Multi Factor Authentication

MFA for Network Devices Using RADIUS

Instasafe Marketing

• 9 min read
MFA for Network Devices Using RADIUS
MFA for Network Devices Using RADIUS

Traditional password-based authentication cannot protect against advanced cyber attacks. In this blog, we'll explore the concept of multi-factor authentication using RADIUS, its benefits, implementation and best practices. We'll understand what RADIUS is, how it works with MFA, and why this combination is crucial for modern network security.

What is RADIUS?

Remote Authentication Dial-In User Service, or RADIUS, is a networking system that manages users' authentication, authorisation and accounting (AAA) from a central location. It lets users connect to and use network services.

Originally developed for dial-up networks, RADIUS has evolved to become a standard for various network access scenarios, including Wi-Fi, VPN, and other remote access methods.

Also Read: What is RADIUS Authentication and How Does it Work?

RADIUS MFA

RADIUS MFA, also known as RADIUS 2FA (two-factor authentication), integrates the centralised authentication capabilities of RADIUS with the enhanced security of multi-factor authentication. This combination provides a robust solution for securing network access across various scenarios.

How RADIUS MFA Works

  1. User initiates a connection request to a network resource.
  2. The RADIUS client (e.g., VPN server, Wi-Fi access point) sends a request to the server.
  3. The MFA RADIUS server verifies the initial credentials (usually username and password).
  4. If the initial authentication is successful, the RADIUS server triggers an MFA challenge.
  5. The user provides the additional authentication factor (e.g., enters a one-time password from a smartphone app).
  6. The RADIUS server verifies the second factor and sends the final authentication result to the RADIUS client.
  7. Based on the result, the user is either granted or denied access to the network resource.

Benefits of Implementing RADIUS MFA

  1. Centralised Management: Organisations can manage authentication policies and user access from a central RADIUS server, simplifying administration and ensuring consistent security across different network access points.
  2. Flexibility: RADIUS MFA can be implemented across various network scenarios, including VPN access, Wi-Fi networks and remote desktop connections.
  3. Compliance: Many industry regulations and standards require or recommend multi-factor authentication. Implementing RADIUS MFA can help organisations meet these compliance requirements.
  4. User Experience: While adding an extra step to the login process, RADIUS MFA can be implemented in user-friendly ways, such as push notifications or biometric authentication on smartphones.
  5. Scalability: RADIUS servers are designed to handle large numbers of authentication requests, making RADIUS MFA suitable for organisations of all sizes.

Implementing RADIUS MFA

To set up RADIUS MFA, organisations need to consider the following components and factors:

RADIUS Server

The MFA RADIUS server is the central component of the authentication system. It can be dedicated hardware or software running on a server. Popular RADIUS server solutions include:

  • InstaSafe Zero Trust: InstaSafe controller acts as a RADIUS server and receives authentication requests from RADIUS clients, such as routers, firewalls, or VPNs, verifies the credentials of the user, and returns an authorization decision to the client.
  • FreeRADIUS (open-source): A highly configurable and widely used open-source RADIUS server that supports various authentication methods and can integrate with multiple backends.
  • Microsoft Network Policy Server (NPS): Integrated with Windows Server, NPS provides RADIUS server functionality and policy management for Windows environments.
  • Cisco Identity Services Engine (ISE): A comprehensive network administration product that includes RADIUS server functionality, particularly suited for Cisco network environments.
  • RSA Authentication Manager: Offers RADIUS server functionality along with robust multi-factor authentication capabilities.

When choosing a RADIUS server, consider factors such as:

  • Scalability: Ensure the server can handle your current and projected authentication loads.
  • Supported Authentication Methods: Verify compatibility with your desired MFA methods.
  • Integration Capabilities: Check if it can integrate seamlessly with your existing infrastructure and identity management systems.
  • Management Interface: Look for user-friendly administration tools to simplify configuration and maintenance.
  • Support and Documentation: Evaluate the availability of vendor support and community resources.

MFA Solutions

To add multi-factor authentication to your RADIUS setup, you'll need an MFA solution that integrates with your RADIUS server. Some popular MFA solutions include:

  • InstaSafe MFA: InstaSafe multi factor authenticator app provides various authentication methods including T-OTP, Biometrics Authentication, MPIN, Hardware token, push notification, and more.
  • Google Authenticator: A widely-used, free mobile app for generating time-based one-time passwords (TOTP).
  • RSA SecurID: Provides hardware tokens and mobile apps for strong two-factor authentication, often used in enterprise environments.
  • Microsoft Azure Multi-Factor Authentication: Integrated with Azure Active Directory, offering various authentication methods, including phone calls, text messages and mobile app verification.

