Which of the following penetration testing techniques automatically tests every phone line in an exchange and tries to locate modems that are attached to the network?

Demon dialing, also known as war dialing, is a technique where an attacker uses a computer program to automatically dial a range of telephone numbers. The purpose is to identify which numbers answer with a modem tone, indicating a potential connection point to a network or system that could be exploited.

Sniffing involves capturing and analyzing network traffic to inspect data packets, not dialing phone lines.

Social engineering is manipulating individuals to divulge confidential information or perform actions, rather than technical scanning of phone lines.

Dumpster diving involves sifting through trash to find discarded documents or media containing sensitive information, not scanning phone lines.