ZTNA: Zero Trust Network Access

What is ZTNA (Zero Trust Network Access)?

Zero Trust Network Access, also known as software-defined perimeter (SDP), is a modern approach to securing access to applications and services both for users in the office and on the road. How ZTNA works is simple: deny everyone and everything access to a resource unless explicitly allowed. This approach enables tighter network security and micro-segmentation that can limit lateral movement if a breach occurs.

With legacy network solutions based on VPN, authenticated users implicitly gain access to everything on the same subnet. Only a password prevents unauthorized users from accessing a resource. ZTNA flips that paradigm. Users can only “see” the specific applications and resources explicitly permitted by their company’s security policy.

 

ZTNA Use Cases

ZTNA fits many use cases. Here are some of the most common:

  • VPN Alternative – Connect mobile and remote users more securely than legacy VPN. ZTNA is more scalable, provides one security policy everywhere, works across hybrid IT, and offers more fine-grained access. Gartner projected that by 2023, 60% of enterprises would switch from VPN to ZTNA.
  • Reduce third-party risk – Give contractors, vendors, and other third parties access to specific internal applications — and no more. Hide Sensitive Applications – Render applications “invisible” to unauthorized users and devices. ZTNA can significantly reduce the risk posed by insider threats.
  • Secure M&A integration – ZTNA reduces and simplifies the time and management needed to ensure a successful merger or acquisition and provides immediate value to the business.

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How Does ZTNA Work?

ZTNA is not only more secure than legacy network solutions, but it’s designed for today’s business. Legacy networks assumed a secure network perimeter with trusted entities inside, and untrusted entities outside. Today the perimeter is gone. Users work everywhere — not only in offices — and applications and data are increasingly moving to the cloud. Access solutions need to be able to address those changes.

With ZTNA, application access can dynamically adjust based on user identity, location, device posture, and more. ZTNA is a cloud-based service that accepts connections from both managed and unmanaged devices, verified identity, and authorizes access to company assets- whether in an on-premises data center or in the cloud.ZTNA Architecture

The 4 Functions of ZTNA

ZTNA performs four essential functions:

  • Identify – map all systems, applications and resources that users may need to access from remote.
  • Enforce – define the access conditions policies under which specific individuals can or cannot access specific resources.
  • Monitor – log and analyze all access attempts of remote users to resources, making sure enforced policies adhere to the business requirements.
  • Adjust – modify misconfiguration. Either increase access privileges or reduce to support optimal productivity while minimizing risk and exposure.

ZTNA User Flow

The ZTNA user workflow looks like the following:

  1. Over a secure channel, a user connects to and authenticates against a Zero Trust controller (or a controller function). MFA (multi-factor authentication) is used for added security.
  2. The controller implements the necessary security policy, which depending on implementation, could check various device attributes, such as the device certificate and presence of current antivirus, and real-time attributes such as the user’s location.
  3. Once the user and device meet the specified requirements, access is granted to specific applications and network resources based upon the user’s identity.

 

How ZTNA works

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How to Implement ZTNA?

There are two primary approaches to implementing ZTNA. One is agent-based and the other is service-based.

Agent-Based ZTNA

In agent-based ZTNA, an agent installed on an authorized device sends information about that device’s security context to a controller. This context typically includes factors such as geographic location, date, and time as well as deeper information such as whether the device is compromised with malware or not. The controller prompts the user on the device for authentication.

After both the user and the device are authenticated, the controller provisions connectivity from the device through a gateway. The gateway shields applications from being accessed directly from the internet and from unauthorized users or devices. The user can only access applications that are explicitly allowed.

The illustration below shows a conceptual model of agent-based ZTNA.

Source: Gartner (April 2019), ID: 386774

Service-Based ZTNA

In service-based ZTNA, a connector installed in the same network as the application establishes and maintains an outbound connection to the provider’s cloud. Users that request access to the application are authenticated by a service in the cloud, which is followed by validation by an identity management product such as a single sign-on tool. Application traffic passes through the provider’s cloud, which provides isolation from direct access and attack via a proxy.

