Address Resolution Protocol (ARP) Poisoning

Address Resolution Protocol (ARP) poisoning, also known as ARP spoofing, is a network attack that involves manipulating the ARP tables on a local area network (LAN). The ARP protocol is responsible for mapping IP addresses to MAC addresses, allowing devices to communicate with each other on the network.

In an ARP poisoning attack, an attacker sends falsified ARP messages to network devices, associating their MAC address with the IP address of another legitimate device on the network. This causes the affected devices to update their ARP tables, associating the attacker's MAC address with the IP address of the legitimate device. As a result, network traffic intended for the legitimate device is redirected to the attacker's machine.

ARP poisoning attacks can be used for various malicious purposes, including:

1. Man-in-the-Middle (MitM) Attacks: By redirecting network traffic through the attacker's machine, the attacker can intercept, modify, or eavesdrop on the communication between other devices on the network. This allows the attacker to capture sensitive information such as login credentials, emails, or financial data.
2. Denial-of-Service (DoS) Attacks: In some cases, ARP poisoning attacks can be used to disrupt network connectivity by redirecting network traffic to non-existent or unreachable destinations. This can result in network congestion or a complete loss of connectivity for affected devices.

To mitigate ARP poisoning attacks and enhance network security, the following preventive measures can be implemented:

• ARP Spoofing Detection and Prevention: Deploy network monitoring tools or Intrusion Detection/Prevention Systems (IDS/IPS) that can detect and alert on ARP spoofing attempts. Implement mechanisms such as ARP inspection or dynamic ARP inspection to validate and block suspicious ARP messages.
• Static ARP Entries: Configure static ARP entries on critical devices to prevent them from accepting ARP updates from unauthorized sources. By manually specifying the MAC-IP mappings in the ARP table, the devices will not be susceptible to falsified ARP messages.
• Network Segmentation: Implement proper network segmentation using VLANs or subnets to limit the scope of ARP poisoning attacks. By separating devices into different broadcast domains, the impact of an ARP poisoning attack can be contained.
• Encryption and Secure Protocols: Use encryption protocols, such as Transport Layer Security (TLS), for securing sensitive data transmitted over the network. Employ secure communication protocols, such as HTTPS, SSH, or VPNs, to protect against eavesdropping and tampering.