Zero Trust Network Access (ZTNA)

What is Zero Trust Network Access (ZTNA)?

Zero Trust Network Access (ZTNA) is a security framework that provides users with secure, identity-based access to applications and services without exposing the broader network.
Unlike traditional VPNs that grant broad access once a user is authenticated, ZTNA operates on the principle of “never trust, always verify.”

ZTNA ensures:

• Every request is authenticated
• Every device is validated
• Every session is authorised
• Access is restricted to only the specific applications or data a user needs.

This results in safer, more controlled remote and hybrid access, especially for cloud-based and distributed environments.

Why ZTNA Matters for London Businesses?

London organisations spanning financial services, legal firms, healthcare providers, consulting, and technology sectors increasingly depend on hybrid workforces, cloud applications, and third-party integrations.
Traditional VPNs are no longer sufficient due to over-permissive access and vulnerabilities to credential theft.

ZTNA helps London businesses:

• Prevent unauthorised lateral movement inside networks.
• Protect remote and hybrid staff accessing cloud systems.
• Reduce reliance on complex, insecure VPN infrastructures.
• Meet regulatory standards such as GDPR, FCA, NHS DSPT, and ISO 27001.
• Strengthen their Zero Trust architecture and secure digital transformation.

For Managed IT and Cyber Security providers like Support Tree, ZTNA is a cornerstone of modern access control and cloud security strategies.

Key Objectives of ZTNA

• Least Privilege Access: Only provide access to the specific apps or services required.
• Continuous Verification: Validate identity, device health, and risk level on every request.
• Secure Remote Access: Protect corporate applications from offsite users.
• Micro-Segmentation: Prevent attackers from moving laterally within environments.
• Reduced Attack Surface: Hide applications and internal assets from the internet.
• Simplified Access Management: Centralise policies across cloud and hybrid environments.

How ZTNA Works?

ZTNA typically involves four core steps:

1. User Authentication: Users authenticate through an identity provider (e.g., Microsoft Entra ID, Okta) using MFA or passwordless authentication.
2. Device Validation: ZTNA checks device posture such as OS version, encryption status, compliance, and security controls.
3. Policy Enforcement: Access is granted on a per-application basis, based on role, device health, location, and risk score.
4. Continuous Monitoring: Each session is monitored in real time for suspicious activity; access is revoked automatically if risk changes.

ZTNA solutions often integrate with:

• Microsoft Entra ID Conditional Access
• Microsoft Defender for Cloud Apps
• Firewall-as-a-Service (FWaaS)
• Secure Access Service Edge (SASE) platforms
• Identity Governance and Access Management (IAM) tools.

Best Practices for Managed ZTNA Deployment

• Use Identity-Centric Access: Rely on Entra ID or other modern IAM platforms.
• Enable Strong MFA or Passwordless: Prevent credential-based attacks.
• Combine With Endpoint Compliance: Only allow access from secure, monitored devices.
• Apply Conditional Access Policies: Control access by location, risk level, and device status.
• Implement Micro-Segmentation: Restrict internal attack paths.
• Monitor Sessions Continuously: Feed ZTNA logs into SIEM/XDR systems.
• Automate Access Reviews: Regularly verify user permissions across applications.

Support Tree deploys and manages ZTNA solutions as part of a broader Zero Trust strategy, ensuring London organisations remain secure without sacrificing productivity or usability.

Risks of Not Using ZTNA

• Lateral Movement: Attackers who compromise a VPN gain access to large parts of the network.
• Credential Theft Attacks: Weak VPN authentication leads to account takeover.
• Shadow IT Exposure: Users access unsanctioned cloud apps without security policies.
• Compliance Failures: Lack of granular access control breaches GDPR and FCA requirements.
• Insecure Remote Work: Home networks and personal devices introduce significant risk.
• High Operational Overhead: Legacy VPNs require constant maintenance, patching, and monitoring.

ZTNA directly eliminates many of these risks through identity-based control and continuous verification.

London Considerations

• Financial Services: FCA-regulated firms use ZTNA to restrict access to trading systems and confidential client data.
• Legal Practices: ZTNA enforces secure access to case management platforms and sensitive documents.
• Healthcare Providers: Securely protect clinical systems and patient portals under NHS DSPT and GDPR.
• Professional Services: Control access for consultants working across multiple client environments.
• Tech Startups: Adopt ZTNA to secure cloud-native platforms used by distributed teams.

In London’s distributed, cloud-centric business landscape, ZTNA is becoming the modern standard for secure, compliant remote access.

Example in Practice

A London-based accounting firm previously relied on a legacy VPN that provided broad network access and frequently caused authentication issues.
Support Tree implements a ZTNA solution integrated with Microsoft Entra ID, applying conditional access policies to restrict access based on device compliance and user roles.
Remote staff now connect directly to specific cloud applications without ever touching the internal network.

The result:

• Stronger protection against credential theft
• Reduced attack surface
• Seamless remote access
• Full alignment with GDPR and ISO 27001 controls.

ZTNA significantly improves the firm’s security posture while simplifying user experience and IT administration.