During an internal security assessment of a medium-sized enterprise network, a security analyst notices an...

CEH v13 explains that ARP poisoning (also known as ARP spoofing) occurs when an attacker sends forged ARP replies across the network to associate their MAC address with multiple IP addresses, tricking hosts into sending traffic through the attacker’s machine. This results in routing inconsistencies, intermittent connectivity, failed logins, and degraded intranet performance—exactly the symptoms described. ARP poisoning typically involves unsolicited ARP replies, which overwrite legitimate ARP cache entries. CEH emphasizes that ARP-based attacks are common on LANs because ARP lacks authentication, allowing attackers to impersonate gateways or key hosts. DHCP snooping misconfigurations (Option B) affect IP allocation, not ARP mappings. Legitimate ARP refreshes (Option C) are request-based and do not involve flooding unsolicited replies. Port security restrictions (Option D) block MAC anomalies, not create them. Therefore, ARP poisoning is the correct root cause.