Consider factors such as:

  • Supported Authentication Methods: Ensure the solution offers the MFA options you prefer (e.g., push notifications, OTP, biometrics).
  • User Experience: Look for solutions that provide a smooth, intuitive authentication process.
  • Integration Capabilities: Verify compatibility with your chosen RADIUS server and other systems.
  • Management and Reporting: Evaluate the solution's administrative features and reporting capabilities.
  • Cost: Consider both upfront and ongoing costs, including per-user licensing fees.

RADIUS Clients

RADIUS clients are the network access devices that users connect to, such as:

  • VPN servers (e.g., Cisco ASA, Palo Alto Networks, Fortinet FortiGate)
  • Wi-Fi access points and controllers
  • Network switches and routers
  • Remote desktop gateways
  • Cloud service connectors

Ensure that your RADIUS clients supports:

  • The authentication methods you plan to use
  • Secure communication with your RADIUS server (e.g., support for RADIUS over TLS)
  • Any specific RADIUS attributes required for your MFA implementation

User Directory

RADIUS servers often integrate with existing user directories such as:

  • Active Directory: Microsoft's directory service, widely used in enterprise environments.
  • LDAP (Lightweight Directory Access Protocol): A standard protocol for accessing and maintaining distributed directory information.
  • Local User Database: Some RADIUS servers can maintain their own user database for smaller deployments.

Choose a MFA RADIUS server that can integrate with your organisation's user directory to:

  • Simplify user management by leveraging existing user accounts and groups
  • Maintain consistent access policies across different systems
  • Enable single sign-on (SSO) capabilities where appropriate

Network Infrastructure

Consider the impact of implementing RADIUS MFA on your network infrastructure:

  • Ensure your network can handle the additional authentication traffic, especially during peak times.
  • Implement redundancy and load balancing for high availability:
  • Set up multiple RADIUS servers to prevent single points of failure
  • Use load balancers to distribute authentication requests across multiple servers
  • Secure the communication between RADIUS clients and servers:
  • Use RADIUS over TLS (RadSec) for encrypted communication
  • Implement IPsec tunnels for additional security, especially for remote RADIUS clients
  • Consider the placement of RADIUS servers in your network topology:
  • Ensure they are accessible to all RADIUS clients while maintaining security
  • Consider deploying RADIUS servers in multiple geographic locations for global organisations

User Experience and Training

Implementing RADIUS MFA will change the login process for your users. Consider these to ensure a smooth transition:

  • Choose user-friendly MFA methods:
  • Push notifications are often preferred for their ease of use
  • Consider biometric options for seamless authentication on supported devices
  • Provide clear instructions and training for users on the new authentication process:
  • Create step-by-step guides for different devices and scenarios
  • Offer video tutorials for visual learners
  • Implement a smooth rollout plan:
  • Start with a pilot group to identify and address any issues
  • Gradually expand to more users, providing support along the way
  • Set up a helpdesk process to assist users with MFA-related issues:
  • Train support staff on common MFA problems and solutions
  • Establish procedures for resetting or re-enrolling MFA factors

Security Policies and Procedures

Develop and implement security policies and procedures around your RADIUS MFA deployment:

  • Define password policies that complement MFA (e.g., complexity requirements, rotation schedules)
  • Establish procedures for handling lost or compromised authentication factors
  • Create policies for temporary access or bypass procedures in case of emergencies
  • Develop an incident response plan for potential authentication-related security incidents

Steps to Implement RADIUS MFA

The procedures for deploying RADIUS MFA may vary based on your solutions and infrastructure:

Plan and Design

  • Identify the network resources that require MFA protection.
  • Choose your RADIUS server and MFA solution.
  • Design the network architecture and communication flow.

Set Up the RADIUS Server

  • Install and configure your chosen RADIUS server software.
  • Integrate the RADIUS server with your user directory.
  • Configure RADIUS clients (network access devices) in the MFA RADIUS server.

Implement the MFA Solution

  • Set up the MFA server or cloud service.
  • Integrate the MFA solution with your RADIUS server.
  • Configure MFA policies and authentication methods.

Configure RADIUS Clients

  • Set up each RADIUS client (e.g., VPN server, Wi-Fi access point) to communicate with the RADIUS server.
  • Configure encryption and shared secrets for secure communication.

Test the Setup

  • Perform thorough testing with different user scenarios and device types.
  • Verify that authentication requests are properly handled and logged.

User Enrollment and Training

  • Enrol users in the MFA system (e.g., distribute hardware tokens or help them set up smartphone apps).
  • Provide training and documentation on the new login process.

Rollout and Monitoring

  • Implement RADIUS MFA in phases, starting with a pilot group if possible.
  • Monitor system performance and user experience.
  • Address any issues or user feedback promptly.

