What is a MAC spoofing attack? Learn how it works and how to detect and prevent it

What is MAC spoofing?

To understand MAC spoofing, you need to know what a MAC address is. A MAC (media access control) address is a series of characters that identifies a particular device on a network and helps it communicate with other devices. It consists of 12 letters and numbers and is assigned to a network interface card of each device.

By extension, MAC spoofing is a technique to change the original MAC address of a network device to a different one. It hides the real identity of a device or mimics another device on the same network.

IT professionals use MAC spoofing to test network security and identify vulnerabilities, while users may spoof their MAC address to maintain privacy and prevent tracking while using public Wi-Fi networks.

Is MAC spoofing illegal?

No, MAC spoofing itself is not illegal and can be used for legitimate purposes, such as improving network security measures. However, it is illegal to carry out MAC spoofing attacks to gain unauthorized access to networks or steal data.

A MAC spoofing attack is when an attacker intentionally changes their device’s MAC address to mimic your device’s MAC address and redirect the data sent to your device to another one. Because the attacker’s device has the same MAC address as your device, the network will treat it as if it were your device. This way attackers can bypass the cybersecurity of a network they want to access and launch a man-in-the-middle attack. A MAC spoofing attack is typically a step in a larger cyberattack aimed at intercepting, altering, or stealing sensitive information.

How does a MAC spoofing attack work?

In a MAC spoofing attack, the hacker changes their device’s MAC address to match a legitimate device’s address, connects to the network, and intercepts or redirects data. Here’s a breakdown of the process:

1. They change their device’s MAC address to match the MAC address of a legitimate device on the targeted network.
2. They connect their device to the network, where a switch (on wired networks) or a wireless access point (on wireless networks) manages data traffic.
3. The attacker’s device, now with the spoofed MAC address, can receive data intended for the legitimate device or monitor network traffic for sensitive information.
4. The attacker intercepts or redirects data or launches further attacks.

MAC spoofing attack techniques

Hackers use several MAC spoofing techniques in their cyberattacks. Here are the main ones:

• Manual MAC address change. Attackers manually change their computer’s MAC address through network settings or command line tools.
• MAC spoofing software. Hackers use dedicated software tools to automate the process of changing their own computer’s MAC address to the stolen address.
• Network driver modifications. Attackers alter their computer’s network driver settings to change its MAC address.
• MAC cloning is an attack in which hackers copy the MAC address of a legitimate device to their own device.
• Randomizing a MAC address involves attackers regularly changing their MAC address to random values to avoid detection and tracking.

Network attack techniques involving MAC spoofing

Some broader network attack techniques also involve MAC spoofing as a component:

• Packet injection. This can involve MAC spoofing if the attacker uses a spoofed MAC address to send forged data packets to deceive network devices.
• ARP spoofing. In these attacks, hackers send fake Address Resolution Protocol (ARP) messages to link their MAC address with the IP address of a legitimate device on the network.
• DHCP spoofing is a type of attack where cybercriminals set up a rogue DHCP server to assign IP addresses and network configurations, linking their MAC address to legitimate IP addresses. Attackers might use MAC spoofing to appear as legitimate devices when interacting with other network components.
• MAC flooding. In these attacks, hackers overwhelm a network switch with fake MAC addresses, causing it to enter a fail-open state and send all traffic to all ports. Although the primary aim is to overwhelm the switch with fake MAC addresses, attackers might also use MAC spoofing to disguise their identity during the attack.

How to detect a MAC spoofing attack

To detect MAC spoofing attacks, monitor your network traffic for unusual patterns or multiple devices using the same MAC address. Also, regularly check ARP tables for inconsistencies, such as multiple IP addresses linked to a single MAC address.

You should also deploy Intrusion Detection Systems (IDS) to identify and alert you to spoofing activities. You can configure switches with port security to limit the number of MAC addresses per port and shut down ports if spoofing is detected.

MAC spoofing attack example

So how do these attacks look in real life? Let’s look at a scenario in which attackers are targeting a bank. They might change their computer’s MAC address to match that of a bank employee’s computer. This way, they could gain access to the bank’s network, payment system, or sensitive client information.

How to prevent a MAC spoofing attack

These sneaky attacks might be difficult to spot and no less difficult to prevent. First, you should use encryption to protect network data, making it harder for attackers to read or alter it if they get their hands on it.

You can implement access control lists (ACLs) to limit network access to approved MAC addresses and segment the network into smaller subnets to limit the spread of attacks. It’s also useful to enhance port security by configuring switches to allow only specific MAC addresses and use Dynamic ARP Inspection (DAI) to validate ARP requests and responses.

Use MAC address tracking tools to monitor for unusual or duplicate MAC addresses on the network. And as mentioned in the spoofing detection part of our blog post, make sure to regularly monitor your network traffic for unusual patterns, deploy IDS, and scan for duplicate MAC addresses. Also, apply authentication protocols so that only authorized devices can connect to the network.

What to do if you fall victim to a MAC spoofing attack

If you think you were hit by a MAC spoofing attack, you should immediately secure your devices and network. Here are the steps you should take:

1. Immediately disconnect the affected device from the network to keep the hacker out.
2. Change all network passwords, including Wi-Fi and admin passwords, to prevent the attacker from accessing the network again.
3. Scan your network for duplicate MAC addresses and identify the unauthorized devices.
4. Enhance your network security by enabling stronger encryption, setting up ACLs, and configuring port security on your switches.
5. Turn on DAI to validate ARP requests and responses to prevent future spoofing attacks.
6. Use network traffic monitoring tools to keep an eye on traffic patterns and detect any suspicious activity.
7. If needed, consult with IT security professionals to thoroughly check and secure your network against further attacks.

FAQ

Is MAC spoofing a wireless attack?

No, MAC spoofing attacks can target both wired and wireless networks, depending on the type of network the hacker is trying to infiltrate.

Why would a hacker want to spoof a MAC address?

A hacker might spoof a MAC address to sneak into a network by pretending to be a trusted device. This can help them avoid detection, access restricted areas, or intercept data they shouldn’t be able to see. It’s like using a fake ID to get into a place where you’re not allowed.

What is the difference between MAC spoofing and MAC flooding?

MAC spoofing involves changing a device’s MAC address to impersonate another device on the network and gain unauthorized access. It tricks a switch into thinking the attacker’s device is the legitimate one. MAC flooding, on the other hand, involves overwhelming a network switch with fake MAC addresses, causing it to enter fail open mode and act like a hub. This forces the switch to send all traffic to all ports, potentially allowing the attacker to capture sensitive data.