AAA VPN Authentication

Using AAA and RADIUS to authenticate VPNs
Using RADIUS for AAA VPN policy

Local vs Centralized
Set up the ASA to use RADIUS
Using the AAA server

Local means vpn user account is configured on ASA. Centralized means using ACS i.e AAA server for authentication, vpn users password is maintained on server. When request comes in, ASA check with ACS server for vpn user password validity. If ACS server gives thumbs up then user is let in . This is scalable solution. Mainly used when we have multiple ASA’s, routers. we need not to maintain separate user account on all devices. we can have one user account on sever to authenticate that particular VPN user and we can configure all devices as clients for this server. We can have fault tolerance for ACS server as well. Instead of having user account on server we can also apply policies for that particular user on AAA server. Any profile information that is pulled down from LDAP or AAA to ASA, we can use that information to apply policies for that user such as custom ip address for that user.

ACS is cisco product that can be either use with RADIUS or TACACS protocol. ACS server called as AAA server which can be used for authentication , authorization and accounting.

Lets use cisco ACS as AAA server and ASA as client. ASA talk to AAA server using Radius or TACACs+ protocol. User accounts must be created on AAA server. Usually, for VPN, RADIUS is used to communicate between ASA and AAA server. In real scenario this AAA server might be connected to LDAP or some windows domain.

When user tries to login to ASA using its credentials, ASA will ask AAA server for password validity. AAA server can say yes/no based on config, also it can provide lot of attributes associate with user back to ASA

The first step to authenticate the user is by using connection-profile. In connection-profile, we can say that if any user log in use AAA server for authentication. This way we tell connection profile how to use server group.

Which connection profile to use ?
Drop-down option
configured special url
some type of certificate mapping where client present the certificate and based on certificate and its values ASA decide which connection profile to use.

To configure AAA server group on ASDM:
Configuration -> Device Management -> USers/AAA -> AAA server Groups

Multi factor authentication:
using username password , biometric access and digital cert
ASA can act as a facilitator for multi factor authentication.

We can also use both LOCAL and ACS server for authentication. LOCAL as primary and AAA as secondary for authentication.

We can also do authentication with LOCAL and authorization and accounting with AAA server group.

AAA VPN authentication refers to the use of AAA (Authentication, Authorization, and Accounting) protocols and services for authenticating users connecting to a VPN (Virtual Private Network) infrastructure. AAA VPN authentication provides a centralized and flexible mechanism for verifying the identities of VPN users, enforcing access policies, and logging user activities for auditing and accounting purposes.

Here's how AAA VPN authentication works:

1. **Authentication**: AAA VPN authentication involves verifying the identity of VPN users before allowing them to establish VPN connections. During the authentication process, users provide credentials, such as usernames and passwords, which are validated against a centralized authentication server or database. AAA protocols commonly used for VPN authentication include RADIUS (Remote Authentication Dial-In User Service), TACACS+ (Terminal Access Controller Access-Control System Plus), and LDAP (Lightweight Directory Access Protocol).

2. **Authorization**: Once a user is successfully authenticated, AAA VPN authentication determines the level of access or privileges the user is granted within the VPN environment. Access policies and permissions are defined based on user roles, groups, or attributes stored in a centralized authorization server or directory. Authorized users are granted access to specific VPN resources, such as networks, applications, and services, based on their assigned permissions.

3. **Accounting**: AAA VPN authentication tracks and logs user activities and resource usage for auditing, billing, and compliance purposes. Accounting records are generated for each VPN session, capturing details such as user login/logout timestamps, duration of the session, data transferred, and resources accessed. These accounting records can be stored centrally and used for reporting, analysis, and billing purposes.

Benefits of AAA VPN authentication include:

- Centralized Management: AAA VPN authentication provides centralized management of user authentication, authorization, and accounting processes, simplifying administration and ensuring consistency across the VPN infrastructure.

- Flexible Access Control: AAA VPN authentication allows administrators to define granular access control policies based on user identities, roles, groups, and attributes, enabling fine-grained control over VPN access and privileges.

- Scalability: AAA VPN authentication scales to support large numbers of VPN users and devices, making it suitable for enterprise-scale deployments with diverse user populations and access requirements.

- Auditing and Compliance: AAA VPN authentication facilitates auditing and compliance efforts by generating detailed logs of user activities and resource usage, helping organizations track and monitor VPN access for security and regulatory compliance purposes.

Overall, AAA VPN authentication enhances the security, manageability, and accountability of VPN deployments by providing a robust framework for authenticating users, enforcing access policies, and monitoring user activities within the VPN environment. It is widely used in enterprise networks, service provider environments, and managed VPN services to ensure secure and compliant access to corporate resources.