Introducing the Zero Trust Security Model

Introducing the Zero Trust security model, which operates on the principle of "never trust, always verify." This approach means that access to resources is granted based on strict identity verification and continuous monitoring. Zero Trust helps organizations move away from the traditional perimeter-based security model, which assumes that everything inside the network is safe. By implementing Zero Trust, organizations can reduce the risk of data breaches and unauthorized access. It helps in detecting and mitigating potential threats in real-time. Organizations can achieve a higher level of security by applying Zero Trust principles across their network infrastructure, applications, and data systems. Implementing Zero Trust requires a shift in mindset and a holistic approach to security. Organizations can leverage technologies such as multi-factor authentication, encryption, least privilege access, micro-segmentation, and continuous monitoring to enforce Zero Trust principles effectively.

The Philosophy Behind Zero Trust

The core assumption of this security model is that everyone is compromised. No one is to be trusted (inside or outside the network) unless their identification/device is verified. The main difference between Zero Trust and VPN (Virtual Private Network) is that Zero Trust provides secure access to users on a per-resource basis, regardless of the user's location. Access to applications, resources, and data is not based on location—trust is never assumed by default. Users, irrespective of their location, must be verified and are granted only the minimum access they need.

The Three Pillars of Verification

Zero Trust uses three pillars of verification: identity, context, and security posture. Let’s take a closer look:

• Identity: The security model uses the formula Identification + Authentication + Authorization. Identification refers to the process of uniquely identifying individuals or entities within a system. In the context of Zero Trust, every entity that interacts with the network must first establish its identity. Authentication is the process of verifying the claimed identity of an entity. It ensures that the entity is who or what it claims to be before granting access to resources. Authorization determines what actions an authenticated entity is permitted to perform within the network or on specific resources. It defines the permissions and privileges granted to users, devices, or applications based on their verified identities.
• Context: Context refers to how the user is trying to access the resource or the application. By analyzing the context of the request and comparing it to established security policies, organizations can make more informed decisions about granting access to resources. This aspect of verification adds an extra layer of security by considering factors such as the location of the user, time of access, type of device used, and behavior patterns, adding depth to the authentication process.
• Security Posture: The third pillar of verification focuses on the device the user is connecting in on. The posture refers to the overall security readiness and compliance status of a device (e.g., laptop, smartphone, server) attempting to access network resources within an organization. It involves evaluating various aspects of the device's configuration, software updates, adherence to security policies, and potential vulnerabilities.

Zero Trust Goes Beyond Verification

The security model extends beyond verification. The basic scheme is as follows: When access is granted, it requires continuous monitoring and validation. If any changes happen, they will be reevaluated and revoked as necessary.

• Continuous Monitoring: Zero Trust requires ongoing monitoring of user activities, device behaviors, and network traffic patterns throughout an access session.
• Validation of Changes: If any changes occur during an access session, such as a sudden change in user behavior, unusual data access patterns, or a device's security posture deteriorating, Zero Trust mandates that these changes are promptly reevaluated against established security policies.
• Dynamic Adjustments: Based on the monitoring and validation outcomes, Zero Trust enables dynamic adjustments to access privileges. For instance, access may be temporarily restricted or revoked if suspicious activity or non-compliance with security policies is detected.

Trust Broker: The Core Technology Enabling Zero Trust

Zero Trust Network Access (ZTNA) leverages a Trust Broker to provide secure, application-specific access, ensuring that users are continuously authenticated and authorized, regardless of their location. The Trust Broker is responsible for managing the three pillars of verification above: identification, context, and security posture. It verifies the user's identity, evaluates contextual factors such as device health and location, and assesses the device's security posture before establishing a connection with the specific application.

Depending on where the applications are hosted, the Trust Broker can vary. If applications are accessed through a Secure Access Service Edge (SASE) architecture, the Trust Broker typically resides within the cloud provider's infrastructure. Here, the cloud provider acts as the Trust Broker, overseeing access control and security enforcement. On the other hand, if applications are hosted on-premises, whether in a data center or headquarters location, the Trust Broker may take the form of a traditional network security device like a firewall. In this scenario, the firewall acts as the intermediary ensuring that Zero Trust principles are applied to control access and monitor security posture.

Regardless of its form, the Trust Broker continuously monitors and validates the three pillars of Zero Trust—identification, context, and security posture—throughout the access session. This ongoing monitoring ensures that access remains secure and compliant, promptly responding to any changes or anomalies that may arise.