Zero Trust Architecture in Modern Applications

Introduction

Traditional security models operate on the assumption that once a user has successfully logged into the system, they can be trusted at all times. “Zero Trust”, as the name implies challenges this assumption by being skeptical of the identity of user at all times. It does so by enforcing strict identity verification mechanisms, providing least possible privileges and continuously monitoring the user as long as they are in the system.

In this articles, lets understand the basic principles of “Zero Trust Architecture” and explore different strategies that are used when designing such systems.

Zero Trust Principles

“Zero Trust” operates on the principle “never trust, always verify”. In other words, it never makes any assumption and trusts the entity. Each request is verified on a number of factors to ensure the associated identity.

Key Tenets of Zero Trust:

1. Verify Explicitly – Authenticate and authorize every request using variety of signals, such as user identity, device state, and context.

2. Enforce Least Privilege Access – Grant users only the minimum level of permissions necessary to perform their tasks.

3. Assume Breach – Design systems assuming that they have already been compromised, enforcing strong network segmentation, logging and real-time monitoring.

By adopting these principles, organizations can prevent unauthorized access, detect anomalies faster, and minimize the blast radius of security incidents.

Secure Authentication

Authentication is the first layer of security in a Zero Trust framework. Unlike traditional username-password-based approaches, modern authentication flows emphasize strong identity verification and adaptive security controls. Common strategies opted for implementing secure authentication are:

1. Multi Factor Authentication - In addition to the password, users are expected to provide an additional form of authentication like One-Time Password (for example, a code that is sent to their email or phone number) or biometrics (for example, face-id or finger-print)

2. Passwordless Authentication - This strategy eliminates vulnerabilities associated with using password by using alternative strategies like WebAuthN, biometrics or device based authentication (for example FIDO2)

3. Single Sign On - This strategy allows users to login into a single application and gain access to multiple applications, reducing credential fatigue and security risks.

Secure Authorization

Authorization is the subsequent step to authentication - ensuring users have access to only permitted resources. Common strategies opted for implementing secure authorization include:

1. Role Based Access Control (RBAC) - In this strategy, permissions are granted on the basis of role (for example, “Admin” users could have full access to system while “Regular“ users would have access to only limited data and functionality.

2. Attribute Based Access Control (ABAC) - This is an extension of RBAC but access is controlled based on different attributes. For example, a user may be able to access internal corporate website only if they are on company internal network. The same user would not be able to access the internal corporate website even with necessary credentials.

3. Policy Based Access Control (PBAC) - PBAC uses policy engines to control access to resources. These policies are centrally managed and dynamically evaluated. An example of PBAC is access to watching a movie on streaming platform (like Netflix) only if the user is accessing their account from USA.

4. Just-in-Time (JIT) Privileges - JIT Privileges are granted dynamically for a limited period of time and are automatically revoked later on. For example, a user would be granted to sensitive data for limited time (e.g. 1 day) while debugging an issue, after which their access is revoked.

Monitoring

In addition to authentication and authorization, it is imperative to include a continuous monitoring model. Continuous monitoring is used to detected anomalies in user behavior. For example, a user may log into their account from Asia, but requests for subsequent actions originate from Africa. Having continuous monitoring helps identifies such scenarios by detecting breach and avoid potential major security/privacy incidents.

Conclusion

Zero Trust is not a product but a security mindset. Organizations must continuously evolve their security posture to stay ahead of threats by implementing a variety of the above discussed strategies to minimize the possibility of security breaches.