Protecting Against Password Guessing Attacks

Overview

Kerio Connect can block IP addresses suspicious of password guessing attacks (ten unsuccessful attempts in one minute). This article covers the process of protecting Kerio Connect against them.

Step-By-Step Guide

1. Go to Configuration > Security > Security Policy tab.
2. Check the Block IP addresses suspicious of password guessing attacks option.
   
   Note: IP address is blocked for individual services. If POP3 is blocked, an attacker can attempt to log in via IMAP.
   
   
3. You can choose a group of trustworthy IP addresses.
4. To block all services, check the option Block user accounts probably targeted by password guessing to lock the affected accounts.
   
   
   
   
5. Click OK.

Confirmation: When an account is blocked, the user cannot log in.