The term System Hardening is the practice of securing a system connected to the network by reducing its attack surface. As the number of cyberattacks targeting computers and other digital systems continuously rise, it is becoming crucial for organizations to have solid system security in place. The failure to protect your systems from theft, damage, misdirection, or interruptions can affect your business and operations in negative ways. In general, organizations deploy several technical controls and processes to create a “layered defense” approach. This approach helps to limit single points of failure and exposure. However, one important process that is often overlooked is system hardening which includes making configurational changes to default system settings so that the system is more secure against information security threats. This is typically done by removing all non-essential software programs and utilities from the computer/server. While these programs may offer useful features to the user, they must be removed during system hardening if they provide "back-door" access to the system. When the system is large and used to perform multiple functions, the risk of the security breach is higher, it is advisable to implement system hardening on a small and solo-function system that is relatively more secure than a large and multi-functional one. A hardened system should serve only one purpose like a Web server or DNS or Exchange server.

Advanced system hardening may involve reformatting the hard disk and only installing the bare necessities that the server needs to function. The CD drive is listed as the first boot device, which enables the server to start from a CD or DVD if needed. File and print sharing is turned off if not necessary and TCP/IP is often the only protocol installed. The guest account is disabled, the administrator account is renamed, and secure passwords are created for all user logins. Auditing is enabled to monitor unauthorized access attempts.

• Application hardening
  

• Operating system hardening