MAC Address Spoofing: Network Security Risks

G5 Cyber Security

1 week ago

TL;DR

Changing a MAC address (spoofing) doesn’t automatically give an attacker full control, but it can be used to bypass security measures like MAC address filtering. It’s often a stepping stone for more serious attacks and is relatively easy to do.

What is a MAC Address?

A MAC (Media Access Control) address is a unique identifier assigned to your network interface card (NIC). Think of it like the serial number of your device’s network adapter. It’s used for communication within a local network.

Why Would Someone Change Their MAC Address?

Legitimate reasons include:

Troubleshooting network issues
Circumventing access restrictions (e.g., on a Wi-Fi network)
Privacy concerns (though not very effective for true anonymity)

How Can an Attacker Use MAC Address Spoofing?

Here’s how it can be used in attacks:

MAC Address Filtering Bypass: Some networks only allow devices with specific MAC addresses to connect. An attacker could spoof a valid MAC address to gain access.
This is the most common use case.
Man-in-the-Middle (MITM) Attacks: Spoofing can be used in conjunction with ARP poisoning to redirect network traffic through the attacker’s machine, allowing them to intercept and potentially modify data.
More complex, requires additional tools and knowledge.
Denial of Service (DoS): An attacker could repeatedly spoof MAC addresses, disrupting network communication.
Less common but possible.

How to Change a MAC Address

The process varies depending on your operating system:

Windows

Open Command Prompt as an administrator.
Find the network adapter name using
```
ipconfig /all
```
. Look for ‘Physical Address’ under the relevant adapter.
Use the following command, replacing <adapter_name> with your adapter’s name and <new_mac_address> with the desired MAC address (format: XX-XX-XX-XX-XX-XX):
```
getmac /v /force /d  
```
Restart the adapter or your computer.

Linux

Find the network interface name using
```
ifconfig -a
```
.
Bring down the interface:
```
sudo ifconfig  down
```
Change the MAC address, replacing <interface_name> and <new_mac_address>:
```
sudo ifconfig  hw ether 
```
Bring up the interface:
```
sudo ifconfig  up
```

macOS

Open Terminal.
Find the network interface name using
```
ifconfig -a
```
.
Bring down the interface:
```
sudo ifconfig  down
```
Change the MAC address, replacing <interface_name> and <new_mac_address>:
```
sudo ifconfig  ether 
```
Bring up the interface:
```
sudo ifconfig  up
```

How to Protect Against MAC Address Spoofing

Use Stronger Authentication: Rely on more robust security measures like 802.1X authentication (using usernames and passwords) instead of just MAC address filtering.
This is the most effective solution.
Port Security: On managed switches, enable port security to limit which MAC addresses can connect to each port.
Requires network administration access.
Network Monitoring: Implement tools that detect and alert on unexpected MAC address changes.
Can help identify suspicious activity.
Regular Security Audits: Regularly review your network security configuration to ensure it’s up-to-date and effective.