Which of the following countermeasures is not appropriate for war dialing attacks?

A.
Monitoring and auditing for such activity.

B.
Disabling call forwarding.

C.
Making sure only necessary phone numbers are made public.

D.
Using completely different numbers for voice and data accesses.

Explanation:
War dialing, or scanning, has been a common activity in the computer underground
and computer security industry for decades. Hollywood made war dialing popular with the 1983
movie, War Games, in which a teenager searching for a videogame company ultimately uncovers
a government nuclear war warning system. The act of war dialing is extremely simple – a host
computer dials a given range of telephone numbers using a modem. Every telephone number that
answers with a modem and successfully connects to the host is stored in a log. Disabling call
forwarding is not a useful countermeasure because it’s the attacker machine the one who
connects to the attacked system and forwarding is not an issue inside the attack. Answer A, C and
D can be used as countermeasures to harder the war dial attack.