Address Resolution Protocol (ARP) spoofing, also known as ARP poisoning or ARP cache poisoning, is a type of cyberattack in which an attacker manipulates the ARP table of a network to redirect traffic intended for one network node (such as a computer or router) to another node controlled by the attacker. This can lead to various security breaches, such as interception of data or unauthorized access to network resources.

Here’s how ARP spoofing works and its key aspects:

1. ARP Protocol: ARP is a network protocol used to map IP addresses to MAC addresses within a local network. It ensures that devices can communicate with each other on a LAN by resolving IP addresses to MAC addresses.
2. Attack Process:
   • In a typical network communication, devices use ARP to determine the MAC address corresponding to an IP address by broadcasting an ARP request to the network.
   • The device with the IP address in question responds with its MAC address.
   • An attacker engaged in ARP spoofing sends fake ARP responses to the network, claiming to have the correct IP-to-MAC mapping for a target IP address.
   • The attacker’s fake ARP responses can overwrite legitimate ARP cache entries on other devices, causing them to send data to the attacker’s MAC address instead of the intended destination.
3. Goals and Motivations:
   • Intercepting Data: By redirecting traffic through their system, attackers can intercept and analyze the data passing through the network.
   • Man-in-the-Middle Attacks: ARP spoofing is often used in man-in-the-middle attacks, where attackers intercept and potentially modify data between two communicating parties.
   • Eavesdropping: Attackers can use ARP spoofing to eavesdrop on network conversations.
4. Effects of ARP Spoofing:
   • Data Interception: Attackers can capture sensitive information, such as usernames, passwords, and confidential data, passing through the network.
   • Network Disruption: Incorrect ARP cache entries can lead to network connectivity issues and performance degradation.
5. Countermeasures:
   • ARP Inspection: Some network devices and switches support ARP inspection, which monitors and validates ARP traffic to prevent spoofing.
   • Static ARP Entries: Manually configuring static ARP entries on devices can help prevent dynamic ARP cache poisoning.
   • Network Segmentation: Segmenting the network into smaller subnets can limit the scope of ARP spoofing attacks.
   • Intrusion Detection Systems (IDS) and Intrusion Prevention Systems (IPS): These systems can detect and mitigate ARP spoofing attempts.
6. Detection and Prevention: ARP spoofing attacks can be detected through network monitoring and analysis tools. Implementing security mechanisms such as ARP inspection and monitoring for unusual traffic patterns can help prevent successful ARP spoofing attacks.

ARP spoofing attacks are a significant security concern, especially in unsecured or poorly configured networks. Implementing strong network security practices, monitoring network traffic, and using security tools can help mitigate the risks associated with ARP spoofing.