Denial of service attacks are quite common. Whether it is an ICMP flood, Syn Flood, or SMURF
attack, they all are based on the concept of________.

A.
Circumventing the firewall

B.
Resource exhaustion

C.
Exploiting OS vulnerabilities

D.
Avoiding the IDS

Explanation:
Resource exhaustion is the term for the situation wherein a target system has exhausted all of its resources and can no longer respond to legitimate requests. All denial of service attacks are based on this concept.
Answer option A is incorrect. While many DoS attacks to involve circumvention the firewall, this is not a necessary component of a DoS.
Answer option D is incorrect. Avoiding IDS detection is actually very difficult for a DoS attack. Answer option C is incorrect, Many DoS attacks do depend on exploiting OS vulnerabilities, However, this is not the basic concept of a DoS.