Explanation:
The word NOT the keyword used in the question. You need to find out the technique which preacher do not use to exploit PBX.
SYN Flood -Sends a flood of TCP/SYN packets with forged sender address, causing half-open connections and saturates available connection capacity on the target machine.
For CISA Exam you should know below mentioned techniques used by preacher for illegal purpose of PBX.
Eavesdropping on conversation, without the other parties being aware of it
Eavesdropping on conference call
Illegal forwarding calls from specific equipment to remote numbers
Forwarding a user to an unused or disabled number, thereby making it unreachable by external calls.
The following were incorrect answers:
The other options presented correctly describes the techniques used preacher for illegal purpose of PBX.
Reference:
CISA review manual 2014 Page number 357