CyberCode Academy

Course 14 - Wi-Fi Pentesting | Episode 2: Network Fundamentals, Wireless Adapter Setup, and Packet Sniffing Basics

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In this lesson, you’ll learn about:
  • How wireless networks operate and transmit data
  • Why packet sniffing is possible in Wi-Fi environments
  • The role of external USB wireless adapters in security testing
  • What MAC addresses are and how they function in networks
  • The difference between managed mode and monitor mode
  • Enabling monitor mode using airmon-ng and iwconfig
  • Discovering nearby networks using Airodump-ng
Wireless Networking & Packet Sniffing Fundamentals Basic Network Operation A wireless network consists of:
  • Clients (devices such as laptops and phones)
  • An access point (router or server)
The access point acts as:
  • The only gateway to shared resources
  • The connection point to the internet
Communication happens through:
  • Requests and responses
  • Sent in the form of data packets
In Wi-Fi networks:
  • Packets travel through the air
  • Any device within range can potentially:
    • Capture usernames
    • Capture passwords
    • Capture visited URLs
  • This is what makes wireless packet sniffing possible
External USB Wireless Adapter Built-in wireless cards:
  • Usually do NOT support:
    • Monitor mode
    • Packet injection
For security testing, you must use:
  • A specialized external USB wireless adapter
Setup inside Kali Linux (VirtualBox):
  • Plug in the adapter
  • Attach it using:
    • VirtualBox → Devices → USB
  • Kali will recognize it as an interface such as:
    • wlan0
Understanding the MAC Address The MAC Address (Media Access Control) is:
  • A unique physical address
  • Permanently assigned to each network interface
Key roles:
  • Used inside the local network
  • Directs traffic between devices
Packet structure includes:
  • Source MAC
  • Destination MAC
Uses of MAC spoofing:
  • Increasing anonymity
  • Bypassing MAC filtering
  • Avoiding device tracking
Wireless Operating Modes Managed Mode (Default)
  • The wireless card only:
    • Receives packets sent to its own MAC address
  • Normal internet usage mode
Monitor Mode
  • The wireless card:
    • Captures ALL packets in the air
    • Regardless of destination
  • Required for:
    • Packet sniffing
    • Network attacks
    • Security analysis
Enabling Monitor Mode Steps used:
  1. Stop conflicting processes:
    • airmon-ng check kill
  2. Enable monitor mode:
    • Use iwconfig or airmon-ng start wlan0
After activation:
  • The interface switches to monitor mode
  • It can now capture every wireless packet in range
Packet Sniffing with Airodump-ng Airodump-ng allows you to:
  • Discover all nearby Wi-Fi networks
  • Monitor traffic without connecting
Displayed network information includes:
  • ESSID: Network name
  • BSSID: Router MAC address
  • PWR: Signal strength
  • Channel: Wireless channel used
  • Encryption: WPA, WPA2, WEP
  • Cipher: Encryption algorithm
  • Authentication: Access method
Successful Airodump-ng output confirms:
  • The adapter is working correctly
  • Monitor mode is functioning properly
  • The system is ready for wireless security auditing


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CyberCode AcademyBy CyberCode Academy