AWS Zero Trust Networking - Perimeterless Security with Verified Access and PrivateLink
Learn how AWS Verified Access, PrivateLink, and VPC Lattice implement zero trust networking, with a comparison of design differences from Azure Private Link.
Zero Trust Principles and AWS's Implementation Approach
Zero trust is a security model based on "never trust, always verify." While traditional perimeter-based security trusted the internal network and defended the boundary with the outside, zero trust verifies all access regardless of network location. AWS takes the approach of implementing zero trust through a combination of multiple services rather than a single service. Verified Access controls application access based on identity and device posture, PrivateLink connects inter-service communication privately without traversing the internet, and VPC Lattice provides unified management of microservice-to-microservice communication. Combining these with IAM policies enables applying zero trust principles at the network layer, application layer, and data layer respectively. The decisive difference from traditional network security is achieving secure application access without using VPNs.
Verified Access - VPN-Free Application Access
AWS Verified Access is a service that provides secure access to corporate applications without VPN. Traditionally, remote workers needed VPN connections to access internal applications, but VPNs grant access to the entire network, violating zero trust principles. Verified Access defines access policies per application, comprehensively evaluating user identity, device security posture, and access origin information to allow or deny access. It integrates with trust providers including AWS IAM Identity Center, Okta, CrowdStrike, and Jamf, enabling multi-factor decisions combining identity verification and device posture assessment. For example, you can set a policy like "allow access to the accounting system only from devices authenticated via Okta where the CrowdStrike agent is running normally." Access logs are output to CloudWatch Logs, providing complete tracking of who accessed which application and when.
Private Connectivity Between Services with PrivateLink
AWS PrivateLink is a mechanism for privately connecting resources within a VPC to AWS services or services in other VPCs without traversing the internet. When using PrivateLink, traffic travels within AWS's backbone network and is never exposed to the public internet. This directly aligns with the zero trust principle of "minimizing the attack surface." The technical mechanism of PrivateLink creates an endpoint network interface (ENI) within the VPC, and services are accessed through that ENI. DNS resolution automatically routes requests to a service's public endpoint through the private endpoint instead. If a SaaS provider offers a PrivateLink-enabled service, customers can access the SaaS from their VPC without traversing the internet. Many SaaS providers including Datadog, Snowflake, and MongoDB Atlas support PrivateLink, and the breadth of this ecosystem is also an AWS strength. Security group access controls can also be applied, maintaining fine-grained control at the network layer.
VPC Lattice - Unified Management of Microservice Communication
VPC Lattice is a relatively new service that became GA in 2023, providing unified management of microservice-to-microservice communication as an application networking service. Previously, controlling communication between microservices required combining ALB, NLB, API Gateway, App Mesh, and others, but VPC Lattice integrates these capabilities, providing service-to-service connectivity, traffic management, and access control in a single service. VPC Lattice's distinguishing feature is simplifying inter-service communication across VPC boundaries. Services in different VPCs and different accounts can be connected without configuring VPC peering or Transit Gateway. Auth policies control which services can access which other services using notation similar to IAM policies. Weighted routing for canary deployments and automatic failover through health checks are also built in, providing service mesh functionality in a managed form. The ability to uniformly manage services running on EC2, ECS, EKS, or Lambda is the key differentiator from existing load balancers.
Design Differences from Azure Private Link
Azure also offers Private Link, and the basic concept is shared with AWS PrivateLink. It creates private endpoints within a VNet to privately connect to Azure services or services in other VNets. However, there are several design differences. Azure Private Link assumes integration with Private DNS Zones, and DNS configuration can be more complex than AWS in some cases. AWS PrivateLink handles DNS resolution simply through integration with Route 53 Resolver. From the perspective of comprehensive zero trust implementation, Azure's Entra ID Conditional Access policies are powerful. Dynamic access control combining device compliance status, user risk level, and access origin location is particularly effective in environments integrated with Microsoft 365. AWS Verified Access became GA in 2023 as a newer service, and while it doesn't match Azure's Conditional Access in the number of trust provider integrations, its strength lies in simply implementing zero trust access for AWS-native applications. To learn more about zero trust design patterns, related books (Amazon) are also helpful.
Summary
AWS zero trust networking is achieved by combining Verified Access for per-application access control, PrivateLink for private inter-service connectivity, and VPC Lattice for unified microservice communication management. A VPN-independent access model, inter-service communication that doesn't traverse the internet, and unified communication management across VPC boundaries represent a fundamental shift from traditional perimeter-based security. Azure has strengths in identity-based zero trust through Entra ID Conditional Access, making it a strong option in environments with deep Microsoft ecosystem integration. AWS's greatest advantage is the flexibility to build consistent zero trust from the infrastructure layer to the application layer through the combination of IAM policies and network services.