The concept of zero trust network and its principles

Ruth C. | December 31, 2020

A zero trust network treats all users as equally unreliable and prioritizes strict identity verification. This security architecture stands as an alternative to the traditional castle-and-moat model. In the latter, devices and people working within the security perimeter receive access privileges automatically. Zero trust networks do not rely on locality and treat all users and devices as dangerous, regardless of their position in the perimeter. By doubting the legitimacy of systems and traffic within a data center, we build a more resilient network security architecture.

Why is the castle-and-moat approach no longer practical?

Castle-and-moat security has been the traditional practice for decades. The classic Trojan Horse story accurately presents its flaws. The city of Troy had impenetrable walls, defending them from invaders. However, once enemies penetrated this defense, they rampaged and destroyed everything in sight. The castle-and-moat model also overly focuses on the external threats and underestimates the potential dangers within the trusted perimeter.

Therefore, perimeter-based security architecture can no longer stay resistant to intensifying threats. Usually, it employs proxy servers, firewalls, honeypots, and other intrusion prevention techniques. The perimeter security protects the entry and exit points but assumes that activities inside are reasonably benign.

However, companies rarely operate on-premise data centers: they take advantage of cloud or container environments. Hence, companies manage dispersed networks, consisting of information and applications available to employees, customers, and partners. As a result, perimeter-based security might not cover enough ground to protect all data.

The castle-and-moat architecture may perform splendidly in terms of keeping villains out. Unfortunately, it does not consider that insiders could become perpetrators or have their identities compromised. It is also safer to assume that network systems operate with undiscovered loopholes. Zero trust networks work on this principle, and many services have equipped them for better security.

What is a zero trust network?

The zero trust network is a philosophy aiming to debunk the outdated belief that there are trusted networks. It is a renowned security architecture model, reinventing the way networks prevent unauthorized access. Nowadays, companies operate more endpoints and have employees working from multiple locations. Additionally, perimeter security is not impenetrable, as hackers continue to develop creative solutions to work around them. Zero trust networks address both behavioral and infrastructural shifts and provide a next-level model for stopping attackers. Instead of relying on locality, zero trust networks automatically assume that systems are in danger. Therefore, more robust authentication and authorization standards grant access according to user and device characteristics.

Zero trust networks become superior as they do not treat the internal networks and activity within them as harmless. Instead, it expects attackers in both internal and external networks. Its goals and operation reflect in the five principles zero trust networks follow:

  • Perceiving all networks as hostile.
  • Verifying users, devices, and network traffic with detailed authentication and authorization processes.
  • Assuming that threats exist in all networks around-the-clock.
  • Introducing policies from a range of data sources.
  • Eliminating network locality as a decisive factor when granting access.

To summarize, a zero trust network does not make assumptions about systems being safe or dangerous. Instead, it eliminates the trust element and implements the “never trust; always verify” motto. Furthermore, network segmentation is highly relevant to zero trust networks. The rule is that companies should split networks (presumably by using switches). The latter division allows companies to carefully control access privileges or implement the “Least Privileged” access policy. It gives employees access to essential resources, but anything beyond that remains out of reach.

Technologies and attitude changes with zero trust networks

The zero trust network approach relies on a range of technologies to implement its vision. Encryption, multi-factor authentication, IAM (Identity and Access Management), orchestration, micro-segmentation, and file system permissions are only a few. Therefore, the zero trust concept does not usually represent a specific tool, but rather a combination of them. It is essential to recognize users’ identities, endpoint type, and security status. Then, companies can establish further conditional guidelines for halting or permitting access.

However, the switch to zero trust network model is not all about implementing technical changes. Employees receiving the least amount of access for their tasks might find it challenging to readjust. They might be too comfortable with the current security mechanisms such as firewalls halting unauthorized access. Therefore, before prioritizing zero trust networks, educate your employees about their benefits.

Furthermore, breaking up with perimeter-based security might be a lengthy process. Some systems won’t handle transitions easily (for example, legacy systems). Therefore, these changes might take a long time. It is best to start with environments ready for these transitions (such as cloud).

Zero trust networks for more effective security

The shift to zero trust networks will render useful, especially in terms of mitigating data breaches. In the castle-and-moat model, attackers can access one part of the network to steal information from another. In the zero trust network, perpetrators won’t have the luxury to move around the network. The granular access to resources based on users’ identities and context introduces a more resistant security posture.

Ruth C.

Ruth C.

Cybersecurity Researcher and Publisher at Atlas VPN. Interested in cybercrime, online security, and privacy-related topics.


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