During a stealth assessment, an attacker exploits intermittent delays in ARP responses from a target...

CEH teaches that ARP-based attacks vary in sophistication from basic poisoning to more specialized techniques such as switch port stealing. In environments where ARP poisoning defenses or inspection tools limit traditional attacks, attackers may exploit timing vulnerabilities in ARP reply behavior. Switch port stealing works by sending spoofed ARP replies at precisely the right moment—before the legitimate ARP response from the target host—causing the switch’s CAM table to update temporarily and associate the target’s IP address with the attacker’s MAC address. CEH emphasizes that switches trust the latest ARP update, so even brief timing windows enable partial packet interception. This is different from fully persistent ARP poisoning, which continuously overwrites ARP tables, and from passive sniffing, which cannot capture unicast traffic on a switched network. This attack is particularly useful when ARP spoofing is mitigated because it relies on opportunistic timing rather than full table poisoning. The intermittent nature of intercepted packets matches CEH’s description of switch port stealing behavior.