Q148. The helpdesk is receiving multiple calls about slow and intermittent Internet access from the finance department. The following information is compiled:
Caller 1, IP 172.16.35.217, NETMASK 255.255.254.0
Caller 2, IP 172.16.35.53, NETMASK 255.255.254.0
Caller 3, IP 172.16.35.173, NETMASK 255.255.254.0
All callers are connected to the same switch and are routed by a router with five built-in interfaces. The upstream router interface’s MAC is 00-01-42-32-ab-1a A packet capture shows the following:
09:05:15.934840 arp reply 172.16.34.1 is-at 00:01:42:32:ab:1a
(00:01:42:32:ab:1a)
09:06:16.124850 arp reply 172.16.34.1 is-at 00:01:42:32:ab:1a
(00:01:42:32:ab:1a)
09:07:25.439811 arp reply 172.16.34.1 is-at 00:01:42:32:ab:1a
(00:01:42:32:ab:1a)
09:08:10.937590 IP 172.16.35.1 > 172.16.35.255: ICMP echo request, id
2305, seq 1, length 65534
09:08:10.937591 IP 172.16.35.1 > 172.16.35.255: ICMP echo request, id
2306, seq 2, length 65534
09:08:10.937592 IP 172.16.35.1 > 172.16.35.255: ICMP echo request, id
2307, seq 3, length 65534
Which of the following is occurring on the network?
The above packet capture shows an attack where the attacker is busy consuming your resources (in this case the router) and preventing normal use. This is thus a Denial Of Service Attack.