 發揮 CSF 的作用, 所以不建議新手在 Vesta 中使用, 因此再補充這篇安裝 fail2Ban 來防止主機被惡意入侵.

安裝及設定方式

下載 fail2ban

apt-get install fail2ban

建立設定檔

cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

編輯設定檔

nano /etc/fail2ban/jail.local

jail.local:

[DEFAULT]

# "ignoreip" can be an IP address, a CIDR mask or a DNS host
# 若要限制 IP 登入主機, 將 your-IP 置換正確 IP, 若不限制時請將其刪除
ignoreip = 127.0.0.1/8  your-IP
bantime  = 86400
maxretry = 3
.
.
.

# 設定要收到通知的電郵
destemail = your@gmail.com
.
.
.
# 這裡是設定觸發條件時的執行動作,可參考文件中的說明自訂條件
action   = %(action_mwl)s
.
.
.
# SSH 登入防護
[ssh]

enabled  = true
port     = ssh
filter   = sshd
logpath  = /var/log/auth.log
maxretry = 3
.
.
.
# SSH DDOS 防護
[ssh-ddos]

enabled  = ture
.
.
.
# FTP 登入防護
[vsftpd]

enabled  = ture

存檔後重啟 fail2ban

service fail2ban restart

在設定檔中, 凡是被[ ]框起的部份, 都是能設定防護規則的地方, 可依需求另行設定, 在這附個當有人嚐試利用 SSH 登入主機時所收到的 Eamil 通知.

以下是 fail2ban 所發出的 Email 通知範例

Hi,

The IP 94.102.63.27 has just been banned by Fail2Ban after
3 attempts against ssh.

Here are more information about 94.102.63.27:

% This is the RIPE Database query service.
% The objects are in RPSL format.
%
% The RIPE Database is subject to Terms and Conditions.
% See http://www.ripe.net/db/support/db-terms-conditions.pdf

% Note: this output has been filtered.
% To receive output for a database update, use the "-B" flag.

% Information related to '94.102.48.0 - 94.102.63.255'

% Abuse contact for '94.102.48.0 - 94.102.63.255' is 'abuse@ecatel.net'

inetnum: 94.102.48.0 - 94.102.63.255
netname: NL-ECATEL-20080829
descr: Ecatel LTD
country: NL
org: ORG-EL38-RIPE
admin-c: RvE16-RIPE
tech-c: RvE16-RIPE
status: ALLOCATED PA
mnt-by: RIPE-NCC-HM-MNT
mnt-lower: ECATEL-MNT
mnt-routes: ECATEL-MNT
source: RIPE # Filtered

organisation: ORG-EL38-RIPE
org-name: Ecatel LTD
org-type: LIR
address: Ecatel LTD
address: P.O.Box 19533
address: 2500 CM Den Haag
address: NETHERLANDS
phone: +31702204015
fax-no: +31702204015
abuse-c: AR16168-RIPE
mnt-ref: ECATEL-MNT
mnt-ref: RIPE-NCC-HM-MNT
mnt-by: RIPE-NCC-HM-MNT
admin-c: EL25-RIPE
source: RIPE # Filtered

person: Reinier van Eeden
address: Archangelkade 1-3
address: 1013 BE Amsterdam
mnt-by: IQARUS-MNT
phone: +31 64 607 11 12
nic-hdl: RvE16-RIPE
source: RIPE # Filtered

% Information related to '94.102.48.0/20AS29073'

route: 94.102.48.0/20
descr: AS29073 Route object
origin: AS29073
mnt-by: ECATEL-MNT
source: RIPE # Filtered

% This query was served by the RIPE Database Query Service version 1.75 (DB-2)

Regards,

Fail2Ban
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