MAC Addresses: Understanding, Importance, and Security in Networking

Have you ever wondered what a MAC address ? Let's explore it in detail.

In this blog, we will learn about MAC addresses in detail. We will also learn why it is necessary to change your MAC address.

What is MAC, and how does it work?

Let's go back to school and recall what a MAC address is. A MAC (Media Access Control) address is a special, physical and permanent number that is mainly assigned by the device manufacturer.

Let us explore it in more detail:

A typical structure of a network:

Consider that your home's router has five devices connected to it. Any network interface, including Ethernet cables and Wi-Fi, can be used to link these devices to the router. The internet serves as a resource in this scenario, and the router serves as the access point.

A small cable plugged into your router's rear gives it access to the web. Supposing Device 1 is interested in finding a specific video on YouTube. The packets representing the request are then sent from the device to the router serving as the access point. The router will then attempt to locate the media file on the network. After the router sends this packet to the device requesting the video, the user will see the expected result.

If, for example, every device is connected to the access point via Wi-Fi, then every packet will be transmitted over the air, and anyone using the network can capture and examine the packets (which we will do as we go along the section). Every packet has its own source MAC address (in this instance, device 1) and a destination MAC address (in this instance the router).

A visual representation of network and communication with the server

The Role of MAC and IP:

MAC address:

The MAC address facilitates communication between the various devices or access points within the network. Also, the access points use the MAC address to identify the device when the user requests a specific resource.

IP address:

Although each device has a distinct IP address, the MAC address serves as a means of communication between users' devices that are part of the same network, as opposed to the IP address, which is used to connect computers to the internet.

Types of MAC addresses

There are three types of MAC addresses:

Universal MAC address (UAA):

UAAs, or manufacturer-assigned MAC addresses, are used with NICs by default. You may also hear these referred to as "burned-in addresses" (BIA) or "physical addresses."

Locally Administered MAC Address (LAA):

Instead of being allocated by the manufacturer, a locally administered address (LAA) is given by the network administrator or end user. Changing a device's MAC address before moving it from one network to another is a common practise to prevent any potential network collisions.

Multicast MAC address:

Sending a message to a collection of network nodes at once requires the usage of a multicast MAC address. After the "01-00-5E" prefix, there are an extra three octets that specify the multicast group.

How MAC addresses are structured?

A colon or dash separates the pairs of digits that make up the 12-digit, 48-bit MAC address. The OUI (organizationally unique identifier) is the first 12 digits assigned by the IEEE (Institute of Electrical and Electronics Engineers). The first 12 digits of the MAC address are used to identify the device's manufacturer. The manufacturer assigns the remaining 12 digits of the MAC address to identify the specific device. You can find your Kali Linux MAC address by running the command "ifconfig."

Let us understand the structure of the MAC address through an example:

Let us say that your MAC address is 01-2A-43-9B-12-84.

The first 6 digits, i.e., 01-2A-43, represent the OUI.

The next 6 digits, i.e., 9B-12-84, represent the device identifier.

Why would you want to change your MAC address?

Increase anonymity:

When your MAC address changes, so does your network identity. This makes it difficult to trace back to the original device, and, as a result, you become somewhat anonymous.

Impersonate others:

By changing your MAC address, you can pose as an authentic source and thus avoid some filters. Let us use your office network as an example. Each node is linked to a single router, either via Ethernet or wirelessly. Assume there is an employee login portal with a username and password field, and there is a filter that says that if the packet source is from the admin's MAC address, the password field is not required. If you can change your MAC address to the admin's MAC address, you can easily bypass the filter and skip the password field, which was required in this scenario. As a result, changing the MAC address is advantageous for ethical hackers.

TO LEARN HOW TO CHANGE YOUR MAC ADDRESS IN KALI LINUX CLICK HERE

HAPPY HACKING :)