Private Networking in Azure: The Key to Data Exfiltration Prevention
Tags: cloud, azure, security
Published: 2023-03-06 23:59:57

There is an increasing threat of data exfiltration as businesses migrate their operations to the cloud. I discussed the dangers of data exfiltration in my previous article and how organisations can use the capabilities of private networks to prevent data exfiltration. The issue with the cloud is that there are so many providers out there that it can be overwhelming when choosing one that offers the right level of security. This follow-up article will provide a deeper understanding of how Microsoft Azure's private networking capabilities can be used to prevent data exfiltration. This article aims to help you better understand how Azure's networking services can be used to protect your organisation's data in the cloud.

## Private networking in Azure

Azure offers a range of networking features that help secure your data and keep it from being accessed by unauthorised individuals. There is no doubt that private networking, in particular, is a powerful tool for preventing data exfiltration since it enables you to limit network access only to trusted sources to avoid data misuse. We will explore Azure's private networking capabilities in this section and explain how they can help protect your data and keep it safe.

### Virtual networks

Azure's virtual network (VNet) is a building block for network isolation. A VNet is a logically isolated network that can span multiple Azure regions, allowing you to segment your resources and control traffic flow between them. With a VNet, you can create a secure network environment for your cloud resources and connect your virtual machines and services in a private, isolated network.

Azure provides several features to help you configure your VNet, such as subnet, network security groups (NSGs), and Azure Firewall. Subnet allows you to divide your VNet into smaller subnets for better organisation and security. NSGs provide a way to filter network traffic based on source and destination IP addresses, ports, and protocols. Azure Firewall is a fully-managed network security service that offers high availability, scalability, and integration with Azure Sentinel for threat detection and response.

### Private Link

Private Link is a feature in Azure that allows you to access services privately over an Azure Virtual Network. It has two major components: the Private Link Service and the Private Endpoint.

**Private Link Service (PLS)** is a service Azure provides that allows customers to create their endpoint for their Azure. It lets you expose a service through a private IP address in your virtual network. It's a way to connect your virtual network to a specific service endpoint through a private IP address.

From a provider perspective, you can create a Private Link Service for your Azure service, allowing your customers to connect to your service over a private endpoint. This private endpoint is assigned to the customer's virtual network, which enables them to access the service privately and securely.

**Private Endpoint (PE)** is the endpoint object that represents the connection between your virtual network and the Private Link Service. It acts as a network interface for PLS within the customer's virtual network. With a private endpoint, customers can access PLS using a personal IP address in their cloud environment, eliminating the need for a public IP address.

From a consumer perspective, you can create a Private Endpoint for your virtual network, allowing you to connect privately to a service that supports Private Links. The Private Endpoint is an interface in your virtual network that maps to the private IP address of the service you want to connect to. This way, traffic between your virtual network and the service stays within the Azure backbone network and never traverses the public internet.

When you create a private endpoint in Azure, it is associated with a specific instance of the service, and it maps to the private IP address of that service instance. This means the private endpoint is tied to a specific service instance and can only be used to access that instance.

For example, if you create a private endpoint for an Azure Storage account, the private endpoint is tied to a specific Storage account instance and can only be used to access that instance. You must create a separate private endpoint to access another Storage account instance.

This is because private endpoints are created at the service level, and each service instance has its private IP address. Therefore, if you want to access a different instance of the same service, you need to create a separate private endpoint that maps to the private IP address of that instance.

### Service Endpoints (SE)

A service endpoint is a property of a VNet subnet that enables you to extend your VNet private address space to Azure service's public IP address over a secure, optimised and low-latency connection. This is accomplished by creating a direct link between the VNet and the Azure service without requiring the traffic to traverse the public internet. Service endpoints help to secure your network traffic by limiting access to Azure services only from your VNet.

Service endpoints create a virtual network service endpoint (VNet service endpoint) within your VNet that maps to the Azure service's private IP address. When you create a service endpoint, the Azure service's firewall rules are automatically updated to allow traffic from your VNet's private IP addresses. This means traffic from other public IP addresses, including the internet, is blocked by default.

Service endpoints are available for Azure services, including Azure Storage, Azure SQL Database, and Azure Cosmos DB. You can also configure service endpoints to allow traffic from specific subnets and control which resources can access the service endpoint.

## Private Endpoints vs Service Endpoints

While both Private Endpoint and Service Endpoint provide secure connectivity to Azure services, they have some key differences. The Private Endpoint provides a private IP address and connectivity over a virtual network, while Service Endpoint provides secure and optimised connectivity over the Microsoft backbone network. Private Endpoint is ideal for scenarios where you must access an Azure service securely and privately over a virtual network. At the same time, Service Endpoint is ideal for scenarios where you need to access an Azure service securely and optimally over the Microsoft backbone network.

Another key difference is that Private Endpoint requires creating a Private Link service, while Service Endpoint does not. Private Link enables you to access Azure services over a private endpoint within your virtual network. At the same time, Service Endpoint provides a direct connection to the Azure service over the Microsoft backbone network.

A Private Endpoint is considered more secure than Service Endpoint since it provides a private IP address and connectivity over a virtual network. This ensures that the traffic between the virtual network and the Azure service remains within the private network and reduces the risk of data exfiltration. However, Service Endpoint is still a secure option, as it provides optimised routing over the Microsoft backbone network and reduces the risk of traffic interception.

## Conclusion

Preventing data exfiltration is crucial for safeguarding sensitive information in the cloud, and private networking is a vital tool for achieving this. Azure's secured networking capabilities, including virtual networks, remote endpoints, and service endpoints, provide robust and flexible options for implementing private networking in your cloud environment. By following best practices such as designing secure virtual networks, securing remote endpoints, and configuring service endpoints, you can create a strong foundation for preventing data exfiltration in Azure.

Whether you're just getting started with private networking or looking to optimise your setup, using Azure's secured virtual networking features can help you achieve increased security and peace of mind in the cloud. By prioritising data protection and implementing best practices for private networking, you can stay ahead of potential threats and keep your sensitive data safe.