Intrusion Detection System.

https://en.wikipedia.org/wiki/Intrusion_detection_system

Antivirus software

https://en.wikipedia.org/wiki/Antivirus_software

"Rkhunter Ubuntu" by Michael Boelen et al - Screenshot taken in Ubuntu. Via Wikipedia - https://en.wikipedia.org/wiki/File:Rkhunter_Ubuntu.png#/media/File:Rkhunter_Ubuntu.png

Firewall (computing)

https://en.wikipedia.org/wiki/Firewall_(computing)

Information security

https://en.wikipedia.org/wiki/Information_security