Best Practices for RADIUS MFA Implementation

To ensure a successful and secure RADIUS MFA deployment, consider the following best practices:

  • Use Strong Encryption: Implement strong encryption for communication between RADIUS clients and servers to protect against eavesdropping and man-in-the-middle attacks.
  • Implement Redundancy: Set up multiple RADIUS servers to ensure high availability and prevent authentication failures due to server downtime.
  • Regular Updates: Keep your RADIUS server, MFA solution and all associated components up to date with the most recent security updates.
  • Secure Configuration: Follow security best practices when configuring your RADIUS server and MFA solution, such as using strong passwords and limiting administrative access.
  • Logging and Monitoring: Implement comprehensive logging and monitoring to detect and respond to suspicious authentication attempts or system issues.
  • User Education: Provide ongoing user education about the importance of MFA and best practices for securing their authentication factors (e.g., not sharing OTP codes).
  • Periodic Review: Regularly review and update your RADIUS MFA policies and configurations to ensure they align with your organisation's evolving security needs.
  • Backup and Recovery: Implement strong backup and recovery procedures for your RADIUS server and MFA solution to ensure business continuity in case of system failure.

Challenges and Considerations with RADIUS MFA

While RADIUS MFA offers significant security benefits, there are some challenges to consider:

  1. Complexity: Implementing RADIUS MFA can add complexity to your network infrastructure and may require additional expertise to manage effectively. Proper planning and documentation are crucial to mitigate this challenge.
  2. User Resistance: Some users may resist the additional authentication step, perceiving it as an inconvenience. Address this through clear communication about security benefits and by choosing user-friendly MFA methods.
  3. Cost: Depending on the chosen solutions, implementing RADIUS MFA may involve additional costs for software licences, hardware tokens, or cloud services.
  4. Integration Issues: Ensuring smooth integration between the RADIUS server, MFA solution and existing infrastructure can be challenging, especially in complex environments. Thorough testing and possibly engaging with professional services can help overcome integration hurdles.
  5. Performance Impact: Adding MFA to the authentication process may slightly increase login times and server load, which should be accounted for in capacity planning. Proper sizing of RADIUS servers and optimising network connectivity can help mitigate performance concerns.
  6. Legacy System Compatibility: Some older systems or applications may not support modern MFA methods. You may need to develop workarounds or consider upgrading legacy systems to ensure comprehensive MFA coverage.
  7. Mobile Device Dependence: Many MFA solutions rely on smartphones for push notifications or OTP generation. Consider alternatives for users without smartphones or in environments where mobile devices are restricted.

As technology keeps changing, the future of RADIUS MFA will be shaped by a number of trends:

  1. Passwordless Authentication: There's a growing movement towards eliminating passwords entirely, relying instead on strong multi-factor methods like biometrics combined with possession factors.
  2. Continuous Authentication: Rather than authenticating users only at login, systems are moving towards continuous verification throughout a session based on behavioural patterns and contextual information.
  3. Integration with Zero Trust Architectures: RADIUS MFA is becoming a key component in Zero Trust security models, where trust is never assumed, and verification is required from everyone trying to access resources on the network.
  4. Enhanced Biometrics: Advancements in biometric technology, including behavioural biometrics, are making these authentication factors more secure and user-friendly.

Conclusion

Multi-factor authentication using RADIUS (RADIUS MFA) offers a powerful solution for enhancing network security. By using both RADIUS's centralised authentication and multi-factor authentication, businesses can make it much less likely that people will get into their networks and resources without permission.

Our Multi-Factor Authentication makes your network super secure and easy to use. With InstaSafe, you can quickly set up strong 2FA for all your access points, keeping your data safe and your users satisfied.

Frequently Asked Questions (FAQs)

  1. What is the difference between RADIUS Protocol, RADIUS Server and RADIUS Client?
  • RADIUS Protocol is the communication standard.
  • RADIUS Server authenticates and authorises network access requests.
  • RADIUS Client (e.g., router) sends access requests to the server.

Together, they form a RADIUS MFA system for secure network access.

2. Which RADIUS-enabled devices should be protected by MFA?

Any device that acts as a RADIUS client should be protected by MFA. This includes network access servers, VPN concentrators, wireless access points and switches. Implementing RADIUS 2FA enhances security for these critical network entry points.

3. Which is better, Kerberos or RADIUS?

Neither is universally better. Kerberos excels in internal network authentication, while RADIUS is preferred for remote access scenarios. Many organisations use both, with RADIUS MFA servers providing additional security for remote connections.

4. Can RADIUS be used for SSO?

Yes, RADIUS can be part of a Single Sign-On (SSO) solution. When integrated with an MFA RADIUS server, it can provide secure authentication for multiple services. However, RADIUS alone is not a complete SSO system and is often combined with other protocols.

5. Is RADIUS an IdP?

RADIUS isn't typically considered an IdP (Identity Provider). It's an authentication protocol that can work with IdPs. RADIUS servers validate user credentials and manage network access, but they usually rely on external identity sources like Active Directory for user information.