ARP Spoofing Using Bettercap

Introduction to ARP Spoofing with Bettercap

ARP spoofing is a technique that allows attackers to intercept data in a network by positioning themselves between the target device and the router. This technique, also known as ARP poisoning, exploits the vulnerabilities in the Address Resolution Protocol (ARP).

Using Bettercap, an ethical hacking tool, we can execute ARP spoofing attacks to understand network vulnerabilities. This guide demonstrates how attackers can intercept network traffic, view URLs, websites, and even capture sensitive information like usernames and passwords.

How ARP Spoofing Works

In an ARP spoofing attack, the attacker sends falsified ARP messages to place their device between the target and the router. This "man-in-the-middle" position allows the attacker to intercept, modify, or monitor all network traffic.

Becoming the Man in the Middle with Bettercap

Bettercap provides a powerful ARP spoof module that simplifies this attack. To understand how to use this module, you can use the help command to see available options:

help arp.spoof

Essential ARP Spoof Commands

# Turn on ARP spoofing
arp.spoof on

# Cut the connection of the target
arp.ban on

# Turn off ARP spoofing
arp.spoof off

# Turn off connection banning
arp.ban off

Configuring the ARP Spoof Module

Key Module Options

The ARP spoof module has several configurable parameters:

# See current settings
arp.spoof

# Set full duplex mode (spoof both router and target)
set arp.spoof.fullduplex true

# Specify target devices by IP address
set arp.spoof.targets 10.0.2.7

# Target multiple devices
set arp.spoof.targets 10.0.2.5,10.0.2.7

Understanding Full Duplex Mode

The arp.spoof.fullduplex option determines how the attack operates:

• true - Spoofs both the router and the target, placing the attacker in the middle of the connection. This allows for complete traffic interception but may trigger router ARP protection mechanisms.
• false (default) - Only spoofs the target machine. This is less detectable but limits the attacker's ability to inject content into responses from the router.

Running the ARP Spoofing Attack

Step 1: Set up Bettercap

First, ensure that Bettercap is running and the network reconnaissance modules are active:

# Start network discovery
net.probe on
net.recon on

Step 2: Configure the ARP Spoof Module

Set your targets and configure the module:

set arp.spoof.fullduplex true
set arp.spoof.targets 10.0.2.7

Step 3: Launch the Attack

Start the ARP spoofing module:

arp.spoof on

If no errors appear, the module is running successfully. You can verify active modules with the help command.

Step 4: Verify the Attack

On the target Windows machine, run the following command to check if the MAC address associated with the router's IP has changed:

arp -a

On your Kali machine, check your MAC address with:

ifconfig

If successful, the MAC address shown for the router on the target machine will match your attacker's MAC address.

Implications of Successful ARP Spoofing

When ARP spoofing is successful:

• All traffic from the target intended for the router passes through the attacker's machine
• With full duplex enabled, responses from the router also pass through the attacker
• The attacker can intercept usernames, passwords, URLs, and other sensitive data
• Traffic can be read, modified, or blocked entirely