Introduction
Wireless security has always been a concern, and understanding the vulnerabilities of different encryption protocols is crucial for both security professionals and enthusiasts. In this guide, we will delve into the process of cracking WEP (Wired Equivalent Privacy) encryption, a less secure protocol, and explore the technique of generating fake traffic to aid in the cracking process.
Essential Tools for WEP Cracking
1. airmon-ng: airmon-ng is a command-line utility used to enable and disable monitor mode on wireless interfaces. Monitor mode allows the wireless card to capture all packets transmitted on a particular channel, regardless of the network to which the card is connected. This mode is essential for tasks such as packet sniffing and network analysis.
Usage:
airmon-ng start <interface>
airmon-ng stop <interface>
start: Initiates monitor mode on the specified wireless interface.stop: Disables monitor mode on the specified wireless interface.
2. airodump-ng: airodump-ng is a powerful tool for capturing and displaying information about wireless networks. It provides details about nearby access points, including BSSID (MAC address), signal strength, channel, encryption type, and connected clients. Additionally, it can be used to capture raw packets for later analysis.
Usage:
airodump-ng <interface>
airodump-ng --bssid <bssid> --channel <channel> --write <file_name> <interface>
Captures information about nearby wireless networks.
Allows targeting a specific network using BSSID and channel.
Captures data and saves it to a file for further analysis (we will be dealing with the .cap file here)
3. aireplay-ng: aireplay-ng is a tool for injecting traffic into a wireless network. It is commonly used for testing the security of Wi-Fi networks and generating the necessary traffic to speed up the process of capturing initialization vectors (IVs) required for WEP key cracking. aireplay-ng can perform tasks like fake authentication and packet injection.
Usage:
aireplay-ng --fakeauth <count> -a <bssid> -h <your_own_Mac_address> <interface>
aireplay-ng --arpreplay -b <bssid> -h <your_own_Mac_address> <interface>
--fakeauth: Performs fake authentication to a wireless network.--arpreplay: Injects ARP (Address Resolution Protocol) packets into the network to generate additional traffic.
4. aircrack-ng: aircrack-ng is a suite of tools used for the penetration testing of wireless networks. It includes tools for capturing packets, performing dictionary attacks on WPA and WPA2-PSK passwords, and, as mentioned in the guide, cracking WEP encryption. The aircrack-ng tool specifically attempts to crack the WEP key by analyzing captured packets and identifying the correct key through various methods.
Usage:
aircrack-ng <file_name-01.cap>
Analyzes captured packets to attempt to crack the WEP key.
Can be used with captured data from
airodump-ngto recover WEP passwords.
Understanding Managed and Monitor Modes
In managed mode, the wireless network interface card (NIC) functions as a standard client, enabling connections to Wi-Fi networks for regular user devices. It facilitates association with access points, data transmission, and typical network operations. On the contrary, monitor mode transforms the NIC into a powerful tool for passive monitoring. In this mode, the NIC captures and analyzes all wireless traffic within its range, independent of network associations. Monitor mode is particularly valuable for tasks like packet sniffing, network analysis, and security auditing, offering a versatile approach to understanding and troubleshooting wireless networks.
Quick Note: Identifying Interface Name with "ifconfig" on Linux
When you find yourself needing to check the network interface name on your Linux system, the ifconfig command simplifies the task. Just follow these brief steps:
Launch your terminal
Enter
ifconfig: Type and execute the command:ifconfigInspect the Output: In the displayed information, look for labels like "eth0" (Ethernet) or "wlan0" (Wi-Fi). These labels represent your network interfaces.
Identify Yours: Find the entry corresponding to your network connection, and there you have it – your network interface name.
Cracking WEP Encryption:
Step 1: Enter Monitor Mode
Begin by putting your wireless interface into monitor mode to capture packets from nearby networks.
airmon-ng start wlan0
Step 2: Gather Information
Run airodump-ng with interface name to collect information about nearby routers.
airodump-ng wlan0mon
Identify the target router's BSSID and channel. Start capturing data with the following command:
airodump-ng --bssid <bssid> --channel <channel> --write <file_name> wlan0mon
Step 3: Aircrack-ng and Handshake Capture
Open a new terminal and use aircrack-ng to analyze the captured data and attempt to crack the WEP key.
aircrack-ng <file_name-01.cap>
The saved file captures not only packets but also the critical handshake, which is a part of the authentication process where the WEP key is exchanged between devices on the network. This handshake is essential for later attempts at decrypting the WEP key.
Connect a device to the target network and generate traffic by browsing or downloading to speed up the cracking process.
Step 4: Retrieve the Key
Once the key is found, note it down along with the "key found" message. Save this information for later use.
Connecting to the Cracked Network:
Step 5: Shutdown and Restart
Restart the system and open the notepad containing the cracked WEP key. This step is crucial because sometimes what happens is while performing this attack even after when you move back from monitor to managed mode, you won't be able to connect to the internet. Even service NetworkManager restart won't work. That's why we shutdown or restart our system.
Step 6: Remove Colons and Copy Key
Remove colons from the key inside the brackets. Copy the key.
Step 7: Connect to the Network
Access the Wi-Fi settings, select the target router, paste the key, and connect.
Step 8: Verify Connection
Ensure internet connectivity by pinging a reliable website.
Understanding Initialization Vectors (IVs) in WEP:
Initialization Vectors (IVs) are crucial elements in the WEP encryption process. IVs are used to initialize the encryption algorithm and are transmitted along with the data packets. In WEP cracking, a higher number of IVs increase the chances of successfully recovering the WEP key.
During the airodump-ng and aireplay-ng stages, the captured IVs are integral to the process of generating fake traffic and attempting to crack the WEP key. The more IVs captured, the higher the likelihood of success in deciphering the encrypted network key.
Generating Fake Traffic for WEP:
It will generate some IVs along the way and we will gather those IVs for cracking the password of WEP.
Step 9: Fake Authentication
Repeat the first three steps from the WEP cracking process. Open a new terminal and use aireplay-ng for fake authentication.
aireplay-ng --fakeauth 0 -a <bssid> -h <your_own_Mac_address> wlan0mon
Step 10: ARPreplay
Inject more packets using arpreplay to generate additional traffic.
aireplay-ng --arpreplay -b <bssid> -h <your_own_Mac_address> wlan0mon
Step 11: Crack with Aircrack-ng
Finally, run aircrack-ng on the captured data to crack the WEP key.
aircrack-ng <file_name-01.cap>
Conclusion:
Understanding the vulnerabilities of WEP encryption is essential for securing wireless networks. However, it is crucial to use this knowledge responsibly and only in ethical and legal scenarios. Stay informed, keep networks secure, and always respect privacy and legality.
Disclaimer: This guide is intended for educational purposes only, and any unauthorized access to computer networks is illegal. Use this information responsibly and only on networks you have explicit permission to test.
Do not try this with your neighbors!😉