Q: In a corporate network, an attacker executes a malicious script that generates millions of random fake MAC addresses and rapidly fills up the network switch's CAM table (MAC address table). What happens to the switch, and what security risk does this open?

This is a MAC Flooding attack. A switch has a limited amount of memory to map MAC addresses to physical ports. When the attacker's script completely exhausts this memory, the switch can no longer remember where legitimate devices are plugged in. When a switch doesn't know where to send a packet, its default fail-safe protocol is to "fail-open" and act like a Hub. It broadcasts every single incoming packet out of *every single port* on the switch. The security risk is catastrophic: the attacker can now run a packet sniffer (like Wireshark) on their laptop and passively see all horizontal traffic intended for other computers, intercepting plaintext passwords and sessions. (Mitigated by configuring Switch Port Security algorithms limiting MACs per physical port).