The technology that can check a client's health before allowing access to the network is Network Access Control (NAC).
Understanding Network Access Control (NAC)
Network Access Control (NAC) is a robust security solution that enforces security policies on devices attempting to connect to a private network. Its primary function is to assess the security posture, or "health," of a client machine before granting it full or even partial access. This preventative measure significantly enhances network security by ensuring that only compliant and secure devices can connect, thereby minimizing potential attack vectors.
NAC operates by establishing a set of policies that define the minimum security requirements a device must meet. When a device attempts to connect, NAC evaluates it against these predefined criteria.
How NAC Checks Client Health
NAC solutions perform a series of checks to determine the compliance and health status of an endpoint. These checks can include:
- Antivirus/Anti-malware Status: Verifying that antivirus software is installed, updated, and actively running.
- Operating System Patch Level: Ensuring that the operating system has the latest security updates and patches installed to address known vulnerabilities.
- Firewall Status: Confirming that the host-based firewall is enabled and properly configured.
- Presence of Required Software: Checking for the installation of essential security software or specific enterprise applications.
- Disallowed Software: Identifying and flagging the presence of unauthorized or malicious software.
- Device Configuration: Assessing device settings, such as strong password policies, disabled guest accounts, or encrypted drives.
These comprehensive checks are crucial for maintaining a strong security posture across the entire network.
The Access Control Process
The process by which NAC controls network access typically involves several stages:
- Authentication: The device or user attempts to connect to the network.
- Posture Assessment (Health Check): The NAC solution assesses the device's security health based on predefined policies. This can happen pre-admission (before any network access) or post-admission (while on a restricted network segment).
- Policy Enforcement: Based on the assessment, NAC applies an appropriate access policy.
NAC Enforcement Actions
| Health Status | Action Taken by NAC | Description |
|---|---|---|
| Compliant | Full Network Access | Devices that meet all security requirements are granted full access to the corporate network resources. |
| Non-Compliant | Quarantine/Limited Access | Devices failing to meet security policies are typically placed in a quarantine network segment. This segment provides limited access, often only to remediation servers where users can update antivirus software, install patches, or resolve other issues. Once remediated, the device is re-evaluated for full access. |
| Blocked | No Network Access | In cases of severe non-compliance or known malicious activity, NAC can completely deny network access to the device. |
Benefits of Implementing NAC
Implementing NAC offers significant security and operational benefits for organizations:
- Enhanced Security: Prevents unhealthy or non-compliant devices from introducing threats to the network.
- Regulatory Compliance: Helps organizations meet various industry regulations and compliance standards by enforcing strict security policies.
- Improved Visibility: Provides a centralized view of all devices attempting to connect to the network, their health status, and access privileges.
- Automated Remediation: Automates the process of identifying non-compliant devices and guiding them through remediation steps.
- Reduced Manual Effort: Decreases the need for manual intervention in managing network access and ensuring device compliance.
- Support for BYOD (Bring Your Own Device): Securely manages the integration of personal devices into the corporate network by enforcing appropriate policies.
By ensuring that only trusted and healthy endpoints can connect, NAC plays a crucial role in maintaining the integrity and security of modern enterprise networks.