Note that no agent is required on the user’s device, making this a good option to provide connectivity and access to applications from unmanaged devices.

The illustration below shows a conceptual model of service-based ZTNA.

Source: Gartner (April 2019), ID: 386774

ZTNA and SASE

With Secure Access Service Edge (SASE) the ZTNA controller function becomes part of the SASE PoP and there’s no need for an SDP connector. Devices connect to the SASE PoP, get validated and users are only given access to those applications (and sites) allowed by the security policy in the SASE Next-Generation Firewall (NGFW).

But ZTNA is only a small part of Secure Access Service Edge (SASE). Once users are authorized and connected to the network, IT leaders still need to protect against network-based threats. They still need the right infrastructure and optimization capabilities in place to protect the user experience. And they still need to manage their overall deployment.

SASE addresses those challenges by bundling ZTNA with a complete suite of security services — NGFW, SWG, anti-malware, and MDR — and with network services such as SD-WAN, WAN optimization, and a private backbone.

Enterprises that leverage SASE receive the benefits of Zero Trust Network Access plus a full suite of network and security solutions, all converged together into a package that is simple to manage, optimized, and highly scalable.

Related resources:

What is Zero Trust Architecture?

Zero trust architecture is a design that implements zero trust principles, namely applying granular access controls and only trusting endpoints that are explicitly granted access to a given resource. Zero Trust Architecture represents a fundamental shift from traditional castle-and-moat solutions such as Internet-based VPN appliances for remote network access. With those traditional solutions, once an endpoint authenticates, they have access to everything on the same network segment and are only potentially blocked by application-level security. Learn more about zero trust architecture and how it works today.

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Explaining the Zero Trust Framework

A zero trust network enforces a zero trust security model, where access to corporate resources is granted or denied on a case-by-case basis driven by role-based access controls. We explain how developing a zero trust network is a multi-stage process, including identifying a “protect surface,” determining how the network works, and deploying micro-segmentation to enforce zero-trust policies.

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Zero Trust Principles: What is Zero Trust?

Zero trust has become a well-known buzzword due to its ability to improve corporate cybersecurity and network visibility. Zero trust is based on the principle that access to corporate assets should only be granted to legitimate users on a case-by-case basis. We take a look at the core principles of zero trust and how to implement a zero trust strategy within your organization.

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The Evolution of Zero Trust Security and 5 Key Components

Recent changes to the security landscape, such as the transition to remote work and the growth in supply chain attacks, emphasize the need for zero trust. Understand the key drivers of zero trust security, and the main technologies that make up the zero trust security stack.

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Zero Trust Network: Why You Need It and 5 Steps to Get Started

In the past, network security was mainly based on defending the perimeter. Systems like firewalls and intrusion detection/prevention systems (IDS/IPS) were deployed at the network edge, and were tasked with stopping intruders from penetrating the network. In a zero trust network, these tools are still used, but are complemented with advanced measures to stop attackers while already inside the corporate network.

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Secure the Remote Workforce: Deploying Zero Trust Access

Global Workplace Analytics estimates that 25-30% of the workforce will be working from home multiple days a week by the end of 2021. What does this mean for the remote access worker? Organizations must adjust to make it very quick and easy to give highly secure access to any and all remote workers.

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How to Implement Zero Trust: 5 Steps and a Deployment Checklist

Zero Trust Solutions: 5 Solution Categories and How to Choose

Zero trust solutions are security toolkits that incorporate network access controls and security measures to implement the principle of zero trust, which regards all users and entities as potentially malicious until proven safe. Implementing zero trust networks often requires organizations to combine multiple tools and processes.

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The Gartner ZTNA Market Guide for Secure Access

With the shift to work from home (WFH) there’s been a lot of talk about VPN and its successor, zero trust network access (ZTNA). But ZTNA is in fact far broader than “just” more secure remote access for your workforce. It describes a whole new access paradigm that’s key to SASE and reflects the changes to today’s business.

