Macof is a network attack tool used primarily in MAC flooding attacks, which target Ethernet switches to disrupt normal traffic flow and enable packet sniffing. It’s part of the dsniff suite and is commonly used in penetration testing and red-team operations.
💥 What Is Macof?
Macof generates a massive number of fake MAC addresses and floods them into a switch’s Content Addressable Memory (CAM) table. This overwhelms the switch, causing it to behave like a hub — broadcasting traffic to all ports instead of just the intended destination.
🧪 How Macof Works in a Cyber Attack
- Launch Macof on a compromised machine within a local network.
- It sends thousands of Ethernet frames with random source MAC addresses.
- The switch’s MAC address table fills up quickly.
- Once full, the switch enters fail-open mode, broadcasting all traffic to every port.
- The attacker sets their network card to promiscuous mode and begins sniffing traffic — including sensitive data like credentials, emails, or internal communications.
🛠️ Example Command
macof -i eth0
-i eth0: Specifies the network interface to use.- You can also target specific IPs or ports using flags like
-d,-x,-y.
🎯 Real-World Use Case
During a penetration test, an ethical hacker might use Macof to test whether a switch is vulnerable to MAC flooding. If successful, they can monitor internal traffic and identify weaknesses in network segmentation or encryption.
🛡️ Countermeasures Against MAC Flooding
| Defense Strategy | Description |
|---|---|
| Port Security | Limits the number of MAC addresses per switch port |
| 802.1X Authentication | Uses centralized access control to validate devices |
| Dynamic ARP Inspection | Prevents spoofed ARP packets from being accepted |
| Switch Hardening | Configure switches to drop excessive MAC entries or alert on anomalies |
