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Protecting your network resources in Azure Security Center | Microsoft Docs
This document addresses recommendations in Azure Security Center that help you protect your Azure network resources and stay in compliance with security policies.
security-center
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memildin
rkarlin
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security-center
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04/05/2019
memildin

Protect your network resources in Azure Security Center

Azure Security Center continuously analyzes the security state of your Azure resources for network security best practices. When Security Center identifies potential security vulnerabilities, it creates recommendations that guide you through the process of configuring the needed controls to harden and protect your resources.

This article addresses recommendations that apply to your Azure resources from a network security perspective. Networking recommendations center around next generation firewalls, Network Security Groups, JIT VM access overly permissive inbound traffic rules, and more. For a list of networking recommendations and remediation actions, see Managing security recommendations in Azure Security Center.

[!NOTE] The Networking page lets you deep dive into your Azure resource health from a network perspective. The Network map and Adaptive Network Controls are available for the Azure Security Center standard tier only. If you use the free tier, you can click the button to View legacy networking and receive networking resource recommendations.

The Networking page provides an overview of the sections you can deep dive into, to get more information about the health of your network resources:

  • Network map (Azure Security Center Standard tier only)
  • Adaptive Network Hardening
  • Networking security recommendations.
  • Legacy Networking blade (the previous networking blade)

Networking pane

Network map

The interactive network map provides a graphical view with security overlays giving you recommendations and insights for hardening your network resources. Using the map you can see the network topology of your Azure workloads, connections between your virtual machines and subnets, and the capability to drill down from the map into specific resources and the recommendations for those resources.

To open the Network map:

  1. In Security Center, under Resource Security Hygiene, select Networking.
  2. Under Network map click See topology.

The default view of the topology map displays:

  • Subscriptions you selected in Azure. The map supports multiple subscriptions.
  • VMs, subnets, and VNets of the Resource Manager resource type (Classic Azure resources are not supported)
  • Peered VNets
  • Only resources that have network recommendations with a high or medium severity
  • Internet facing resources
  • The map is optimized for the subscriptions you selected in Azure. If you modify your selection, the map is recalculated and re-optimized based on your new settings.

Networking topology map

Understanding the Network map

The Network map can show you your Azure resources in a Topology view and a Traffic view.

The topology view

In the Topology view of the networking map, you can view the following insights about your networking resources:

  • In the inner circle, you can see all the Vnets within your selected subscriptions, the next circle is all the subnets, the outer circle is all the virtual machines.
  • The lines connecting the resources in the map let you know which resources are associated with each other, and how your Azure network is structured.
  • Use the severity indicators to quickly get an overview of which resources have open recommendations from Security Center.
  • You can click any of the resources to drill down into them and view the details of that resource and its recommendations directly, and in the context of the Network map.
  • If there are too many resources being displayed on the map, Azure Security Center uses its proprietary algorithm to smart cluster your resources, highlighting the resources that are in the most critical state, and have the most high severity recommendations.

Because the map is interactive and dynamic, every node is clickable, and the view can change based on the filters:

  1. You can modify what you see on the network map by using the filters at the top. You can focus the map based on:

    • Security health: You can filter the map based on Severity (High, Medium, Low) of your Azure resources.
    • Recommendations: You can select which resources are displayed based on which recommendations are active on those resources. For example, you can view only resources for which Security Center recommends you enable Network Security Groups.
    • Network zones: By default, the map displays only Internet facing resources, you can select internal VMs as well.
  2. You can click Reset in top left corner at any time to return the map to its default state.

To drill down into a resource:

  1. When you select a specific resource on the map, the right pane opens and gives you general information about the resource, connected security solutions if there are any, and the recommendations relevant to the resource. It's the same type of behavior for each type of resource you select.
  2. When you hover over a node in the map, you can view general information about the resource, including subscription, resource type, and resource group.
  3. Use the link to zoom into the tool tip and refocus the map on that specific node.
  4. To refocus the map away from a specific node, zoom out.

The Traffic view

The Traffic view provides you with a map of all the possible traffic between your resources. This provides you with a visual map of all the rules you configured that define which resources can communicate with whom. This enables you to see the existing configuration of the network security groups as well as quickly identify possible risky configurations within your workloads.

Uncover unwanted connections

The strength of this view is in its ability to show you these allowed connections together with the vulnerabilities that exist, so you can use this cross-section of data to perform the necessary hardening on your resources.

