Course 14 - Wi-Fi Pentesting | Episode 4: Cracking WEP Encryption: Gaining Network Access

In this lesson, you’ll learn about:What WEP encryption is and why it is weakHow the RC4 algorithm is used (and broken) in WEPHow Initialization Vectors (IVs) cause WEP to failCapturing WEP traffic using Airodump-ngCracking WEP keys using Aircrack-ngSpeeding up WEP cracking on idle networksUsing fake authentication and packet injectionPreparing for post-connection attacks after cracking WEPCracking WEP Encryption Why WEP Is Weak WEP (Wired Equivalent Privacy) is an old Wi-Fi encryption method that uses:RC4 encryption algorithmA shared secret key for encryption and decryptionHow WEP works:The access point generates a 24-bit Initialization Vector (IV)The IV is combined with the network passwordTogether they generate a keystreamThis keystream encrypts the packetsThe IV is sent in plain text with every encrypted packetWhy this is dangerous:A 24-bit IV is very smallOn busy networks:IVs repeat very quicklyRepeated IVs allow:Statistical attacksTools like Aircrack-ng to recover the keystreamThe WEP password to be crackedCracking WEP in Practice The attack process consists of two main stages: 1. Capturing Data (IV Collection)Use Airodump-ng to capture packetsPackets are saved into a capture fileThe “data” counter represents:The number of unique IVs collectedThe higher the data count:The higher the success rateOn busy networks:IVs increase very fastCracking can take only minutes2. Cracking the KeyUse Aircrack-ng on the captured fileAircrack-ng performs:Statistical analysisRC4 weaknesses exploitationOnce the key is recovered:You can connect to the networkYou gain full network accessHandling Idle Networks If the network is not busy:IV collection becomes extremely slowCracking may take many hours or longerTo solve this, attackers force packet generation 1. Fake Authentication (Association) Before injecting packets, the attacker must:Associate with the target networkAssociation means:The access point accepts your deviceEven though you are not fully connectedThis is done using:aireplay-ng fake authentication attackThis tells the access point:“I am a valid client”Association is required so:The access point does not ignore injected packets2. Packet Injection After successful association:The attacker injects packets into the networkThis forces the access point to:Generate large numbers of new packetsCreate new IVs very quicklyThe IV count rises:From a few hundredTo tens of thousands in minutesThis allows:Very fast WEP crackingEven on a completely idle networkAfter Cracking the Key Once the WEP key is recovered:You can:Connect to the Wi-Fi network normallyIntercept trafficGather sensitive informationPerform man-in-the-middle attacksModify data in transitThis prepares you for:All post-connection attacksCovered in later lessonsYou can listen and download our episodes for free on more than 10 different platforms:https://linktr.ee/cybercode_academy