What is ARP Poisoning Attack? What can be done to prevent?

Having a single network of defenses does not guarantee complete security as hackers keep coming up with new ways to get around. They understand that launching attacks directly is no longer effective because advanced security mechanisms can easily detect them. Hiding behind legitimate networks through techniques like ARP Poisoning makes their job easier.

With ARP Poisoning, cybercriminals can redirect your IP address and intercept your communications in transit without your knowledge. Here's how this attack method works and how you can prevent it.

What is ARP Poisoning Attack?

Address Resolution Protocol (ARP) is a connection process that binds an IP address to the static physical address of a Media Access Control (MAC) over a local area network (LAN). Since IP and MAC addresses have different components, they are not compatible. ARP reconciles this difference to ensure that both elements are in sync. Otherwise, they won't recognize each other.

ARP Poisoning attack is a process whereby an intruder sends malicious content over a local area network (LAN) to redirect the connection of a legitimate IP address to their MAC address. In this process, an attacker who replaces the original MAC address will connect to the IP address, allowing them to access the messages people send to the authentic MAC address.

How does ARP Poisoning attack work?

What is ARP Poisoning Attack? What can be done to prevent? Picture 1

Several networks can operate on a local area network (LAN) at the same time. Each active network has a specific IP address that serves as a means of identifying and distinguishing it from other networks. As data from different networks arrives at the gateway, ARP arranges them accordingly, so each network goes straight to the intended destination.

The attacker generates and sends a false ARP message to the configured system. They add their own MAC address and the target's IP address in the message. When receiving and processing the wrong ARP message, the system will synchronize the attacker's MAC address with the IP address.

When the LAN connects the IP address to the intruder's MAC address, the intruder starts receiving all the messages intended for the legitimate MAC address. They can eavesdrop on communications to retrieve sensitive data in exchange, modify communications by inserting malicious content, or even delete data during transmission so that the recipient does not receive it.

Types of ARP Poisoning Attacks

Cybercriminals can launch ARP attacks in two ways: Forgery and cache poisoning.

ARP spoofing

ARP spoofing is a process in which a threat actor spoofs and sends an ARP response to the system they are targeting. A fake reply is all the intruder has to send to the system in question in order to whitelist its MAC address. This makes ARP spoofing easy.

Attackers also use ARP spoofing to perform other types of attacks, such as session hijacking, where they take over your browsing sessions, and Man-in-the-Middle attacks, where they intercept communication between two devices connected to a network.

ARP cache poisoning

Contamination in this type of ARP attack originates from the attacker generating and sending multiple spoofed ARP responses to their target system. They do this to the point of flooding the system with invalid entries and failing to identify its legitimate networks.

Traffic turbulence techniques seize the opportunity to redirect IP addresses to their own systems and block communications passing through them. Threat actors use this ARP attack to facilitate other forms of attack such as denial of service (DoS), where they flood the target system with irrelevant messages to clog traffic and then redirect IP addresses.

How to prevent an ARP Poisoning attack?

What is ARP Poisoning Attack? What can be done to prevent? Picture 2

ARP Poisoning attacks have negative effects on your system, such as loss of important data, reputational damage due to your sensitive data being exposed, and even downtime if attackers tamper with network drivers.

If you don't want to suffer any of the above consequences, here are ways to prevent ARP Poisoning attacks.

1. Create a static ARP table

ARP technologies cannot automatically authenticate legitimate IP addresses by their MAC addresses. This gives cybercriminals an opportunity to spoof ARP responses. You can work around this vulnerability by creating a static ARP table where you map all the authentic MAC addresses on your network to their legitimate IP addresses. Both components will only connect and process their matching addresses, eliminating the opportunity for attackers to connect their MAC addresses to the network.

Building static ARP tables involves a lot of manual work which makes it time consuming. But if you do your best, you will be able to prevent some ARP Poisoning attacks.

2. Deploy Dynamic ARP Inspection (DAI)

Dynamic ARP Inspection (DAI) is a network security system that verifies ARP components present on the network. It identifies connections with illegal MAC addresses that are trying to redirect or block valid IP addresses.

Dynamic ARP Inspection (DAI) checks all ARP MAC-to-IP address requests on the system and confirms that they are valid before updating the information on the ARP cache and forwarding them to the correct channel.

3. Network segment

The bad guys perform ARP Poisoning attacks, especially when they have access to all areas of the network. Network segmentation means that different components will be in different areas. Even if an intruder gains access to a part, there is a limit to the control they can have since some elements are not present.

You can strengthen your security by creating a static ARP table for each segment of your network. That way, it will be harder for hackers to break into one area, let alone all areas.

4. Data encryption

What is ARP Poisoning Attack? What can be done to prevent? Picture 3

Encryption may not do much in preventing hackers from entering your network with ARP Poisoning attacks, but it will prevent them from modifying your data if they get hold of it. That's because data encryption prevents intruders from reading content without a valid decryption key.

If it is useless for attackers to steal data from an ARP Poisoning attack due to encryption, then it cannot be said to be a successful attack.

Isabella Humphrey

Update 24 July 2023