For example, you might detect two machines that you weren’t aware could communicate, enabling you to better isolate the workloads and subnets.

Investigate resources

To drill down into a resource:

  1. When you select a specific resource on the map, the right pane opens and gives you general information about the resource, connected security solutions if there are any, and the recommendations relevant to the resource. It's the same type of behavior for each type of resource you select.
  2. Click Traffic to see the list of possible outbound and inbound traffic on the resource - this is a comprehensive list of who can communicate with the resource and who it can communicate with, and through which protocols and ports. For example, when you select a VM, all the VMs it can communicate with are shown, and when you select a subnet, all the subnets which it can communicate with are shown.

This data is based on analysis of the Network Security Groups as well as advanced machine learning algorithms that analyze multiple rules to understand their crossovers and interactions.

Networking traffic map

Legacy networking

If you don't have Security Center Standard tier, this section explains how to view free Networking recommendations.

To access this information, in the Networking blade, click View legacy networking.

Legacy Networking

Internet facing endpoints section

In the Internet facing endpoints section, you can see the virtual machines that are currently configured with an Internet facing endpoint and its status.

This table has the endpoint name, the Internet facing IP address, and the current severity status of the network security group and the NGFW recommendations. The table is sorted by severity.

Networking topology section

The Networking topology section has a hierarchical view of the resources.

This table is sorted (virtual machines and subnets) by severity.

In this topology view, the first level displays Vnets. The second displays subnets, and the third level displays the virtual machines that belong to those subnets. The right column shows the current status of the network security group recommendations for those resources.

The third level displays virtual machines, which is similar to what is described previously. You can click any resource to learn more or apply the required security control or configuration.

Network recommendations

|Recommendation name|Description|Severity|Secure score|Resource type| |----|----|----|----|----|----| |Network security groups on the subnet level should be enabled|Enable network security groups to control network access of resources deployed in your subnets.|High/ Medium|30|Subnet| |Virtual machines should be associated with a network security group|Enable Network Security Groups to control network access of your virtual machines.|High/ Medium|30|Virtual machine| |Access should be restricted for permissive network security groups with Internet-facing VMs|Harden the network security groups of your Internet-facing VMs by restricting the access of your existing allow rules.|High|20|Virtual machine| |The rules for web applications on IaaS NSGs should be hardened|Harden the network security group (NSG) of your virtual machines that are running web applications, with NSG rules that are overly permissive with regards to web application ports.|High|20|Virtual machine| |Access to App Services should be restricted|Restrict access to your App Services by changing the networking configuration, to deny inbound traffic from ranges that are too broad.|High|10|App service| |Management ports should be closed on your virtual machines|Harden the network security group of your virtual machines to restrict access to management ports.|High|10|Virtual machine| DDoS Protection Standard should be enabled|Protect virtual networks containing applications with public IPs by enabling DDoS protection service standard. DDoS protection enables mitigation of network volumetric and protocol attacks.|High|10|Virtual network| |IP forwarding on your virtual machine should be disabled|Disable IP forwarding. When IP forwarding is enabled on a virtual machine's NIC, the machine can receive traffic addressed to other destinations. IP forwarding is rarely required (for example, when using the VM as a network virtual appliance), and therefore, this should be reviewed by the network security team.|Medium|10|Virtual machine| |Web Application should only be accessible over HTTPS|Enable "HTTPS only" access for web applications. Use of HTTPS ensures server/service authentication and protects data in transit from network layer eavesdropping attacks.|Medium|20|Web application| |Just-in-time network access control should be applied on virtual machines|Apply just-in-time (JIT ) virtual machine (VM) access control to permanently lock down access to selected ports, and enable authorized users to open them, via JIT, for a limited amount of time only.|High|20|Virtual machine| |Function Apps should only be accessible over HTTPS|Enable "HTTPS only" access for function apps. Use of HTTPS ensures server/service authentication and protects data in transit from network layer eavesdropping attacks.|Medium|20|Function app| |Secure transfer to storage accounts should be enabled|Enable secure transfer to storage accounts. Secure transfer is an option that forces your storage account to accept requests only from secure connections (HTTPS). Use of HTTPS ensures authentication between the server and the service and protects data in transit from network layer attacks, such as man-in-the-middle, eavesdropping, and session-hijacking.|High|20|Storage account|

See also

To learn more about recommendations that apply to other Azure resource types, see the following:

To learn more about Security Center, see the following:

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