Arpspoof Capture Flag: A Beginner-Friendly Approach to ARP Spoofing

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ARP (Address Resolution Protocol) poisoning is a powerful attack that involves manipulating MAC address resolutions between two devices in order to intercept and modify traffic. In this article, we will delve into the world of arpspoft capture flag attacks using Ettercap's versatile toolset.

Introduction

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Before diving headfirst into ARP spoofing with `arpspoof`, it is essential to understand what Address Resolution Protocol (ARP) actually does. Simply put, ARP resolves IP addresses assigned by a network interface controller (NIC) or router onto the physical MAC address associated with that device on an Ethernet LAN.

Here's how it works in layman terms:

1. When your computer wants to send data over the local area network (LAN), its NIC asks: 'Hey! Who has this IP address?'

2. The switch then forwards a ARP request packet containing source and destination MAC addresses of both devices involved.

3. Upon receiving this request, all other computers on the LAN examine their own cache for an entry matching the target's MAC address.

The Power of Arpspoof

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Now that we have covered some background information about ARP poisoning let's talk about why you might want to use `arpspoof`. This tool is ideal when you need a quick and dirty way to intercept traffic between two devices on your local network without worrying too much about setting up more complex reconnaissance tools like Ettercap.

### Using Arpspoof for Capture-Flag Attacks

To set up an ARP man-in-the-middle (MITM) attack using `arpspoof`, follow these steps:

1. First, make sure you have the `libpcap-dev` and `tcpdump` packages installed on your system.

2. Next, compile Ettercap from source code by running ./configure && make && sudo make install in the directory where you downloaded it.

Now that we've got our tools ready let's move onto actually performing an attack!

### Attacking with Arpspoof

To launch a bidirectional ARP poisoning attack using `arpspoof`, open up your terminal and enter:

```

sudo ./usr/local/bin/arpscan -r 192.168.x.y | tee hosts.txt

./usr/local/bin/ettercap -i eth0 --mitm --restore /root/.hosts

```

Replace the IP address in bold with the target's IP you want to poison.

Once your victim device reconnects, all their traffic will be forwarded through `arpspoof` for inspection and manipulation. To stop the attack simply press Ctrl+C on the terminal where you ran Ettercap.

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In conclusion, we've covered a basic introduction into ARP spoofing using `arpspoof`. While this technique is not particularly sophisticated compared to more advanced attacks like DNS or SSLstrip poisoning, it remains an excellent starting point for those looking to get their hands dirty with network exploitation. Remember always test these techniques in a controlled environment before attempting them on production networks!

References

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* '1' Ettercap's Official Documentation:

Arpspoof capture flag