An attack used to find unencrypted information in network traffic is called:

WEP cracking specifically targets the Wired Equivalent Privacy encryption algorithm used in older Wi-Fi networks to recover the encryption key, not to generically read unencrypted traffic.

Packet sniffing uses a network interface in promiscuous mode and a capture tool (such as Wireshark) to intercept all frames on a network segment. Unencrypted protocols like HTTP, FTP, and Telnet expose plaintext data that is directly readable in captured packets. This makes packet sniffing a primary passive reconnaissance technique for harvesting credentials or sensitive data.

A ping sweep sends ICMP echo requests to a range of IP addresses to discover which hosts are live, and does not capture or read payload data.

Social engineering manipulates people through deception to voluntarily disclose information and does not involve intercepting network traffic.