Definition:
ARP spoofing is an attack where the attacker sends fake ARP messages to associate their MAC address with the IP of another device (like a gateway).

Goal:
Intercept, modify, or block traffic (i.e., Man-in-the-Middle attack).

How it works:

  • ARP is a protocol that maps IP addresses to MAC addresses.

  • The attacker sends forged ARP replies to the victim and the gateway.

  • Both end up sending data to the attacker.

Impact:

  • Intercept sensitive data.

  • Denial of service.

  • Session hijacking.

Tools: Cain & Abel, Ettercap, arpspoof

Prevention:

  • Use static ARP entries.

  • Implement ARP inspection (e.g., Dynamic ARP Inspection on switches).

  • Use encrypted protocols (SSH, HTTPS).