Fail2ban

With fail2ban you can enhance the security of Group-Office. When a user logs in Group-Office writes log message to /home/groupoffice/log/info.log (or wherever your file_storage_path is). fail2ban analyzes this file and when someone enters a number of wrong passwords it will block the IP address using IPtables.

To install fail2ban on debian enter:

apt-get install fail2ban

Create the Group-Office script /etc/fail2ban/filter.d/groupoffice.conf:

# Fail2Ban configuration file
#
#   Group-Office
#

[Definition]

failregex = .*LOGIN FAILED for user: .* from IP: <HOST>

ignoreregex = 

Edit jail.conf and add:

[groupoffice]

enabled = true
port	= http,https
filter	= groupoffice
logpath = /home/groupoffice/log/info.log
maxretry = 3

Edit the Group-Office config.php file and add:

$config['info_log']='/home/groupoffice/log/info.log';

Mail server

If you use the Group-Office mailserver it's also recommended to enable sasl, dovecot and postfix filters.