A security analyst is investigating a call from a user regarding one of the websites receiving a 503: Service unavailable error. The analyst runs a netstat -an command to discover if the webserver is up and listening. The analyst receives the following output:
TCP 10.1.5.2:80 192.168.2.112:60973 TIME_WAIT
TCP 10.1.5.2:80 192.168.2.112:60974 TIME_WAIT
TCP 10.1.5.2:80 192.168.2.112:60975 TIME_WAIT
TCP 10.1.5.2:80 192.168.2.112:60976 TIME_WAIT
TCP 10.1.5.2:80 192.168.2.112:60977 TIME_WAIT
TCP 10.1.5.2:80 192.168.2.112:60978 TIME_WAIT
Which of the following types of attack is the analyst seeing?
A. Buffer overflow
B. Domain hijacking
C. Denial of service
D. Arp poisoning

Denial of service error occurs when the legitimate users are unable to access the system. They are then unable to access the information contained in the system. This can also be a cyber attack on the system in which user are stopped from accessing their personal and important information and then ransom is claimed to retrieve the attack. In such case system resources and information are temporarily unavailable to the users which disrupts the services.