Analyze your Virtual Machine security with Security Group View using Azure CLI

Article
12/09/2021

Note

The Security Group View API is no longer being maintained and will be deprecated soon. Please use the Effective Security Rules feature which provides the same functionality.

Security group view returns configured and effective network security rules that are applied to a virtual machine. This capability is useful to audit and diagnose Network Security Groups and rules that are configured on a VM to ensure traffic is being correctly allowed or denied. In this article, we show you how to retrieve the configured and effective security rules to a virtual machine using Azure CLI

To perform the steps in this article, you need to install the Azure CLI for Windows, Linux, or macOS.

Before you begin

This scenario assumes you have already followed the steps in Create a Network Watcher to create a Network Watcher.

Scenario

The scenario covered in this article retrieves the configured and effective security rules for a given virtual machine.

Get a VM

A virtual machine is required to run the vm list cmdlet. The following command lists the virtual machines in a resource group:

az vm list -resource-group resourceGroupName

Once you know the virtual machine, you can use the vm show cmdlet to get its resource ID:

az vm show -resource-group resourceGroupName -name virtualMachineName

Retrieve security group view

The next step is to retrieve the security group view result.

az network watcher show-security-group-view --resource-group resourceGroupName --vm vmName

Viewing the results

The following example is a shortened response of the results returned. The results show all the effective and applied security rules on the virtual machine broken down in groups of NetworkInterfaceSecurityRules, DefaultSecurityRules, and EffectiveSecurityRules.

{
  "networkInterfaces": [
    {
      "id": "/subscriptions/00000000-0000-0000-0000-0000000000000/resourceGroups/{resourceGroupName}/providers/Microsoft.Network/networkInterfaces/{nicName}",
      "resourceGroup": "{resourceGroupName}",
      "securityRuleAssociations": {
        "defaultSecurityRules": [
          {
            "access": "Allow",
            "description": "Allow inbound traffic from all VMs in VNET",
            "destinationAddressPrefix": "VirtualNetwork",
            "destinationPortRange": "*",
            "direction": "Inbound",
            "etag": null,
            "id": "/subscriptions/00000000-0000-0000-0000-0000000000000/resourceGroups//providers/Microsoft.Network/networkSecurityGroups/{nsgName}/defaultSecurityRules/AllowVnetInBound",
            "name": "AllowVnetInBound",
            "priority": 65000,
            "protocol": "*",
            "provisioningState": "Succeeded",
            "resourceGroup": "",
            "sourceAddressPrefix": "VirtualNetwork",
            "sourcePortRange": "*"
          }...
        ],
        "effectiveSecurityRules": [
          {
            "access": "Deny",
            "destinationAddressPrefix": "*",
            "destinationPortRange": "0-65535",
            "direction": "Outbound",
            "expandedDestinationAddressPrefix": null,
            "expandedSourceAddressPrefix": null,
            "name": "DefaultOutboundDenyAll",
            "priority": 65500,
            "protocol": "All",
            "sourceAddressPrefix": "*",
            "sourcePortRange": "0-65535"
          },
          {
            "access": "Allow",
            "destinationAddressPrefix": "VirtualNetwork",
            "destinationPortRange": "0-65535",
            "direction": "Outbound",
            "expandedDestinationAddressPrefix": [
              "10.1.0.0/24",
              "168.63.129.16/32"
            ],
            "expandedSourceAddressPrefix": [
              "10.1.0.0/24",
              "168.63.129.16/32"
            ],
            "name": "DefaultRule_AllowVnetOutBound",
            "priority": 65000,
            "protocol": "All",
            "sourceAddressPrefix": "VirtualNetwork",
            "sourcePortRange": "0-65535"
          },...
        ],
        "networkInterfaceAssociation": {
          "id": "/subscriptions/00000000-0000-0000-0000-0000000000000/resourceGroups/{resourceGroupName}/providers/Microsoft.Network/networkInterfaces/{nicName}",
          "resourceGroup": "{resourceGroupName}",
          "securityRules": [
            {
              "access": "Allow",
              "description": null,
              "destinationAddressPrefix": "*",
              "destinationPortRange": "3389",
              "direction": "Inbound",
              "etag": "W/\"efb606c1-2d54-475a-ab20-da3f80393577\"",
              "id": "/subscriptions/00000000-0000-0000-0000-0000000000000/resourceGroups/{resourceGroupName}/providers/Microsoft.Network/networkSecurityGroups/{nsgName}/securityRules/default-allow-rdp",
              "name": "default-allow-rdp",
              "priority": 1000,
              "protocol": "TCP",
              "provisioningState": "Succeeded",
              "resourceGroup": "{resourceGroupName}",
              "sourceAddressPrefix": "*",
              "sourcePortRange": "*"
            }
          ]
        },
        "subnetAssociation": null
      }
    }
  ]
}

Next steps

Visit Auditing Network Security Groups (NSG) with Network Watcher to learn how to automate validation of Network Security Groups.

Learn more about the security rules that are applied to your network resources by visiting Security group view overview

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