What is WEP (Wired Equivalent Privacy) and why is it not secure?
Here's a technical breakdown of WEP and why it is considered insecure:
- Encryption Algorithm:
- WEP uses the RC4 stream cipher for data confidentiality. RC4 is a symmetric key algorithm, meaning the same key is used for both encryption and decryption.
- Key Management:
- WEP relies on a static key model, where a fixed key is shared among the wireless devices. This key is manually configured on both the access point and all the connected devices. Due to the manual nature of key distribution, managing and updating keys becomes challenging.
- Initialization Vector (IV):
- WEP employs a 24-bit Initialization Vector (IV) to add randomness to the encryption process. However, the 24-bit size is relatively small, leading to a limited number of possible IVs. As a result, IV reuse occurs, making it vulnerable to certain attacks.
- Key Size:
- WEP supports key sizes of 40 or 104 bits. A 40-bit key length is considered weak by modern standards and can be easily brute-forced. Even the 104-bit key size, while more secure, is not robust enough against advanced attacks.
- Weaknesses:
- The combination of the static key, small IV size, and weak key management makes WEP susceptible to various attacks. The most notable is the Fluhrer, Mantin, and Shamir (FMS) attack and the more practical and powerful KoreK chopchop attack. These attacks exploit the vulnerabilities in the WEP algorithm and can recover the key with relatively little effort.
- Lack of Authentication:
- WEP only provides encryption and lacks a robust authentication mechanism. This means that an attacker can eavesdrop on the communication, inject malicious packets, or even impersonate a legitimate device on the network.
- Widespread Cracking Tools:
- Over the years, several freely available tools, such as Aircrack-ng, have been developed to exploit WEP vulnerabilities. These tools make it relatively easy for attackers to compromise WEP-protected networks.