What is NAC (Network Access Control)?

As networks become increasingly complex and cyber threats continue to evolve, organizations are looking for advanced ways to protect their digital assets. An interesting technology that can help with this is NAC, or Network Access Control. Organizations want to protect their networks against unauthorized access and cyberattacks. This is where NAC comes in. But what exactly is NAC, and why it can be so important for a cybersecurity strategy, we'll explain in this blog.

What is Network Access Control?

Network Access Control (NAC) is a technology and policy framework that helps organizations manage and secure access to their network. The goal of NAC is to grant network access only to trusted and approved devices. This is done through a combination of authentication, authorization, and compliance checks.

NAC works by identifying devices attempting to connect to a network, such as laptops, smartphones, IoT devices, or even virtual machines. It then checks whether these devices comply with the organization's security policies. Devices that do not comply are denied access or restricted to a separate segment where they can't cause damage.

How does NAC work?

NAC uses various technologies and processes, which we try to explain further below.

• Authentication: NAC verifies the identity of users and devices through methods such as username/password, certificates, or multi-factor authentication.
• Evaluation: The system checks whether the device meets security standards, for example whether it has the latest patches, antivirus software, and encryption.
• Access control: Only devices that meet the set requirements are granted access to the network. Other devices can be blocked or restricted to a quarantine network.

Compare it to a club or an exclusive event:

• The doorman: Checks who is allowed in. Does the person have an invitation (authorization)? Is the person dressed appropriately (security requirements)?
• The guest list: Contains pre-approved names (users or devices) that are allowed access.
• The access policy: The rules that determine whether someone is allowed in (for example: only 18+ and dressed appropriately).

NAC works the same way, but on a digital network:

• It checks users and devices before granting access.
• It ensures that only approved users or devices connect.
• It sets rules such as "you must have antivirus software" or "you must connect via a secure connection".

Network Access Control and Cyber Security

NAC plays a crucial role in protecting against cyberattacks. It minimizes risks by:

• Preventing unauthorized access: NAC prevents unknown or unapproved devices from connecting to the network.
• Reducing risks: By enforcing compliance rules, NAC ensures that vulnerable devices don't get access to critical network segments.
• Detecting suspicious activity: NAC can flag and block unusual access patterns.

A. Authentication: Who are you?

Compare this to an ID check:

• Without NAC: Anyone can get in without anyone checking who you are.
• With NAC: You must show your ID, for example by logging in with a username and password or a certificate.

For example:

• Without NAC: Anyone with an ethernet cable or Wi-Fi password can connect to the network.
• With NAC: Only devices or users with an authorized identity can connect.

B. Evaluation: Do you meet the requirements?

Compare this to a health check:

• Without NAC: It doesn't matter whether someone is sick or healthy; everyone gets in.
• With NAC: It's checked whether you're "healthy", such as a device that is up to date with security patches and antivirus software.

For example:

• Without NAC: An infected laptop can connect and infect other devices.
• With NAC: An infected laptop is denied access or sent to a quarantine area.

C. Enforcement: Granting or blocking access

Compare this to a gatekeeper:

• Without NAC: Anyone can move freely around the space.
• With NAC: You only get access to the parts you have permission for.

For example:

• Without NAC: A guest can wander through the entire building, including the server room.
• With NAC: A guest is restricted to public spaces and has no access to the server room.

Pre-Connect NAC

Compare this to someone being checked before the door:

• Application: You're not even allowed to enter the network until you're verified.
• Comparison: A doorman checks guests outside the door before they come in.

Post-Connect NAC

Compare this to a security guard inside:

• Application: You're allowed in, but are then continuously monitored.
• Comparison: A security guard keeps an eye inside on whether you're following the rules.

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NAC & Penetration Testing

Penetration testing, or pentesting, is an essential part of a strong cybersecurity policy. During a pentest, ethical hackers try to identify and exploit weaknesses in a network. NAC can be an important line of defense here. During a pentest, NAC can, for example:

• Restrict access: Ethical hackers can be blocked when attempting to gain unauthorized access to the network.
• Identify weaknesses in policies: A pentest can show whether NAC is correctly configured and whether there are gaps in the policy rules.
• Provide additional insights: Using NAC in combination with pentesting gives organizations a more complete picture of their network security.

During a penetration test, the effectiveness of the Network Access Control solution can therefore be tested. This provides insights and possible improvements you may want to implement in the area of cybersecurity.

Network Access Control important within cybersecurity

Network Access Control is a powerful tool in the fight against cyberattacks. It gives organizations the ability to manage and secure access to their network. For companies that take their security seriously, NAC is an indispensable component. By combining it with penetration testing, organizations can ensure that their network security is not only theoretically but also practically robust.

Want to know more about how NAC can help your organization or how penetration testing provides insight into the weaknesses of your network? Get in touch with us. Our experts are ready to support you in securing your digital environment.