Understanding the Zero Trust Security Model

What Is the Zero Trust Security Model? 

The zero trust security model is a framework for security that assumes every user, device, and system within an organization’s network is potentially untrusted and must be verified before being granted access to resources. In a zero trust model, there is no assumption of trust based on network location or user identity.

The zero trust model seeks to address the weaknesses of traditional perimeter-based security models, which rely on a network’s perimeter (e.g., a firewall) to keep out threats. In a zero trust model, access to resources is granted on a per-request basis, and all requests are authenticated and authorized before being granted. This means that even if an attacker manages to gain access to a network, they will still need to go through the proper authentication and authorization processes in order to access resources.

To implement a zero trust model, organizations typically use a combination of technologies and processes, such as multi-factor authentication, network segmentation, and microsegmentation. The goal of the zero trust model is to create a security posture that is more resilient to attacks and can better protect against threats that manage to bypass traditional perimeter defenses.

This is part of a series of articles about DevSecOps.

In this article:

• Why Is the Zero Trust Security Model Important?
• Zero Trust Use Cases
• How the Zero Trust Security Model Works
• Best Practices for Implementing Zero Trust Security
• Identify the Resources that Need to Be Protected
• Implement the Principle of Least Privilege
• Implement Zero Trust Policies
• Establishing Continuous Monitoring and Improvement

Why Is the Zero Trust Security Model Important? 

Zero trust security is important because it helps organizations to better protect themselves against cyber threats. In a traditional security model, an attacker who is able to gain access to a network is able to move laterally within that network and potentially compromise other systems. This can lead to data breaches and other serious security incidents.

With a zero trust security model, an attacker who is able to gain access to a network is unable to move laterally and is therefore unable to compromise other systems. This means that even if an attacker is able to gain access to a network, the potential damage that they can do is greatly reduced. This makes it much harder for attackers to successfully carry out their attacks and helps to protect organizations from the potential consequences of a security breach.

Zero Trust Use Cases 

There are several use cases for the zero trust security model:

• Third parties: Organizations often need to share resources or collaborate with third parties, such as vendors, partners, or customers. In a zero trust model, access to resources can be granted on a per-request basis and can be restricted to specific resources or functions. This can help to prevent unauthorized access to sensitive resources and can improve security when working with third parties.
• Remote workers: The proliferation of remote work has made it more challenging to secure networks and systems. In a zero trust model, access to resources can be granted based on the user’s identity and the device they are using, rather than their location. This can help to secure remote access and can make it easier for organizations to support remote work.
• IoT security: The Internet of Things (IoT) refers to the network of connected devices that are embedded in everyday objects, such as smart thermostats, security cameras, and industrial control systems. These devices can be a source of security vulnerabilities if they are not properly secured. In a zero trust model, access to IoT devices can be controlled and restricted based on the device’s identity and the resources it is requesting access to. This can help to secure IoT networks and reduce the risk of attacks.
• Data center microsegmentation: Data centers often contain a large number of servers and other devices that are connected to the same network. In a zero trust model, access to resources within the data center can be segmented and controlled on a granular basis, using techniques such as microsegmentation. This can help to limit the scope of an attack and can make it more difficult for an attacker to move laterally within the data center.

How the Zero Trust Security Model Works 

Zero trust networks work by eliminating trust by default and implementing multiple controls to verify entities and restrict access. There are several basic functions that are typically included in a zero trust network:

• Identity and access management: Users, devices, and systems are identified and authenticated before being granted access to resources. This can involve using technologies such as multi-factor authentication, which requires users to provide additional forms of authentication beyond just a password.
• Network segmentation: A zero trust model typically involves segmenting the network into smaller, more secure segments. This can help to limit the scope of an attack and can make it more difficult for an attacker to move laterally within the network.
• Microsegmentation: Access to resources within a segmented network can be further granularized. This involves creating small, isolated security zones within the network that can be accessed only by authorized users or devices.

Best Practices for Implementing Zero Trust Security 

The following practices can help you implement a zero trust architecture.

Identify the Resources that Need to Be Protected

The first step in implementing a zero trust model is to identify the resources that need to be protected. This can include data, systems, applications, and other assets. This is known as the “protect surface”—similar to the “attack surface.” Different resources will have different security requirements. It is important to assess the sensitivity of each resource and determine the appropriate level of security for each one.

Identifying the attack surface is also important, as it helps to mitigate vulnerabilities and weaknesses that could potentially be exploited by an attacker.

Implement the Principle of Least Privilege

The principle of least privilege (POLP) is a security best practice that involves granting users, processes, and systems only the minimum level of access necessary to perform their duties. It provides the following benefits:

• Limits the scope of an attack: If an attacker manages to compromise a user’s account or a system, they will not have access to sensitive resources or other parts of the network.
• Reduces the risk of insider threats: Employees might intentionally or unintentionally misuse their access to cause harm. By granting users only the minimum level of access necessary, organizations can reduce this risk.
• Improves compliance: Many regulations and industry standards require organizations to implement the principle of least privilege in order to protect sensitive information. By implementing the principle of least privilege, organizations can help to meet these requirements and improve their compliance posture.

Implement Zero Trust Policies

Implementing zero trust policies is an important best practice, as it helps organizations to establish clear guidelines and procedures for managing access to resources in a zero trust model. These policies can help to ensure that access is granted only to authorized users and devices, and that all requests for access are properly authenticated and authorized.

A zero trust policy should outline the process for verifying the identity of users, devices, and systems before granting access to resources. This can include requirements for multi-factor authentication and other forms of identity verification.  

Establishing Continuous Monitoring and Improvement

Continuous monitoring and optimization help organizations to continuously assess the security of their networks and systems and make adjustments as needed. By monitoring security, organizations can identify and mitigate vulnerabilities, respond to security incidents, and optimize their security posture.