1.3.2 Defenses

Defense strategies combine proactive and reactive security measures. There are six primary approaches to securing a system (Pfleeger et al. 2015):

Proactive approaches:

1. Preventive controls: Ensure that attacks are impossible or unsuccessful (e.g., firewalls, vulnerability patches).
   
2. Deterrence controls: Make attacks more challenging for adversaries (e.g., two-f...