Security - Network Access Control (NAC)

Network Access Control (NAC) is a security approach that aims to enforce policy-based access control to networks. It does so by requiring devices to comply with a set of predefined security policies before they are allowed to access network resources. Here’s a breakdown of its key components and how it works:

Key Components of NAC

  1. Policy Enforcement: NAC systems define and enforce security policies that devices must meet to gain network access. These policies can include software updates, antivirus protection levels, system configurations, and more.

  2. Device Assessment: Before allowing devices access to the network, NAC solutions assess them to ensure they comply with the organization's security policies. This can involve checking for up-to-date security patches, the presence of required security software, and specific configuration settings.

  3. Access Control: Based on the assessment, devices are either granted access, denied, or granted limited access to the network. This access control can be applied at various levels, including per-user, per-device, or per-location.

  4. Post-admission Control: Even after a device is allowed on the network, NAC solutions continue to monitor its compliance status. If a device falls out of compliance (e.g., a new vulnerability is discovered), the NAC system can automatically restrict its access until the issue is resolved.

How NAC Works

  1. Identification and Authentication: Initially, when a device tries to connect to the network, the NAC system identifies and authenticates the device and its user, often integrating with existing directories like Active Directory.

  2. Compliance Check: Once authenticated, the NAC system evaluates the device against the organization's security policies. This involves scanning for antivirus software, checking for security patches, and more.

  3. Access Decision: Depending on the outcome of the compliance check, the NAC system decides whether to allow access, deny access, or place the device on a quarantine network where it must be remediated before gaining full access.

  4. Continuous Monitoring: NAC systems continuously monitor devices on the network. If a device becomes non-compliant, the system can automatically take corrective action, such as quarantining the device or limiting its network access.

Benefits of NAC

  • Enhanced Security: By ensuring only compliant devices can access the network, NAC significantly reduces the risk of malware and other security threats.
  • Visibility: NAC provides visibility into every device on the network, including type, access method, and compliance status, which is crucial for security and management.
  • Compliance: Helps organizations comply with industry regulations and standards by enforcing consistent security policies across the network.

NAC is especially important in environments with a high degree of mobility and with the proliferation of BYOD (Bring Your Own Device) policies, as it helps secure the network against potentially compromised or non-compliant devices.

NAC is not a specific protocol or mechanism, but it is a network security approach. It leverages many technologies involved in security. Many of these include: