When a CentOS server has been successfully installed it is important to be able to make it more secure. This server hardening objective can be achieved through some simple steps. When you can implement server hardening you can be sure that there is limited usage of this server as there are many authentication criteria and authorization systems. While you may add many security features to the new CentOS server to achieve this purpose, there are three basic steps which are considered to be most useful.
Some of the commonly used measures are creating maximum password login-attempts for every session, enabling audit services, installing advanced intrusion detection mechanisms, limiting password reuse, removing idle users and setting denial for multiple failed password attempts.
For every session, for instance, there should be a definite password login attempt. By doing this you can ensure that there are no unauthorized users trying to launch a brute force hit on your server. Usually, users are limited to three login attempts. When you use CentOS, you may make use of the command cd/etc/pam.d. Using the vi editor, you may open the system-auth files and edit the pam_pwquality.so. This allows you to change the number of login attempts to three or even lower. You can then save this file to complete configuring this max password login attempt feature. Following this, you may install the AIDE or Advanced Intrusion Detection Environment. This is designed to take snapshots of the system, register hashes, modification times and various data related to files which are defined by administrators. The snapshot is then used to create a database for checking and verifying file integrity. There are sophisticated methods for evaluating and reporting malicious changes within this server. For doing this installation in CentOS, you must use command yum install aide. When an installation is done, you may check the AIDE version. You have to then create a database and you may use default files for this. The command aide-init is used for generating databases. Finally, the third popular step is by enabling an audit service. The Auditd is part of the Linux Auditing Systems and can write audit records. So, you get to configure audit rules, and view logs, customizing these based on your needs. This Auditd will offer useful insights into how the server performs and lets you monitor its activities.