Gartner detailed the ZTNA paradigm shift in its updated Market Guide for Zero Trust Network Access. The 18-page document provides an excellent overview of ZTNA technology, where it’s headed, the risks and the opportunities.

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FAQ

  • What is Zero Trust Network Access (ZTNA)?

    Zero Trust Network Access is a modern approach to securing access to applications and services. ZTNA denies everyone and everything access to a resource unless explicitly allowed. This approach enables tighter network security and micro-segmentation that can limit lateral movement if a breach occurs.

  • How is ZTNA different from software-defined perimeter (SDP)?

    SDP and ZTNA today are functionally the same. Both describe an architecture that denies everyone and everything access to a resource unless explicitly allowed.

  • Why is ZTNA important?

    ZTNA is not only more secure than legacy network solutions, but it’s designed for today’s business. Users work everywhere — not only in offices — and applications and data are increasingly moving to the cloud. Access solutions need to be able to reflect those changes. With ZTNA, application access can dynamically adjust based on user identity, location, device type, and more.

  • How does ZTNA work?

    ZTNA uses granular application-level access policies set to default-deny for all users and devices. A user connects to and authenticates against a Zero Trust controller, which implements the appropriate security policy and checks device attributes. Once the user and device meet the specified requirements, access is granted to specific applications and network resources based upon the user’s identity. The user’s and device’s status are continuously verified to maintain access.

  • How is ZTNA different from VPN?

    ZTNA uses an identity authentication approach whereby all users and devices are verified and authenticated before being granted access to any network-based asset. Users can only see and access the specific resources allowed to them by policy.

    A VPN is a private network connection based on a virtual secure tunnel between the user and a general terminus point in the network. Access is based on user credentials. Once users connects to the network, they can see all resources on the network with only passwords restricting access.

  • How can I implement ZTNA?

    In client-initiated ZTNA, an agent installed on an authorized device sends information about that device’s security context to a controller. The controller prompts the device’s user for authentication. After both the user and the device are authenticated, the controller provisions connectivity from the device through a gateway such as a next-generation firewall capable of enforcing multiple security policies. The user can only access applications that are explicitly allowed.
    In service-initiated ZTNA, a connector installed in the same network as the application establishes and maintains an outbound connection to the provider’s cloud. A user requesting access to the application is authenticated by a service in the cloud, followed by validation by an identity management product. Application traffic passes through the provider’s cloud, which provides isolation from direct access and attack via a proxy. No agent is needed on the user’s device.

  • Will ZTNA replace SASE?

    ZTNA is only a small part of SASE. Once users are authorized and connected to the network, there is still a need to protect against network-based threats. IT leaders still need the right infrastructure and optimization capabilities in place to protect the user experience. And they still need to manage their overall deployment.
    SASE addresses those challenges by bundling ZTNA with a complete suite of security services — NGFW, SWG, anti-malware, and MDR — and with network services such as SD-WAN, WAN optimization, and bandwidth aggregation.

  • What security capabilities does ZTNA lack?

    ZTNA addresses the need for secure network and application access but it doesn’t perform security functions such as checking for malware, detecting and remediating cyber threats, protecting web-surfing devices from infection, and enforcing company policies on all network traffic. That’s why the full suite of security services in SASE is a complement to ZTNA.

  • How do Zero Trust and SASE work together?

    With SASE, the ZT controller function becomes part of the SASE PoP and there’s no need for a separate connector. Devices connect to the SASE PoP, get validated and users are only given access to those applications (and sites) allowed by the security policy in the SASE Next-Generation Firewall (NGFW) and Secure Web Gateway (SWG).

    SASE addresses other security and networking needs by bundling ZTNA with a complete suite of security services — NGFW, SWG, anti-malware, and MDR — and with network services such as SD-WAN, WAN optimization, and bandwidth aggregation. Enterprises that leverage SASE receive the benefits of Zero Trust Network Access plus a full suite of network and security solutions, all converged together into a package that is simple to manage, optimized, and highly scalable.

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