If an attacker compromised a host on a site's internal network and wanted to trick other machines into using that host as the default gateway, which type of attack would he use?

A MAC Flooding attack sends a high volume of frames with randomly spoofed source MAC addresses, exhausting the switch's content-addressable memory (CAM) table. Once the table is full, the switch enters a fail-open state and begins broadcasting all incoming frames to every port, effectively behaving like a hub; the attacker receives a copy of all segment traffic and can intercept or manipulate packets, positioning their host in the data path normally held by the default gateway.

CDP Manipulation exploits the Cisco Discovery Protocol to harvest topology information or cause device misconfigurations but does not redirect segment traffic through an attacker's host.

A Telnet Attack targets a device's management plane to gain administrative access over an unencrypted session; it does not alter network-layer path selection or default gateway assignments on other hosts.

DHCP Spoofing uses a rogue DHCP server to respond to client lease requests with an attacker-controlled default gateway address, which is a distinct and more direct technique than MAC Flooding for gateway redirection.

VLAN Hopping uses double-tagging or switch-spoofing frames to send traffic across VLAN boundaries but does not manipulate the default gateway configuration used by hosts within a segment.