Which of the following is an example of the defense in-depth security principle?
A.
Using two firewalls of different vendors to consecutively check the incoming network traffic
B.
Using a firewall as well as logical access controls on the hosts to control incoming network traffic
C.
Having no physical signs on the outside of a computer center building
D.
Using two firewalls in parallel to check different types of incoming traffic
Explanation:
Defense in-depth means using different security mechanisms that back each other up. When network traffic passes the firewall unintentionally, the logical access controls form a second line of defense. Using two firewalls of different vendors to consecutively check the incoming network traffic is an example of diversity in defense. The firewalls are the same security mechanisms. By using two different products the probability of both products having the same vulnerabilities is diminished. Havingno physical signs on the outside of a computer center building is a single security measure. Using two firewalls in parallel to check different types of incoming traffic is a single security mechanism and therefore no different than having a single firewall checking all traffic.