The process of secretly capturing and analyzing network traffic is called:

The correct answer is Sniffing.

Sniffing is the process of secretly intercepting, capturing, and analyzing data packets as they travel across a network, typically using packet-sniffer software such as Wireshark or tcpdump. When the traffic is unencrypted, an attacker can read sensitive information like usernames, passwords, and messages directly from the captured packets.

Why the other options are wrong: Spoofing is impersonating a trusted identity (fake IP/MAC/email). Eavesdropping is the broad, general term for secretly listening to communication—sniffing is the specific packet-level technique used to do it. Denial of Service overwhelms a system to make it unavailable. Hence, the precise term for secretly capturing and analyzing network traffic is Sniffing.