What are the three controls may be put in place to enhance system security?

What are the three controls may be put in place to enhance system security?
Ans: The controls that you might put in place to enhance system security are:
1. Vulnerability avoidance: Controls that are intended to ensure that attacks are unsuccessful. The strategy here is to design the system so that security problems are avoided. For example, sensitive military systems are not connected to public networks so that external access is impossible. You should also think of encryption as a control based on avoidance. Any unauthorized access to encrypted data means that it cannot be read by the attacker. In practice, it is very expensive and time consuming to crack strong encryption.
2. Attack detection and neutralization: Controls that are intended to detect and repel attacks. These controls involve including functionality in a system that monitors its operation and checks for unusual patterns of activity. If these are detected, then action may be taken, such as shutting down parts of the system, restricting access to certain users, etc.
3. Exposure limitation and recovery: Controls that support recovery from problems. These can range from automated backup strategies and information ‘mirroring’ to insurance policies that cover the costs associated with a successful attack on the system.