Lightweight Extensible Authentication Protocol (LEAP)

Lightweight Extensible Authentication Protocol (LEAP) is a proprietary authentication protocol developed by Cisco Systems, primarily designed for use in wireless networks. Here’s an overview of LEAP and its key features:

Key Features

1. Mutual Authentication: LEAP provides mutual authentication, allowing both the client and the server to verify each other’s identities during the authentication process.

2. Dynamic Keying: LEAP supports dynamic key generation, which helps improve security by generating unique session keys for each authentication session.

3. Password-Based Authentication: LEAP uses usernames and passwords for authentication, but it also employs techniques to protect those credentials during transmission.

4. Designed for Wireless Networks: LEAP was specifically developed to address the needs of wireless LAN environments, where traditional authentication methods may be less effective.

How It Works

1. Initialization: The client requests access to the network and sends its identity to the authentication server.

2. Challenge: The server responds with a challenge, prompting the client to provide its password.

3. Response Generation: The client combines its password with the challenge and computes a response, which is sent back to the server.

4. Verification: The server checks the response against its records. If it matches, the client is authenticated, and a session key is established.

Advantages

• Enhanced Security: By using dynamic keying and mutual authentication, LEAP improves security over simpler methods like PAP.
• Compatibility: LEAP is supported by many Cisco devices and is designed for use in Cisco-centric environments.

Disadvantages

• Vulnerability to Attacks: LEAP has known vulnerabilities, particularly to dictionary attacks, where attackers can capture packets and attempt to guess passwords.
• Proprietary Protocol: Being proprietary, LEAP may not be supported across all devices and platforms, limiting its versatility.

Alternatives

Due to its vulnerabilities and the emergence of more secure protocols, LEAP has largely fallen out of favor in modern networks. Some alternatives include:

• EAP-TLS: Uses certificates for strong mutual authentication and is widely considered secure.
• EAP-PEAP: Combines the security of TLS with a username/password mechanism, providing a more secure way to authenticate users without exposing credentials.