Helga is a systems administrator. She sees that an attacker from a remote location is sending invalid packets, trying to monopolize Helga’s network connection so that a denial of service occurs. What characteristic of the activity makes Helga think this is a denial-of-service attack?

A.
Bandwidth consumption

B.
Hijacking of internal user resources

C.
Use of an illicit server

D.
System slowdown

Explanation:
Bandwidth consumption is a technique for denial of service, and Helga would see her connection slowing down very fast.
Incorrect Answers:
B: Hijacking would not be used in a DoS attack.
C: The illicit server attack is not a technique that would be used for DoS attack.
D: Since a denial of service (DoS) attack is normally used to consume network resources to the point of making a system inaccessible, you would not see a system slowdown. The system may be able to fight off the network traffic without committing system resources so everything may look fine.