Install and Configure Fail2Ban for Zimbra on CentOS 7

Below is how to install and configure Fail2Ban for Zimbra. In this guidance, I use CentOS. Please adjust python-pip version if using another OS

1. Install pip

yum install python3-pip

2. Install dependencies required by Fail2Ban

pip3 install pyinotify
pip3 install dnspython

3. Download and extract Fail2Ban

cd /tmp/
wget -c https://github.com/fail2ban/fail2ban/archive/0.9.4.tar.gz

4. Install Fail2Ban

tar -xvf 0.9.4.tar.gz
cd fail2ban-0.9.4
python3 setup.py install

5. Copy Fail2Ban service to systemd

cp files/fail2ban.service /usr/lib/systemd/system/

6. Adjust bin location on Fail2Ban service

vi /usr/lib/systemd/system/fail2ban.service

Adjust the following lines. Change /usr/bin become /usr/local/bin

ExecStart=/usr/local/bin/fail2ban-client -x start
ExecStop=/usr/local/bin/fail2ban-client stop
ExecReload=/usr/local/bin/fail2ban-client reload

Create fail2ban folder

mkdir /var/run/fail2ban
vi /usr/lib/tmpfiles.d/var.conf

Add this line at the bottom

d /var/run/fail2ban 0755 - - -

Reload systemd

systemctl daemon-reload

7. Create zimbra.jail

vi /etc/fail2ban/jail.d/zimbra.local

Fill with the following lines and save

[zimbra-submission]
enabled = true
filter = zimbra-submission
logpath = /var/log/zimbra.log
maxretry = 3
findtime = 3600
bantime = 36000
action = iptables-multiport[name=zimbra-submission, port="25,465,587", protocol=tcp]

[zimbra-webmail]
enabled = true
filter = zimbra-webmail
logpath = /opt/zimbra/log/mailbox.log
maxretry = 3
findtime = 3600
bantime = 36000
action = iptables-multiport[name=zimbra-webmail, port="80,443", protocol=tcp]

[zimbra-admin]
enabled = true
filter = zimbra-admin
logpath = /opt/zimbra/log/mailbox.log
maxretry = 3
findtime = 3600
bantime = 36000
action = iptables-multiport[name=zimbra-admin, port="7071", protocol=tcp]

8. Create filters

– Zimbra Admin

curl -k https://raw.githubusercontent.com/imanudin11/zimbra-fail2ban/master/zimbra-admin.conf > /etc/fail2ban/filter.d/zimbra-admin.conf

– Zimbra Webmail

curl -k https://raw.githubusercontent.com/imanudin11/zimbra-fail2ban/master/zimbra-webmail.conf > /etc/fail2ban/filter.d/zimbra-webmail.conf

– Zimbra SMTP/SMTPS/Submission

curl -k https://raw.githubusercontent.com/imanudin11/zimbra-fail2ban/master/zimbra-submission.conf > /etc/fail2ban/filter.d/zimbra-submission.conf

9. Ignore localhost and Zimbra IP

Open file /etc/fail2ban/jail.conf. Find line “ignoreip =” and add the IP address that will be ignored from Fail2Ban checking. You can use comma or space to add multiple IP

ignoreip = 127.0.0.1/8 IP-ADDRESS-OF-ZIMBRA/32 OTHER-IP-ADDRESS/32

10. Enable and restart Fail2Ban

systemctl enable fail2ban
systemctl restart fail2ban

Additional Configuration :

– Block type that uses by Fail2Ban is “REJECT –reject-with icmp-port-unreachable”. If you want to use DROP, open file /etc/fail2ban/action.d/iptables-common.conf and change it to blocktype = DROP

11. Logging the Originating IP

In a multi-server environment, or any environment running a proxy, the mailboxd server may only log the IP of the connecting proxy. X-Originating-IP support for nginx or other fronting proxy. In order to use this feature, you must define the Trusted IPs of your internal nginx proxies, so that the mailstores will instead capture the data on the originating IP from the HTTP traffic. By default, the zimbraMailTrustedIP is empty.

Run the following command to configure zimbraMailTrustedIP

zmprov mcf +zimbraMailTrustedIP {IP of nginx-1} +zimbraMailTrustedIP {IP of nginx-2}

Example

zmprov mcf +zimbraMailTrustedIP 127.0.0.1 +zimbraMailTrustedIP 10.11.12.13

Check the configuration then restart the mailbox

zmprov gcf zimbraMailTrustedIP
zmmailboxdctl restart

12. Test regex

You can test regex with run this command

fail2ban-regex /opt/zimbra/log/mailbox.log /etc/fail2ban/filter.d/zimbra-webmail.conf

Now my Zimbra already use Fail2Ban. If you want to see ip address that blocked by Fail2Ban, run fail2ban-client command

fail2ban-client status

If you want to see zimbra-webmail jail, run command

fail2ban-client status zimbra-webmail

[root@mail ~]# fail2ban-client status zimbra-webmail
Status for the jail: zimbra-webmail
|- Filter
| |- Currently failed: 1
| |- Total failed: 11
| `- File list: /opt/zimbra/log/mailbox.log
`- Actions
|- Currently banned: 1
|- Total banned: 1
`- Banned IP list: 123.xx.xx.xx

Src:

How to Install and Configure Fail2Ban for Zimbra