EAP-FAST: Secure Authentication with Flexible Tunneling

 EAP-FAST

EAP-FAST (Flexible Authentication via Secure Tunneling) is an Extensible Authentication Protocol (EAP) method developed by Cisco. It is designed to provide secure communication between a client and an authentication server using Transport Layer Security (TLS) to establish a mutually authenticated tunnel.

How EAP-FAST Works

• TLS Tunnel Establishment: The process begins with a TLS handshake to create a secure tunnel between the client and the server. This tunnel protects the exchange of authentication information.
• Protected Access Credentials (PACs): PACs optimize the authentication process. They consist of a shared secret and other information that helps establish the secure tunnel.

Two-Phase Authentication:

• Phase 1: Establishes the secure tunnel using the PAC.
• Phase 2: The client and server exchange authentication data within the tunnel using Type-Length-Value (TLV) objects.

Benefits of EAP-FAST

• Mutual Authentication: The client and server authenticate each other, ensuring secure communication.
• Immunity to Attacks: The protocol is designed to prevent passive dictionary attacks and man-in-the-middle attacks.
• Flexibility: Supports various password authentication methods like MS-CHAP, LDAP, and OTP.
• Efficiency: Optimized for environments with limited computational and power resources, such as wireless networks.

EAP-FAST is often used in wireless networks and point-to-point connections to provide secure session authentication without client-side certificates.

This is covered in Pentest+ and Security+.