What is a NULL scan attack and how can you minimize its effects?

What is a NULL scan attack and how can you minimize its effects?

A.
A NULL scan attack consists of a series of packets that have source port 0 and various destination ports set. This attack can be minimized using 3et security screen ids-option my screen tcp-no-null and udp-no-null.

B.
A NULL scan attack is an attack targeting port 0 of the remote device’s TCP/IP stack. This attack can be minimized Using set security idp sensor-configuration flow no-allow-tcp without-flow.

C.
A NULL scan attack uses TCP packets with no flags set. This attack can be minimized using set screen ids-option my-screen tcp tcp-no-flag.

D.
A NULL attack makes use of UDP packets that contain only null characters in their payload.
This attack can be minimized using a stateless firewall filter.